% Appendix to the Errors of TeX paper (updated) % Section numbers now adjusted to TeX 3.0 equivalents % NB: tab marks are significant in this file, they signal continuation lines %\magnification=\magstephalf %\pageno=35 \input logmac * 10 Mar 1978 L1. Rename a few external variables to make their first six letters unique. D2. Initialize \\{escape_char} to $-1$, not 0 [it will be set to the first character input]. @240 L3. Fix bug: The test `$\\{id}<\O{200}$' was supposed to distinguish one-letter identifiers from longer (packed) ones, but negative values of \\{id} also pass this test. @356 B4. Fix bug: I wrote `{\bf while} $\alpha\land(\beta\lor\gamma)$' when I meant `{\bf while} $(\alpha\land\beta)\lor\gamma$'. @259 R5. Initialize the input routines in |INITEX| [at this time a short, separate program not under user control], in case errors occur. @1337 E6. Don't initialize \\{mem} in |INITEX|, it wastes time. @164 B7. Change `\\{new_line}' [which denotes a lexical scanning state] to `\\{next_line}' [which denotes \\{carriage_return} and \\{line_feed}] in print commands. F8. Include additional test `$\\{mem}[p] \ne 0\; \land$' in \\{check_mem}. @168 M9. Fix inconsistency between the \\{eq_level} conventions of \\{macro_def} and \\{eq_define}. @277 # About six hours of debugging time today. # |INITEX| appears to work, and the test routine got through \\{start_input}, \\{chcode} [the \TeX78 command for assigning a \\{cat_code}], \\{get_next}, and \\{back_input} the first time. * 11 Mar 1978 I10. Insert space before `|(|' on terminal when opening a new file. @537 F11. Put `$p\gets \\{link}(p)$' into the loop of \\{show_token_list}, so that it doesn't loop forever. @292 L12. Shift the last item found by \\{scan_toks} into the \\{info} field. [With |SAIL| all packing of fields was done by arithmetic operations, not by the compiler.] @474 B13\>12. Fix the previous bugfix: I shifted by the wrong amount. @474 I14. Add a feature that prints a warning when the end of a file page occurs within a macro definition or call. [System dependent.] @336 # Unintended bugs in my test routine [a format intended eventually to typeset {\sl The Art of Computer Programming\/}] helped check out the error recovery mechanisms. For example, I had `|\lft{#}|' instead of `|\lft{##}|' inside a macro, and three cases of improper |{|~and~|}| nesting. F15. Add the forgotten case `\\{set_font}:' to \\{eq_destroy}. @275 C16. Change |\require| to |\input|. @376 F17. Add code for the case $\\{cur_cmd}=0$ [later known as the case `$\,t\ge\\{cs_token_flag}$'] when scanning a tokenlist. @357 # That's the first ``big'' error I've spotted so far. I18. Introduce a `|d|' option in the error routine, to facilitate debugging. @84 L19. Assign a floating-point constant \\{ignore_depth} to \\{prev_depth}, instead of assigning the integer constant \\{flag} [since \\{prev_depth} is type \\{real} in \TeX78]. @215 I20. Improve the readability and spacing of \\{show_node_list} output. @182,187 F21. Set the variable $v$ before using the {\bf case} construction in \\{show_node_list}, because there's one case where $v$ didn't receive a value [as part of the field unpacking]. @182 # About seven hours today. * 12 Mar 1978 # One hour to enter yesterday's corrections and recompile. # At this point \TeX\ correctly located further unintended syntax errors in |acphdr| [the test file]. I22. Insert \\{debug_help} into \\{succumb}, giving a chance to look at memory before the system dies. @93 D23. Use \\{eq_destroy} wherever necessary in \\{unsave}. @283 L24. Change `$t \gets (t-1)$ mod 8' to `$t \gets (t-1)$ land~7' in \\{id_name}, since |SAIL| has $-1$~mod~$8 = -1$. [At this time, \\{id_name} is a routine that unpacks control sequence names, according to a scheme that will become obsolete after change \#422.] S25. Remove the space that appears at end of paragraph. (I hadn't anticipated that.) @816 L26. Throw away unwanted \\{line_feed} after getting a \\{carriage_return} in response to \\{in_chr_w} [a system routine for input from the terminal]. @83 B27. Delete spurious call to \\{flush_list} in \\{end_token_list}. @324 # Why did I make such a silly mistake? F28. Fix bug in \\{get_x_token}: I forgot to say `\\{macro_call}' (which is the main point of that routine)! @380 # While tracking that bug down, I found out incidentally that kerning is okay. # Also \TeX\ correctly caught an error |0p| for |0pt|. L29. Fix bug in \\{scan_spec} ({\bf while} instead of {\bf repeat}). @404 M30. Make the table entries for |\hfill| and |\hskip| consistent with the program conventions. @1058 L31. Disable unforeseen coercion: When \\{scan_spec} put \\{hsize} on \\{save_stack}, the value changed from \\{real} to \\{integer}. @645 I32. Use `|*|' instead of `|-1.0|' for running dimensions of rules in \\{show_node_list}. @176 D33. Clear \\{mem}[\\{head}] to null in \\{push_nest} [in \TeX82, this will be done by \\{get_avail}]. @216 # A vrule link got clobbered because I forgot to do this. I34. Translate ASCII control codes to special form when displaying them. @48,68 # Ligatures work, but \\{show_node_list} showed them funny. F35. Remember to clear parameters off \\{save_stack} in \\{package} routine. @1086 # About eight hours today. * 13 Mar 1978 D36. Introduce a new variable \\{hang_first} [later the sign of \\{hang_after}]. @849 E37\>36. Simplify the new code, realizing that if $\\{hang_indent}=0$ then \\{hang_first} is irrelevant. @848 # Time sharing is very slow today, so I'm mostly reading technical reports while waiting\/ {\bf three hours} for compiler, editor, and loading routine. # I'm not counting this as debugging time! # (Came back in the evening.) P38. Spruce up the comments in the \\{line_break} routine, which appears to be almost working. @813 D39. Rethink the setting of \\{best_line}; it's 1 too high in many cases. [The final line of a paragraph was handled in a treacherous way.] @874 D40. Compute proper initialization for \\{prev_depth} when beginning an |\hbox| with a paragraph inside. [This refers to a special `paragraph box' construction, used when an hbox of specified size becomes overfull; \TeX78 doesn't have the concept of internal vertical mode.] @1083 D41. Also initialize \\{tail} in that case. @1083 M42. Also put the result of line-breaking into the correct list. T43. Fix a typo in the \\{free_node} routine (`\\{link}' not `\\{llink}'); by strange chance it had been harmless until today. @130 F44. Fix bug: \\{post_line_break} forgot to set \\{adjust_tail}. @889 D45. Update \\{act_width} properly when looking for end of word while line breaking. @866 B46. Repair the ``tricky'' part of \\{get_node}: I used the \\{info} field when I meant to say \\{llink}. @127 # Now the |\corners| macro of |acphdr| works! [See |\setcornerrules| in {\sl The \TeX book}, page 417.] D47. Reset \\{contrib_tail} properly in \\{build_page}. @995 T48. Fix typo (|-| for |+|) in computation of \\{page_total}. @1004 S49. Change the page-breaking logic: \TeX\ reached \\{fire_up} with $\\{best_page_break}=\\{null}$ in one case, since the badness was too bad. @1005 M50. Perform the operation \\{delete_token_ref}(\\{top_mark}) only when $\\{top_mark}\ne0$. @1012 F51. Make \\{scan_toks} omit the initial |{| of an |\output| routine. @473 I52. Insert a comma to make memory usage statistics look better. @639 # About seven good hours of debugging today. # Tomorrow will be first-output day (I hope). * 14 Mar 1978 # (Came in evening after sleeping most of day, to get computer at better time.) # (Some day we will have personal computers and will live more normally.) # 8:30pm, began to enter corrections to yesterday's problems. I53. Issue an error message for non-character in filename or in font name. @771 I54. Display `|...|' for omitted stuff in \\{show_context} routine. @643 L55. Watch out for the |SAIL| syntax `$\alpha+\beta\mathbin{\rm lsh}\gamma$'; it doesn't shift $\alpha+\beta$ left (only $\beta$). @464 # That error was very hard to track down; it created a spurious link field and sent $\\{hash}[0]=\null$|\beta| to the scanner! # I could have found this bug an hour sooner if I had looked at the correct stack entries for \\{name} and \\{token_type}. D56. Show the correct page number when tracing pages before output is shipped. @638 F57. Remember to nullify a box after using it. @1079 I58. Issue an error message if\/ |\box255| isn't consumed by the output routine. @1015 # I'm having trouble with the |BAIL| debugger; it makes an illegal memory reference and dies, when single-stepping past the entry to recursive procedures \\{hlist_out} and \\{vlist_out}. So I have to reload and be careful to go thru these procedures at high speed. P59. Fix bug in comment (memory parameter description said $\ge$ not $\le$). @11 B60. Fix typo in definition of rule output (said $x,y$ not $\\{x0},\\{y0}$). [This part of the code went away when |DVI| files were introduced.] B61. Correct the embarrassing bug in shellsort, where I said `$\le\\{str}[k]$' not `$\le t$'. [The first \TeX\ had to sort all output by vertical position on page.] M62. Make \\{start_input} set up \\{job_name} in the form needed by \\{shipout}; it uses obsolete conventions. @532,537 L63. Insert |(| and |)| into the |SAIL| macro definition of \\{new_string}. [This macro was for pre-|DVI| output.] M64. Unscramble the parameters of \\{out_rule}: The declaration was $(\\{x0},\\{y0},\\{x1},\\{y1})$ while the call was $(\\{x0},\\{x1},\\{y0},\\{y1})$. # 4:30am, \TeX's first page is successfully output! # (It was `|\titlepage\setcpage1\corners\eject\end|'.) * 15 Mar 1978 # 10:30pm. Today I'm instrumenting the line-breaking routine and putting it through a bunch of tests. # (The inserted instrumentation had bugs that won't be mentioned here.) C65. Don't abort the job when \\{eq_destroy} redefines a \TeX\ control sequence. @275 # The first word of a paragraph won't be hyphenated \dots\ so be it! T66. Fix the typo in \\{line_break} that spoils the test for `letters in the same font'. @896 # The effect of that typo was to suppress all hyphenation attempts. B67\>25. Replace the space at paragraph end by fillglue, not by zero. @816 L68. Pack the hyphen character properly into its node. @582 T69. Fix a typo (`{\tentex\char'30}' for `|+|') in the computation of \\{break_width}. @838 M70. Change the |\end| maneuver; the present code doesn't end the job, since I forgot that \\{back_input} uses \\{cur_tok}. @1054 A71. Add a parameter to \\{try_break}, since the width is different at a discretionary hyphen. [This problem will be solved differently in \TeX82, when discretionaries become much more general.] @840 F72. Bypass kern nodes in pre-hyphenation. @896 F73. Supply code for the forgotten case `$<$ |"a"|' in pre-hyphenation. [This case was later generalized to a test of \\{lc_code}.] @897 B74. Change $\\{mem}[q]$ to $\\{prev_break}(q)$ in the reverse-linking loop. @878 # (Such blunders. Am I getting feeble-minded?) A75. Introduce special logic for \\{eject_penalty}; I was wrong to think that forced ejection was exactly like an infinitely negative penalty. @851 A76. Use $(1+b)^2-p^2$ when computing demerits with $p<0$. @859 # 6:30am. The line-breaking algorithm appears to be working fine and efficiently. On small measures (about 20 characters per line), it gives overfull boxes instead of spaced out ones. Surprising but satisfactory. * 16 Mar 1978 # 9pm. The plan for tonight is to test page breaking and more paragraphing. G77. Insert `|\topskip|' glue at beginning of page. @1001 I78. Add `|\pausing|' feature. @363 M79. Fix discrepancy: In \\{make_accent} I called \\{vpackage} with a pointer to the first list item, but \\{vpackage} itself assumes that the parameter is a pointer to that pointer. [The \\{vpackage} of \TeX82 will be different.] @668 # I checked for other lapses like that. Result: 14 calls OK, 12 NG. M80. Create a new temporary list head location, \\{hold_head}, since there's a case where \\{vpackage} is improperly called with parameter \\{temp_head}. [At this time \\{vpackage} uses \\{temp_head} to make a list of all insertions found.] @1014 # 11:30pm. The machine is tied up again. F81. Write code to handle charnodes in vlists; I forgot that I'd decided to allow them. [Later I prohibited them again!] @669 F82. Combine the page lists before pruning off glue in \\{fire_up}; otherwise the pruning doesn't go far enough. @1017 B83\>25. Fix typo where line-breaking starts: `\\{fill_glue}' should be `\\{new_glue}(\\{fill_glue})'. @816 I84. Add |/q| to |xspool| command (cosmetic change). [This changes a system command that causes \TeX\ output to be printed on the Xerox Graphics Printer (XGP), the progenitor of future laser printers; the |/q| option says that the queue of printing requests should be displayed on the user's terminal.] @642 E85. Don't write a form feed after the last page of output. @642 # To fix this, I reorganized \\{ship_out}, and it became simpler. T86. Correct a typo (`{\tentex\char'30}' for `|+|') in the \\{vlist_node} case within \\{hlist_out}. [The output routines were quite different at this time, because output went directly to the XGP.] @622 I87. Change the message `|completed page|' to `|Completed for page|'. @638 B88\>48. Fix yet another typo in the computation of \\{page_total}: My original code said $\\{stretch}(p)$ instead of $\\{stretch}(q)$ (terrible). @1004 P89. Document the dirty trick about \\{bot_mark}'s reference count. [That trick is, fortunately, no longer useful.] @1016 A90. Rethink the algorithm for contributing an insertion: The original code tests for a page break after incrementing the totals but before the \\{contrib_list} is updated. [\TeX78 handles insertions in a hardwired manner that will be greatly generalized in \TeX82.] F91. Fix \\{get_node} again: After the variable memory overflows, control falls through to \\{found} instead of going to the \\{overflow} call. @125 # I spent several hours tracking down that data structure bug! B92. Change \\{new_line} to \\{next_line} in yet another print command (see \#7). A93\>75. Amend the line-breaking algorithm: |\break| in paragraph doesn't work with really bad breaks. @851 # A problem to be diagnosed tomorrow: Each time I run the test program, the amount of memory in use grows by 13 cells not returned. # Seven hours tonight. * 17 Mar 1978 G94. Introduce \\{dead_cycles} to keep |\end| active until \\{ship_out} occurs. @1054 E95. Don't call \\{line_break} with an empty list. @1096 S96. Take proper account of the (infinite) fillglue when computing the width of a paragraph line preceding a display. @1146 M97. Add a new parameter to \\{hpack} so that \\{line_break} won't be called at the wrong time. [This is for the soon-to-be-obsolete feature described in \#40.] L98. Give a warning message if there's an |\hfill| in the middle of a paragraph; fillglue upsets the line breaker, because floating-point calculations don't have sufficient accuracy. @868 # I spent an hour looking for another bug in \TeX, but the following one was in \MF: The \\{xgp_height} data in fonts had been supplied wrong. # It took two hours to recompile 32 fonts with proto-\MF. R99. Make \\{show_node_list} and \\{show_token_list} more robust in the presence of software bugs. @182 D100\>97. Do not remove nodes with \\{eject_penalty}, when the new parameter to \\{hpack} is \\{true}. E101\>97. Put a fast exit into \\{hpack}; e.g., at glue nodes, test `{\bf if} \\{paragraphing} $\land$ $\langle$current width is large$\rangle$'. # 2am. I have to go to bed ``early'' tonight. * 18 Mar 1978 # 3:30pm. (Saturday) I102. Add a parameter to \\{check_mem} (to suppress display unless needed). @167 G103. Introduce a user-settable parameter |\maxdepth|, and pass it as a parameter to \\{vpackage}. @668 # I realized the need for |\maxdepth| while fixing insertions (see \#90). G104. Introduce a user-settable parameter for \\{line_break}: The constant 2.0 in my original algorithm becomes |\jpar| [later |\tolerance|], to be set like |\tracing|. @828 D105. Reclaim the \\{eject_penalty} nodes removed during line-breaking. @879 # (Those were the 13 extra nodes reported on Thursday.) # The \\{init_align} procedure worked right the first time! # Also \\{init_row}, \\{init_col}. But then\thinspace\dots S106. Rethink the command codes: \\{endv} in a token list has too high a code for the assumptions of \\{get_next}. @207 A107. Add a \\{prev_cmd} variable for processing delimited macro parameters; the original algorithm loses track of braces. [The rules will change slightly in \TeX82, and \\{rbrace_ptr} will take on a similar function.] @400 S108. Make the \\{get_next} routine intercept |&| and |\cr| tokens. @342 # I'd thought I could just put |&| and |\cr| into \\{big_switch} [i.e., in the stomach of \TeX, not the eyes]; that was a great big mistake. R109. Make more error checks on \\{endv}; e.g., it must not occur in a macro definition or call. @780 S110\>108. No, rethink alignments again; the new program still fails! @768 # For the first time I can glimpse the hairiness of alignment in general (e.g., `|\halign{\u#\v&...|' when |\u| and |\v| are defined to include |&|'s and possible alignments themselves). # I think there's a ``simple'' solution, by considering only whether an alignment is currently active [in \S342]. # 11:30pm. Went to bed. * 19 Mar 1978 # Woke up with ``better'' idea on how to handle |&| and |\cr|. # (Namely, to consider a special kind of\/ |\def| whose parameters don't interrupt on |&|'s and |\cr|'s.) # But replaced this by a much better idea (to introduce \\{align_state}). # 11pm. Began to use computer. Performed major surgery (inserting \\{align_state} and updating the associated routines and documentation). D111. Pop the alignment stacks in \\{fin_align}. @800 T112\>110. Fix a (newly inserted) typo in \\{show_context}. @314 D113\>110. Set \\{align_state} false when a live |&| or |\cr| is found. [Originally \\{align_state} was of type \\{boolean}.] @789 I114. Insert |\cr| when `|}|' occurs prematurely in an alignment. @1132 M115. Remember to record \\{glue_stretch} when packaging an unset node. @796 # I had a mistake in |acphdr| definition of\/ |\quoteformat|; also extra spaces. # My first test programs, used before today, were contrived to test macro expansion, line-breaking, and page layout. # Next I'm using a test program based on Volume 2. C116. Make carriage-return, space, and tab equivalent for macro matching. @348 F117. Omit the reference count node when displaying a mark. @176 B118. Correct a silly slip: I wrote `\\{type_displacement}' instead of `\\{value_displacement}' when packing data in a penalty node. @158 M119. Don't go to \\{build_page} after seeing |\noindent|; \TeX\ isn't ready for that. [In the original program, this was an instance of a bad {\bf goto}.] @1091 # I had undesired spaces coming thru the scanner in my macro definitions of\/ |\tenpoint| [see {\sl The \TeX book}, page 414]. # 4am. \TeX\ now knows enough to typeset page 1 of Volume 2! # Also it did its first ``math formula'' (namely `|$X$|') without crucial error. # (Except that the italic correction was missing for some reason.) D120. Remember to decrement \\{cur_level} in \\{fin_align}. [The routines will eventually become more general and use \\{unsave} here.] @800 D121. Remember to increment \\{cur_level} in error corrections by \\{handle_right_brace}. [A better procedure will be adopted later.] @1069 T122. Fix a typo: (`|{|' instead of `|}|') in error message for $\\{mmode}+ \\{math_shift}$. @1065 R123\>99. Make \\{show_noad_list} more robust and more like the new \\{show_node_list}. [The routines will be combined in \TeX82.] @690 L124. Fix a typo in \\{char_box}: should say \\{font_info_real}. [In \TeX78 a single array is used for both \\{real} and \\{integer}; in \TeX82 things will be \\{scaled}.] @554 B125. Fix typos in the definitions of \\{default_rule_thickness} and \\{big_op_spacing}; they shouldn't start at \\{mathex}(7). @701 B126. Reverse the \\{before} and \\{after} conventions in math nodes. @1196 # I had them backwards; this turned hyphenation on just before math, and off just after it! # Seven and a half hours debugging today. Got through the test program a little more. But \TeX\ blew up on `|$Y+1$|'; tomorrow I hope to find out why. * 20 Mar 1978 # 8pm. I decided to work next on a super-hairy formula. C127. Change `|\ascii|' to `|\cc|' (character code). [This name will change again later, to `|\char|'.] @265 E128. Don't bother to store a penalty node at the beginning of |$$| when the paragraph-so-far fits on a single line, since such a penalty has already been stored. [These conventions will change later, and the |\predisplaypenalty| will always be stored.] @1203 S129. Avoid reference to \\{tail} in \\{build_page}, if $\\{nest_ptr}>0$. @995 B130. Correct a silly slip in \\{math_comp} (the exact opposite of what I did in \#118). @1158 B131. Rectify my mental lapse in \\{make_fraction}; I said \\{nucleus} instead of \\{thickness}. @743 F132. Mask off the math class when scanning delimiters. @1160 C133. Allow an optional space after |\def{...}|. [This decision will be retracted later.] @473 # My test example is so complicated it causes the semantic stacks to overflow! L134. Don't test for no pages output by looking at the channel status. @642 T135. Fix typo in definition of\/ |\mathop| (\\{open_noad} not \\{op_noad}). @1156 A136. Rewrite \\{fin_mlist}, because `|\left(...\above...\right)|' doesn't parse correctly; the |\left| goes into the numerator, the |\right| into the denominator. @1184 B137. Correct the use of \\{depth_threshold} in \\{print_subsidiary_data}: Simple fields get shown while others look empty. @692 I138\>78. Return the carriage before showing the first line of a new file when pausing. @538 M139. Fix bug: The call \\{show_noad_list}(\\{mem}[|..|]) should be \\{show_noad_list}(|..|), in the \\{incompleat_noad} case of \\{show_activities}. @219 # 3am. The whole messy formula has been parsed correctly into a tree. # The easy part is done, now comes the harder part. F140. Don't shift single characters down in \\{make_op}. @749 D141. Make \\{clean_box} return a box (as its name implies), not an hlist. @720 # Font info still isn't quite right, it has the wrong value of \\{quad}. A142. Retain the italic correction when doing \\{rebox}; can make $\\{glue_set}\ne0$ a flag for this. [A better solution will be adopted later.] @715 B143. Fix the bug that makes \\{rebox} bomb out: $\\{value}(p)$ should be $\\{value}(\\{mem}[p])$. @715 # 6am; ten hours today. \TeX\ didn't do |$\pi\over2$| correctly, but was close. # I found that the \\{rebox} problem (\#142) went away when I fixed the \\{clean_box} problem (\#141); but I will leave the extra stuff about $\\{glue_set} \ne 0$ in the program anyway, just for weird cases. E144. Omit extra levels of boxing when possible in \\{clean_box}. @721 # (To do this, I need to face the \\{rebox} problem anyway.) * 21 Mar 1978 # 10pm. The computer is rather heavily loaded tonight. F145. Don't forget \\{thickness} when making a square-root sign (see \#131). [The rule thickness will later be derived from the character height.] @737 L146. Define $p$ local to the \\{make_fraction} routine. @743 # Unwittingly using the global $p$ was a disaster. I147. Don't show the amount of \\{glue_set} when it's zero. @186 D148\>142. Make \\{glue_set} nonzero in the result of \\{var_delimiter}. @706 F149. Fix bug: The \\{math_glue} function didn't return any result. @716 T150. Fix typo in \\{char_box} ($c$ not $w$); this caused a subscripted~$P$ to come out the same width as an unsubscripted~$P$. [Later changes in the rules will move this computation to \S755.] @709 P151\>144. Revise \\{clean_box} to do operations that are needed often because of the \\{rebox} change. @720 D152. Use the new \\{clean_box} to avoid a bug in |\sqrt{\raise...}|. @737 Q153. Change the definition of\/ |\not| so that it's a relation (which will butt against the following relation). [All math symbols and Greek letters are defined in |INITEX| at this time, not in a changeable format definition.] I154. Give error message `{\tt Large delimiter must be in mathex font}', instead of calling \\{confusion}, since the error can occur. [This particular error is impossible in \TeX82.] @706 F155. Change the use of $p$ in \\{var_delimiter}; it isn't always set when I say {\bf goto} \\{found}. @706 # Another font problem now surfaced: The mathex meta-font didn't compute \TeX\ info in a machine-independent way. (It took two hours to correct this.) D156. Don't forget to set $\\{type}(b)$ in all relevant cases of \\{var_delimiter}. @708 B157. Use the correct sign convention for \\{shift_amount} in \\{hpackage}. @653 F158. Always kern by \\{delta} when there's no superscript. @755 M159. Declare \\{space_table} to be $[0\,.\,.\,6,0\,.\,.\,6]$ not $[0\,.\,.\,7,0\,.\,.\,7]$; otherwise its entries are pre\-loaded into the wrong positions. [The \\{space_table} in \TeX78 is $7\times7$; it will become $8\times8$ in \TeX82, represented as a string called \\{math_spacing}.] @764 C160. Use a negative value, not zero, to represent a null delimiter. [Actually zero will come back again later.] @685 C161\>127. Change |\cc| to |\char|. @265 L162. Don't use tricky subtraction on packed data when changing $q$ to an \\{ord_noad} in \\{mlist_to_hlist}; subtraction isn't always safe. @729 B163. Fix two typos in the \\{space_table} (|*| for |0|). @764 F164. Initialize \\{cur_size} everywhere (I forgot it in two places). @703 A165. Reset \\{op_noad} before resetting \\{bin_noad}. @728 F166. Treat $\\{display_style}+\\{cramped}$ the same as \\{display_style} inside \\{make_op}. @749 B167. Shift the character correctly in the non-|\displaystyle| case of \\{make_op}. @749 # Still another font problem: The italic corrections are wrong because the corresponding array was declared \\{real} in proto-\MF\ (and italic corrections were used in nonstandard way in |mathex|). B168. Use \\{depth} instead of \\{height} in \\{var_delimiter}. [Later, both were used.] @714 Q169. Skew the accents according to the font \\{slant}. [Soon retracted.] @741 # At this point I think nearly all the math routines have been exercised. # Tomorrow they should work! # Eight hours debugging today. * 22 Mar 1978 # (Wednesday, but actually Thursday: I began at midnight because I was proofreading a paper.) # I checked out the font access tables, slowly (i.e., all the |\mathcode| and special-character name entries were catalogued). Q170\>169. Do {\bf not\/} consider slants after all in the math accent routine, since slanted math letters are put differently into fonts. @741 B171. Don't use $q$ for two different things simultaneously in \\{make_math_accent}. @738 F172. Fix bug in \\{compact_list} (I forgot to advance the loop variable). [This procedure became unnecessary in \TeX82.] M173. Avoid conflict between \\{var_delimiter} and \\{mlist_to_hlist}, which want to use \\{temp_head} simultaneously. @713 T174. Fix bad typo in \\{overbar} routine ($b$ for $p$). @705 # Finally \TeX\ got to \\{after_math} after dealing with that hairy formula\thinspace\dots T175. Fix another bad typo: $p$ for $b$ this time. @1199 L176. Insert more parentheses (twice) because of `|lsh|' precedence in |SAIL|. @1199 M177\>36. Use the new hanging-indentation conventions when formatting displayed equations. @1199 Q178. Recompute penalties so that break is allowed after \\{punct_noad}s. @761 F179. Center the large delimiters vertically. @749 Q180. Round all rule sizes (up) before drawing them. @589 Q181. Provide more space over $x$ in $\sqrt x$, and more space atop vincula. @705,737 Q182. Make large delimiters large enough to cover formula height (important for subscripts, superscripts). @762 I183. Insert |/ntn=33| on XGP prompt message so that complex math won't blow the device driver. [See \#84.] P184\>161. Update the comment about the meaning of\/ |\char|, since it can be used in math mode. @208 # Six hours today. * 23 Mar 1978 # 11pm, Maundy Thursday. C185\>104. Make |\tracing| and |\jpar| follow block structure. @283 # It took me two hours to enter yesterday's corrections, because the changes were so numerous. M186. Fix bad call on \\{begin_token_list} when marks are to be scanned. @396 # Now the formula looks like it should, modulo problems in fonts. Q187. Prevent an exponent from going below baseline + xheight/4. @758 B188. Change \\{quad} to \\{math_quad} when finishing a display (several places). @1199 A189. Don't use \\{append_to_vlist} when putting an |\eqno| box on a separate line, because the page shouldn't break at glue there. [Later, the \\{append} will be used but preceded by an infinite penalty.] @1205 S190. Increase the input \\{stack_size}; \TeX\ may need to back up a lot. @11 A191. Don't assume that $p$ always points to a glue node when a page is broken. @1017 A192. Use \\{epsilon} in \\{scan_spec} (I had used a different small constant). [This was a kludge to avoid the extra parameter later called \\{exactly} or \\{additional}.] @645 R193. Introduce a new procedure \\{scan_positive_length}, to prevent negative or zero lengths in \\{scan_rule_spec}. [This restrictive rule will be ``overruled'' later.] @463 B194. Fix ridiculous bug in the leaders routine of \\{vlist_out}: I had the initialization {\sl inside\/} the loop! @635 L195. Eliminate confusion between the two temp variables named $h$; one is \\{real} and the other is \\{integer}. @629 F196. Include forgotten case (\\{leader_node}) in \\{hlist_out}. [Type \\{leader_node} will be absorbed into \\{glue_node} in \TeX82.] @622 F197. Don't forget to compute \\{x0} in variable horizontal rules. @624 # Seven and a half hours today. # \TeX\ seems to be ready to tackle my test file based on Volume 2. S198. Calculate \\{y00} in horizontal rules as an integer number of pixels from the baseline, so that the baseline doesn't jump. @589 * 25 Mar 1978 # 2am Saturday. (Might as well drop Friday.) D199\>185. Make \\{def_code} consistent with the new |\tracing| conventions. [Many tracing options are packed into a single parameter called |\tracing|.] @1233 R200\>185. Don't allow users to change nonexistent things like |\catcode1000|. @1232 F201\>110. Reset \\{align_state} at beginning of \\{init_align}. @774 F202. Don't forget \\{scan_left_brace} after |\noalign|. @785 F203\>110. Set $\\{cur_cs}\gets 0$ in \\{get_next}, after |\cr| causes a switch to the $\langle v_j\rangle$ template. @342 # Ouch, that was a big bad bug, which took me three hours to find (since I thought \TeX's low-level scanning mechanism was working). # Note to myself: I\/ {\bf knew\/} it would be cleaner to define \\{get_next} so that it sets \\{cur_cs} to zero every time it begins [i.e., in \S341, where this change will in fact be made in \TeX82]. But I had avoided this on grounds of efficiency in the inner loop. Well, now I have earned this tiny bit of efficiency. D204. Prohibit the first word of an unavailable node from becoming negative. [The storage allocator of \TeX78 uses a negative value to signify a node that is available, just as `$\\{link}=\\{max_halfword}$' will signal availability in \TeX82.] @124 # That was another bad one, it's not my night. # At least I'm developing more subtle diagnostic techniques. M205. Remember to un-negate the top \\{save_stack} entry when \\{handle_right_brace} finishes an \\{insert_group}. [This routine was completely revised in \TeX82.] @1100 F206\>185. Initialize |\jpar| [i.e., |\tolerance|]. @240 B207. Correct the display of insertion nodes by \\{show_node_list}. @188 R208. Prevent \\{show_token_list} from generating really long strings when in a loop. @292 D209. Increase the reference count of \\{bot_mark} when \\{vpackage} finds it. [This was later the job of \\{fire_up}.] @1016 M210. Remember that the tokenlist for a mark ends with a |}|. @1101 D211. Don't let \\{vpackage} lose the top insert. (It fails when the very first item is a |\topinsert|.) @1014 A212. And when that stupid code is corrected, make it handle insertions first-in-first-out. @1018 # Seven hours today. * 26 Mar 1978 # Easter Sunday, will work till sunrise. I213. Add an `|i|' feature to the \\{error} recovery routine. @87 I214. Include a prompt. @87 C215. Ignore space after |\noalign{...}|. @1133 # Otherwise, things are going well tonight; I'm finding more bugs in my test program than in \TeX. # The `|i|' feature is proving to be very helpful. # I increased the size of \\{mem} (now $\\{lo_mem_max}=3500$, $\\{mem_max}=10000$). # In fact I just needed to increase it again (now $\\{lo_mem_max}=4500$, $\\{mem_max}=11000$). R216. Make |INITEX| output \\{mem_top} for consistency checking. @1307 A217. Calculate the size of delimiters by considering the enclosed formula's distance from the axis, not from the baseline. @762 # I'm having trouble with a |SAIL| compiler bug; I must rearrange the program, more or less at random, until it compiles correctly. I hope the bug isn't more severe than it appears. D218\>210. Don't put a new group on \\{save_stack} if a null mark is expanded. [\TeX82 will remove the `|}|' from the mark text.] @386 # I had to redo the typewriter-style font since its width tables were wrong. # And I increased low-memory size again to 5500, then 6500. # Finally the entire test program was \TeX ed. Happy Easter! Six hours today. * 27 Mar 1978 # Beginning at 2:30am. A219. Move |\vcenter| processing to the first pass of \\{mlist_to_hlist}; otherwise the height, depth, subscripts, etc., are way off. @733 C220. Omit space after closing |$$|. @1200 # Spacing is wrong in the formula $Y_1+\cdots+Y_k$; I have to rethink the use of three dots. G221. Make conditional thin space available to user as |\|{\tentex\char'34}. [Later will retract this.] @226 Q222. Introduce |\dispaskip| and |\dispbskip| [later called |\abovedisplayshortskip| and |\belowdisplayshortskip|]. @226 # Reminder: I need to test line-breaking with embedded math formulas. I223. Make sure that $\\{interaction}\ne\\{error_stop_mode}$ in the `|Whoa|' error [\\{fatal_error}]. @93 B224. Fix a big mistake in the \\{style_node} routine (which points to a glue spec, not to glue itself); somehow this didn't cause trouble yesterday. [In \TeX78, style nodes double as placeholders for math glue like thin spaces.] @732 C225. Make |\fntfam| obey group structure. [\TeX78's |\fntfam| operation is a combination of \TeX82's |\textfont|, |\scriptfont|, and |\scriptscriptfont|.] @1234 # At this point the test routine for Volume 2 works perfectly. # But I will change the page width in order to check harder cases. Q226\>178. Disable automatic line breaks after punctuation in math (e.g., consider $f(x,y)$). @761 S227. Represent italic corrections as boxes, not glue, so that they won't be broken. [The |\kern| command doesn't exist yet.] @1113 # Eight hours today. B228. Fix a bug that just clobbered the memory: Call \\{free_avail}, not \\{free_node}, in the \\{ins_node} case of \\{vpackage}. [This logic will change completely in \TeX82.] @1019 * 29 Mar 1978 # (Wednesday) Again beginning at 2:30am. Q229. Put still more space above and below fraction lines in displayed formulas. @746 G230\>189. Install an infinite penalty feature, which positively suppresses breaks; use it in displayed formulas whose |\eqno| doesn't fit. @1205 F231. Call \\{build_page} after finishing a display; and don't go to the |\noindent| routine because of the next remark. @1200 S232. Put |\parskip| glue just before a paragraph, not just after (since it interferes with a penalty after). @1091 # Although the test program gives correct output, it generates 46 locations of variable-size memory and 280 of one-word memory that are not freed. F233. Recycle the ulists and vlists in \\{fin_align}. @801 M234\>25. Fix bug when deleting space at end of paragraph: \\{delete_glue_ref}(\\{cur_node}) not \\{delete_glue_ref}(\\{value}(\\{cur_node})). @816 # There's also a more mysterious type of uncollected garbage, a \\{fraction_noad} corresponding to |$p\choose$|, an \\{incompleat_noad} not completed. # Couldn't find that one, so I recompiled with \#233 and \#234 corrected. # Now it gains just 10 locations of variable-size memory and 7 of the other kind. I235. Extend \\{search_mem} to search \\{eqtb} also. @255 D236\>143. Fix bug in \\{rebox} when $\\{list_ptr}(b)=0$. @715 # The seven one-word nodes were generated by this bug; \\{rebox}\kern-1pt\ put them onto a linked list starting with $\\{mem}[0]$, growing at the far end! D237. Remember to complete each \\{incompleat_noad}. @1184 # This solved the other mystery. I had never noticed that my test output was actually wrong: |$p\choose k$| came out as `$k$'. # After these corrections, the test routine worked\thinspace\dots\ I feel that \TeX\ is now pretty well debugged (except perhaps for error recovery)---it's time to celebrate! * 1 Apr 1978 I238. Don't quit after file lookup fails. @530 * 2 Apr 1978 P239. Add \\{\TeX_font_area}, so that it's easier to change the default library area associated with a device. @514 * 3 Apr 1978 L240. Insert parentheses again, to cope with the precedence of\/ |lsh| when packing data. (See \#55 and \#176.) @1114 # I had never tried $\\{hmode}+\\{discretionary}$ before! M241. Remember that \\{back_error} requires \\{cur_tok} to be set. (Problem can arise during error recovery on parameter |#|$n$ with $n$ out of range.) @476 * 4 Apr 1978 I242. Add a deletion feature to the \\{error} routine. @88 * 5 Apr 1978 Q243. Reset \\{space_factor} after |\/| [this was later rescinded] and after math in text. @1196 * 10 Apr 1978 G244\>104. Replace |\jpar| and |\tracing| by a new primitive |\chpar| for parameters. It allows a user to change those quantities as well as the penalties for hyphens, relations, binary ops, widows. @209 * 14 May 1978 # Beginning to typeset a real book (Volume 2, second edition), not just a test. Q245. Make math in text end with spacing as if it were followed by punctuation. [This rule will soon be rescinded.] @760 F246. Insert |\times| into the hash table; I left it out by mistake. [It will eventually move into |plain.tex|.] C247. Change the names of Scandinavian accents from |\o|, |\oslash|, |\Oslash| to |\a|, |\o|, |\O|. [This will also move to |plain|.] * 17 May 1978 B248. Fix a silly bug that hasn't been tweaked until today: `|\halign to size|' [obsolete in \TeX82] used \\{vsize} instead of \\{hsize}. @645 * 19 May 1978 G249. Add a |\topbaseline| feature [later called |\topskip|]. @1001 Q250\>245. Subtract the math spacing change of May 14. @760 A251. Skip past blanks in the \\{scan_math} procedure. [This blank-skipping will eventually go into \\{scan_left_brace}.] @403 I252. Introduce a \\{missing_brace} routine [later generalized] to improve error recovery in $\\{mmode}+\\{math_shift}$, when the top of \\{save_stack} isn't a \\{math_shift_group}. @1065 Q253. Adjust the math spacing between closing parentheses and Ord, Op, Open, Punct. @764 Q254. Make the underline go further under. @735 S255\>96. Compute the proper natural width when a displayed equation follows a paragraph whose fillglue has been deleted by \\{line_break}. @1146 * 20 May 1978 A256. Fix the spurious value of \\{prev_depth} inside alignments. @775 S257. Consider (and defeat) the following scenario: The u and v lists are built in \\{init_align} using \\{temp_head}; then while scanning `|\tabskip 2pt\rt{...}|' the macro |\rt| is expanded, clobbering \\{temp_head}. @779 # That bug was more subtle than usual. Q258. Add the parameter \\{num3}, so that the positioning of\/ |\atop| can be different from that for fractions. @700 Q259. Add new parameters \\{delim1} and \\{delim2}, so that |\comb| can use fixed size delimiters, not computed as with |\left|. @748 * 22 May 1978 C260\>221. Change |\|{\tentex\char'34} to |\|{\tentex\char'35} and introduce |\|{\tentex\char'34} as the negative of\/ |\|{\tentex\char'35}. [Later obsolete.] @226 L261. Fix the display of negative penalty nodes; \\{show_node_list} is confused when a negative value has been packed into the middle of a word. @194 # Memory overflow just occurred with $\\{lo_mem_max}=7500$ and $\\{mem_max}=16384$. So I have to go to 15-bit pointers. (A problem on 32-bit machines?) * 23 May 1978 Q262. Add a new parameter \\{big_op_spacing5}, for extra space above and below limits of big displayed operators. @751 F263. Initialize \\{incompleat_noad} in |$$\halign{...}$$|. @775 # That was another heretofore-untested operation. How much of the code has not yet been exercised? F264\>238. Close the file when doing lookup-failure recovery. @27 I265. Improve the error recovery for `|Extra &|'. @792 R266. The top piece must be calculated mod 128 in \\{var_delimiter}, to guarantee a valid subscript range. [Obsolete in \TeX82.] @546 B267\>252. Fix a blunder in new \\{missing_brace} code. @1065 B268\>262. Fix a blunder in new code for limits on display operators. @751 * 26 May 1978 Q269. Don't insert a new penalty after an explicit penalty in math mode. @767 # The hash table overflowed; I ought to make it much bigger. R270\>110. Avoid possible bad memory references in alignment when there is erroneous input after |\cr|. [Instead of \\{extra_info}, the value of \\{cur_align} in \TeX78 is negated, because we need only distinguish |\cr| from |&|.] @789 S271. Make the dimension parameters like |\hsize| all global, so that they can be set in the |\output| routine. @279 # This led to major simplifications, also to major surgery. # [But it was a kludgy decision, overruled in \TeX82.] D272\>94. Don't forget to set the type of the new null box in the |\end| routine. @1054 * 27 May 1978 # The data overflowed memory again, both low and high, doing Section 3.3.2. R273\>184. Mask off extra bits of\/ |\char| in math mode, to avoid bad memory references. @1151 B274. Zero out the negative |\medmuskip| in script styles. @732 * 29 May 1978 S275. Be prepared to handle an undefined control sequence during \\{get_x_token}. (Can fix this by brute force, using \\{get_token} instead of \\{get_next}.) @380 D276. Correct the superscript shift when a single character is raised. @758 R277\>184. Mask off all but 7 bits in |\char| routine, to avoid space-factor index out of range. @435 # More memory capacity overflows. E278\>22. Fix \TeX's overflow stop so that I don't have to wait for loading of the |BAIL| debug routines. [System dependent.] @93 F279. Remember to adjust the page number when a file page ends in mid-macro. [System dependent.] @306 * 5 Jun 1978 R280. Make sure that the arguments of positioning commands don't overflow their field size. @610 I281. Report the excess amount when giving an overfull box warning. @666,677 * 7 Jun 1978 Q282. Use $\ge$ instead of $>$ as termination criterion in \\{var_delimiter}. @714 R283. Disallow |\eject| in math mode. [In \TeX78, |\eject| is distinct from |\break|; in horizontal mode it includes \TeX82's `|\vadjust{\break}|'.] @1102 Q284. Don't put too much clearance above |\sqrt| in text style. @737 * 9 Jun 1978 G285\>110. Make \\{align_state} an integer variable, not \\{boolean}, so that |\eqalign| can be within another |\eqalign|. @309 C286. A |\mark| should expand its input. @1101 * 10 Jun 1978 E287. Provide for preloading of fonts. @1320 L288. Close the output file before switching to edit the input file with the `|e|' option. @84 E289. Return adjustments found by \\{hpack} to free storage if they're not used. [Later, \\{hpack} will detach them only when they're used.] @655 Q290. Strive for consistency between \\{make_under} and \\{make_over}. @735 * 18 Jun 1978 B291\>236. Fix a serious error in \\{rebox} (`$b$' instead of `$\\{list_ptr}(b)$'). @715 # Strange that such a bug would now surface for the first time! C292. Remove |\deg| from |INITEX|, since macros suffice. Q293. Add an extra hyphenation penalty for two hyphenated lines in a row. @859 * 19 Jun 1978 S294. Introduce the `\\{no_new_control_sequence}' switch. Among other things, this will prevent an undefined control sequence following \\{scan_math} from clobbering the save stack. @259 * 20 Jun 1978 L295. Change the badness test `$\\{glue}\le0.0$' to `$\\{glue}\le0.0001$'. [\TeX82 will avoid such problems by calculating badness without floating point arithmetic.] @99 R296. Force \\{badness} to be at most $10^{19}$. @108 I297. Add \\{end_template} for better error recovery in alignments. @375 E298\>287. Make |INITEX| more like the real \TeX; my simple scheme for font preloading was no good because it left thousands of `dead' words in memory. @8 E299. Economize disk space by using internal arrays in load modules that aren't being reinitialized. [System dependent.] E300. Move the declaration of \\{mem} to the semantics module, so that the object code will be more efficient. [System dependent. The code of \TeX78 was divided into separately compiled modules for syntax, semantics, output, extensions, and general organization.] * 21 Jun 1978 # Today I'm working on the user manual. C301. Disallow |\input| except in vertical mode. [I will change this in \TeX82, treating |\input| as a case of expansion.] @378 I302. Add error recovery for \\{endv} and \\{par_end} occurring in math mode. @1047 G303. Generalize |\ifT| to |\if T|. @506 * 22 Jun 1978 F304. Preload the |\bullet| [later done by |plain.tex|]. D305\>256. Get the correct \\{prev_depth} at the beginning of an alignment. @775 C306. Change |\eject| so that it ejects only once. @1000 * 14 Jul 1978 I307. Look in standard area if a file isn't found in the user's area. @537 I308. Echo all online inputs in the transcript file. @71 * 19 Jul 1978 Q309. Equalize spacing when only one of numerator/denominator is big. @745 Q310. Prevent subscript from getting too high above baseline. @757 R311. Avoid infinite loop when stack overflows: \\{push_input} should say `{\bf if} $\\{input_ptr}\ge\\{stack_size}\;\land\;\\{interaction}= \\{error_stop_mode}$'. @321 * 22 Jul 1978 C312. Make |\quad| meaningful outside math mode. (All fonts must be generated again!) @558 I313. Show the nesting level at the end of \\{show_activities}. [But I decided not to do this in \TeX82.] @218 C314. Put in |\>| [namely, |\mskip\medmuskip|; \TeX78 already has |\|{\tentex\char'35}, for conditional |\thinmuskip|, as well as the negative amounts |\<|,~|\|{\tentex\char'34}]. Change the name of vector accent from |\>| to |\b|. [Math spacing operators will become much more general in \TeX82.] @716 * 25 Jul 1978 Q315\>94. Give the correct |\hsize| and |\vsize| to the null boxes created at |\end|. @1054 A316\>94. And don't ``append'' them. [Later this was changed, so that it would work better with generalized output routines.] @1054 I317\>297. Remove the control sequence |\endv|, since error recovery is now better. @375 I318. Define another mode of tracing: It says `|OK|' and stops after |\showlists|. @1298 Q319\>244. Give better defaults to parameters. [Later done by |plain.tex|.] @209 I320. Allow more bits in the packed representation of\/ |\showboxdepth|. @238 I321. Scan past delimiters and/or dimensions when recovering from ambiguous fractions. @1183 R322. Reduce accent numbers modulo 128 or 512, depending on the mode. @1165 I323. Include a warning, `|(\end occurred on level ...)|'. @1335 * 28 Jul 1978 # (I'm writing Chapter 27 of the manual: `Recovery From Errors'.) I324. Improve the error message in \\{scan_digit}. [This procedure will change its name to \\{scan_eight_bit_int}, when the number of registers increases from 10 to~256.] @433 I325. Don't report overfull boxes if they're less than .1~point over. @666,677 I326. Give the user extra chances to define the font, if \\{read_font_info} is unsuccessful. @560 I327. Change default recovery for bad parameter number from |#1| to |##|, since |#1| won't always work and since |##| is probably intended. @479 I328. Omit the |"Negative?"| message on things like \\{scan_char_num}. @435 I329. Improve error recovery when a large delimiter isn't in family~3. [Obsolete.] I330. Give a more appropriate error message when the input is `|$\right|'. @1192 # Currently \TeX\ says `|Missing $|'! I331. Call \\{back_input} before the error message in \\{back_error}, not afterwards. @327 * 1 Aug 1978 I332. Give an appropriate warning when there's no input file and the user types `|e|'. @84 L333. Increase the system pushdownlist size so that the manual will compile. [Procedures \\{hlist_out} and \\{vlist_out} can recurse deeply.] # Yesterday I distributed 45 preliminary copies of the manual; today I took out the ``debugging hooks'' and put \TeX\ up as a system program. * 2 Aug 1978 # I'm typing Volume 2 again (currently in Section 4.2.2). Culture shock! G334. Introduce a |\ragged| parameter, to indicate a degree of raggedness. [Previously, ragged-right setting was performed when the |\tolerance|/100 was odd! Eventually a better approach, with |\rightskip| and such things, will be discovered.] @886 Q335. Omit the `widow penalty' in one-line paragraphs. @890 * 5 Aug 1978 G336. Generalize |\pageno| to |\count|\. @236 D337\>285. Update \\{align_state} when recovering from `|Missing {|' and `|Extra }|' errors. @1069,1127 I338. Show ``runaway'' tokens, making it easier to pinpoint an error. @306 * 22 Aug 1978 G339. Add |\predisplaypenalty|. @1203 I340. Clarify error messages; they should indicate when something has been inserted, etc. @1064 * 23 Aug 1978 I341\>114. Substitute `|Extra }|' for the losing `|Missing \cr|' error message. @1069 I342\>213. Go past online insertions in \\{show_context}. @311 Q343. Exact no penalty for breaking one line before a display. @1145 I344\>338. Check for runaways at end of file. @362 I345. Give error message when a macro argument begins with |}|. @395 * 24 Aug 1978 L346\>213. Remove extra line-feed in \\{show_context} after printing insertions. [System dependent.] @318 * 25 Aug 1978 Q347. Leave no glue at top of page, even after |\eject|. @997 * 27 Aug 1978 P348. Adopt Guy Steele's new version of the \TeX\ source files. [He has recently made a copy and modified it by introducing compile-time switches for MIT conventions as an alternative to SUAI. This is the first time that \TeX\ is being ported to another site; additional switches for PARC, TENEX, TOPS10, and TOPS20 will be added later, using the Steele style.] * 1 Sep 1978 Q349. Don't pass over leader nodes in the \\{try_break} background computation. [At this time, leaders have not yet been unified with glue.] @837 Q350\>82. Prune away all penalties at the top of a page. @997 * 4 Sep 1978 I351\>338. Include `|\|' in error message about a runaway argument. @306 * 8 Sep 1978 # I just remade all the fonts, with increased ligature field size. B352\>350. Insert a necessary {\bf goto} statement in the first branch of the new penalty routine within \\{build_page}. @997 * 30 Sep 1978 M353\>338. Make the token list for runaway arguments meaningful outside of \\{macro_call}. (I just had a runaway argument ending with `|\lcm|', which turned out to be the control sequence in hashtable location 0.) @371 R354. Avoid infinite loop when recovering from |$$| in restricted horizontal mode. @1138 L355. Fix two hyphenation bugs related to |-ages|, |-ers|. [A completely new algorithm for hyphenation will go into \TeX82.] Q356. Add |-est| to hyphenation routine; also disable |puz-zled| and |rat-tled|, etc. * 4 Oct 1978 G357. Add new primitive |\vtop|. @1087 Q358. Treat implicit kerns properly after discretionary hyphens have been inserted. @914 * 4 Nov 1978 Q359. Forget the half quad originally required at left and right when centering displayed equations without equation numbers. @1202 * 11 Nov 1978 R360. Don't let the postamble come out empty. [This could occur if no fonts were selected.] @642 * 15 Nov 1978 C361. Allow optional space after digit in \\{scan_int} routine. @444 * 17 Nov 1978 R362. Make the \\{check_mem} procedure slightly more robust. @167 * 20 Nov 1978 C363. Make the |\par| in a |\def| match the |\par| that comes automatically with a blank line. (Suggested by Terry Winograd.) @351 G364. Add new parameter |\mathsurround| for spacing before and after math in text. @1196 G365. Extend |\advance| to allow increase by other than unity. [At this time it applies only to the ten |\count| registers, and it is called |\advcount|.] @1238 * 25 Nov 1978 G366. Add a new primitive: |\unskip|. @1105 G367. Add new primitives |\uppercase| and |\lowercase|. @1288 * 28 Nov 1978 M368\>338. Don't let |\mark| and \\{macro_call} interfere with each other's \\{scanner_status}. @306 M369. Omit extra |}| after \\{show_node_list} shows a |\mark|, since the right brace is already there. (See \#210.) @176 G370. Add a new primitive suggested by Terry Winograd: |\xdef|. @1218 * 29 Nov 1978 S371. Delete a space following |\else{...}| also in the false case. [\TeX78 uses braces, not |\fi|, for conditionals.] D372\>320. Make |\tracing| set |\showboxbreadth| as advertised. @198 F373. Account properly for kerns in width calculations of \\{line_break}. @866 Q374\>364. Delete a \\{math_node} at the beginning of a line. @148 A375\>339. Guarantee that |\predisplaypenalty=10000| will suppress page breaking before a display. @1005 * 6 Dec 1978 L376. Change the file opening statement to allow lines up to 150 characters long. [System dependent.] * 16 Jan 1979 F377\>365. Initialize \\{negative} properly in the |\advance| routine with a |\count| as argument. @440 * 20 Jan 1979 R378. Try to keep complex, buggy preambles of alignments from crashing the program. @789 * 17 Feb 1979 I379\>376. Give more detailed information when warning about a long line being broken. [System dependent; the buffer size in \TeX78 is very limited.] L380. Declare $p$ local to \\{try_break}, for the ``rare'' case code. [My original program included the following comment: ``This case can arise only in weird circumstances due to changing line lengths, and the code may in fact never be executed.'' Later Michael Plass will discover that variable line lengths require an entirely different algorithm, using \\{last_special_line}.] @847 F381\>334. Don't omit the raggedness correction when the last line of paragraph has to shrink. [Obsolete in \TeX82.] * 22 Feb 1979 F382\>363. Don't forget to return from \\{get_x_token} after finding |\par|. @351 Q383. Add a new parameter: |\lineskiplimit|. @679 C384. Change the syntactic sugar: `|\hbox par|' replaces `|\hjust to ...{overfull}|'. [This vastly improves on the old idea (see \#40), but there still is no internal vertical mode.] C385. Introduce new names |\hbox| and |\vbox| for |\hjust| and |\vjust|. @1071 G386. Add a new condition: |\ifpos|. [It will later be generalized to |\ifnum| and |\ifdim|.] @513 G387. Add |vu| and |\varunit|. [\TeX82 will eventually allow arbitrary internal dimensions as units of measure.] @453 G388\>312. Add an |em| unit. @455 C389. Legalize |\hbox spread |\ [since \\{scan_spec} no longer uses the sign as a flag]. @645 * 10 Mar 1979 C390\>370. Make \\{scan_toks} expand |\count| during |\xdef|. [This will change later when |\the| and |\number| are introduced.] @367 * 23 Mar 1979 Q391. Put only 100000\thinspace pt stretch at the end of a paragraph instead of 10000000000\thinspace pt. [In \TeX78, ``infinite'' glue is actually finite but large; in the language of \TeX82 we would say that |\parfillskip|, which is not yet user-settable, is being changed to be like |\hfil| instead of like |\hfill|.] @816 Q392. Treat the last line of a paragraph more consistently with the other lines (e.g., when |\hfil| appears in mid-paragraph), by effectively inserting \\{inf_penalty} at the end. @816 * 31 Mar 1979 S393. Ensure that penalty nodes aren't wiped out, in weird cases where breaks occur at penalties that normally disappear. @879 * 27 Apr 1979 A394. Correct the page number count when files begin with an empty page. [System dependent.] G395. Allow the \\{math_code} table to be changeable via |\chcode|. [In \TeX82, |\chcode| will split into |\mathcode| and |\catcode|.] @1232 I396\>332. Don't accept `|e|' after an error message if not inputting from a file. @84 * 29 May 1979 F397. Don't call \\{end_file_reading} if you haven't already invoked \\{begin_file_reading}; this could happen when trying to recover from an error in \\{start_input}.@537 * 7 Jun 1979 A398\>306. Be sure to eject two pages, when |\eject| comes just at the time another break is preferable (e.g., when the page has just become too full). @1005 * 27 Jun 1979 I399\>354. Don't say `|You can't do that in math mode|' when the user says `|$$|' in restricted horizontal mode! @1138 * 30 Jun 1979 G400. Add |wd|, |dp|, |ht| dimension units. @455 I401\>307. Don't try the system area for file names whose area is explicitly indicated. @537 * 1 Jul 1979 G402. Allow letters as (ASCII) numbers [without the |`| marker introduced later]. @442 * 2 Jul 1979 F403. Fix a |\gdef| bug: If the control sequence was never defined before [this later became the \\{restore_zero} option], don't remove it at group end. @282 * 16 Jul 1979 I404\>320. Update \\{show_noad_list} to be like \\{show_node_list}. [The two routines, originally separate, will be merged in \TeX82.] @238 * 18 Jul 1979 G405. Extend capacity from 32 fonts to 64 fonts if desired. @134 Q406. Add new \\{extra_space} parameter to all text fonts (requested by Frances Yao). @558 F407. Make each \\{node_noad} print properly in \\{show_noad_list}. @183 Q408. Make |\jpar| allow any break if it is 1000000 or more. [In \TeX82, a |\tolerance| of 10000 or more allows any break.] @851 * 23 Jul 1979 E409. Introduce new primitives |\hfil|, |\vfil|, |\hfilneg|, |\vfilneg|. @1058 G410. Add |\ifmmode|. @501 G411. Add |\firstmark|. @1012,1016 C412. Allow break at leaders (horizontal mode only). @149 * 25 Jul 1979 I413\>213. Revise \\{error} so that online insertions work properly after end-of-file errors. @336 B414\>411. Change `{\bf if} $\\{first_mark}\ne0$' to `{\bf if} $\\{first_mark}\ge0$' [because $-1$ is used to indicate `not yet given a value']. @1012 * 28 Jul 1979 C415\>370. Stop |\xdef| from expanding control sequences after |\def|'s. [This decision will be rescinded later, after several more years of experience with macro expansion will suggest better ways to cure the problem.] @366 I416. Change symbolic printout for control symbols. [System dependent.] @49 L417\>308. Avoid linefeeds in the transcript file. [System dependent.] C418\>370. Expand |\topmark|, etc., in |\xdef|. @366 * 4 Aug 1979 B419\>413. Fix an error introduced recently: |\par| was suddenly omitted at end of page. [System dependent.] * 11 Aug 1979 P420. Change error messages that use |SAIL| characters not in standard ASCII. @360 * 28 Aug 1979 D421\>411. Move the command `$\\{first_mark}\gets-1$' from \\{vpackage} to \\{fire_up}. @1012 S422\>403. Correct a serious |\gdef| bug: Control sequences don't obey a last-in-first-out discipline, so \TeX\ loses things from the hash table when deleting a control sequence. @259 # To fix this, I either need to restrict \TeX\ (so that |\gdef| can be used inside a group only for control sequences already defined on the outer level) or need to change the hash table algorithm. Although all applications of \TeX\ known to me will agree to the former restriction, I've chosen the latter alternative, because it gives me a chance to improve the language: Control sequences of arbitrary length will now be recognized. D423. Make sure that \\{unsave} cannot call \\{eq_destroy} with a value from the upper part of \\{eqtb}. @282 # I noticed this long-standing bug while fixing \#422. It had very low probability of causing damage (e.g., it required a certain field of a floating-point number to have a certain value), but it would have been devastating on the day it first showed up! * 29 Aug 1979 F424. Call \\{eq_destroy} when a control sequence is |\gdef|'ed after being |\def|'ed. @283 F425\>418. Treat the first token consistently when |\topmark| and its cousins are expanded in \\{scan_toks}. @477 # Now I've checked things pretty carefully and I think \TeX\ is ``fully debugged.'' * 25 Jan 1980 I426\>338. Display runaway alignment preambles. @306 G427. Introduce active characters (one-stroke control sequences). [I don't yet go all the way: The meanings of `|x|' and `|\x|' have to be identical.] @344 * 7 Feb 1980 F428\>314. Fix a glaring omission: Op space |\>| was never implemented in math mode! @716 * 25 Feb 1980 G429. Add a new dimension `|ex|' (for units of xheight). @455 * 3 Mar 1980 C430\>427. Allow the control sequence |\:| to be redefined [it was the `select font' operator]; this allows the character |:| to be active. [Obsolete.] * 23 Mar 1980 # An extend-\TeX-for-the-eighties party: G431. Add a new |\copy| feature. @204 G432. Add a new |\unbox| feature. @1110 G433. Add a new |\open| feature [later |\openout|]. @1351 G434. Add a new |\send| feature [later |\write|]. @1352 G435. Add a new |\leqno| feature, requested by MDS. @1204 G436. Add a new |\ifdimen| feature [later |\ifdim|]. @513 C437. Make |\|\ in vertical mode begin a paragraph. @1090 G438. Add a new |\font| feature [replacing the silly previous convention that a font must be defined when it is first selected]. @1256 G439. Add new |\parval| and |\codeval| features [later |\the|\thinspace\\thinspace]. @413 C440\>427. Don't let active characters gobble the following space. @344 G441\>208. Add a new parameter to govern amount of token list dumped. [Obsolete.] @295 G442. Add a new |\linebreak| feature [later replaced by |\break|]. @831 * 25 Mar 1980 # (Still working on the above, also thought of more.) G443. Add a new |\mskip| feature. @716 G444. Add a new |\newname| feature (soon changed to |\let|). @1221 G445\>430. Allow any control sequence to be redefined. @275 I446. Send the output to the user's current file area, even when input comes from elsewhere. @532 * 27 Mar 1980 Q447. Compute the xheight for accents in math mode from family~1, not family~3. [Obsolete.] * 28 Mar 1980 Q448. Increase minimum clearance between subscript and superscript. @759 * 29 Mar 1980 Q449\>222. When a display follows a display, the second should have the `shortskip' glue. @1146 * 4 Apr 1980 A450\>445. Look at current token meanings when trying to recognize |\tabskip| in alignment preambles. @782 * 23 Apr 1980 I451. Estimate the length of printed output, for the new priority feature on our XGP device driver. [System dependent.] C452\>434. Break long |\send| lines into pieces so that the file can be read in again. [System dependent.] * 19 May 1980 Q453\>182. Don't make |\left| and |\right| delimiters too large; they need to be only 90\% of the enclosed size. [This eventually became |\delimiterfactor|.] @762 * 21 May 1980 G454. Add a new |\pagebreak| feature [later |\vadjust{\break}|]. @655 * 13 Jun 1980 # Today I'm beginning to overhaul the line-breaking routine, and I'll also install miscellaneous goodies. G455. Allow a radical sign to be in different font positions. @737 E456. Clear empty tokenlists off input stacks to allow deeper recursions (suggested by Jim Boyce's macros for chess positions). @325 G457. Make |\spaceskip| and |\parfillskip| changeable. @1228 G458. Add a new parameter |\rfudge| (per request of Zippel) [later |\mag|]. @288 G459. Add a new parameter |\loose| [later |\looseness|]; now parameters are allowed to take negative values. @875 E460. Remove the variable \\{just_par}. [Obsolete; it was the \\{real} equivalent of an \\{integer}]. * 14 Jun 1980 Q461. Install new line-breaking routines, including |\parshape|. (These major changes are introduced as Michael Plass and I write our article.) @813 G462. Add a new parameter |\exhyf| [later |\exhyphenpenalty|]. @869 * 16 Jun 1980 S463\>444. Change conventions in \\{eqtb} so that glue is distinguishable from other equivalents. @275 A464\>444. Don't expand |\b| in |\xdef{\d\b{...}}| after |\let\d=\def|. [Obsolete.] D465\>444. Avoid creating dead storage when doing \\{unsave} in certain regions. @275 * 17 Jun 1980 C466. Allow negative dimensions in rules. @138 * 19 Jun 1980 B467\>463. Make the new test for glue at the outer level of \\{show_eqtb}. @252 * 27 Jun 1980 Q468\>453. Don't let |\left| and |\right| become too small for big matrices. [This eventually became |\delimitershortfall|.] @762 * 3 Aug 1980 Q469. Don't move extra-wide, numbered equations flush left unless they begin with glue. @1202 * 15 Sep 1980 M470\>461. Say `$\ge\\{fz}$' instead of `$>\\{fz}$' in the pre-hyphenation routine; I'd forgotten my definition of \\{fz} [a variable used to test for a sequence of lowercase letters in the same font]. @897 R471\>395. Check the range of the index in |\chcode| before saving the old value. @1232 * 18 Sep 1980 D472\>457. Don't forget to increase the reference count to |\parfillskip|, or it will mysteriously vanish. @816 * 19 Sep 1980 C473\>412. Make leaders break like glue in both horizontal and vertical modes. @149 Q474\>364. Make |\mathsurround| break properly at left and right end of lines. @879 * 13 Oct 1980 I475\>461. Remove spurious overfull boxes generated when the looseness criterion fails. [Obsolete.] A476\>461. Redesign the iteration for looseness; breakpoints were not chosen optimally. @875 E477\>461. Avoid storing a lot of breakpoints when they are dominated by others. @836 B478\>366. Don't say `\\{cur_node}' when you mean `\\{mem}[\\{cur_node}]'. @1105 Q479\>461. Prefer the oldest break to the youngest break when two break nodes have the same total demerits. @836 L480\>461. Don't make badness too big for floating-point calculations, when forced to make an overfull box. [Obsolete.] * 10 Dec 1980 R481. Make it impossible to get unmatched `|}|' in a delimited macro argument. @392 G482. Add new |\topsep| and |\botsep| features. [These are \TeX78's way to put space at the edge of inserts, replaced in \TeX82 by the |\skip| register corresponding to an |\insert| class.] @1009 * 6 Jan 1981 P483. Install new routines for reading the font metrics, using Ramshaw's |TFM| files instead of\/ |TFX| files. @539 I484. Abort after reporting 100 errors, if not pausing on errors. @82 G485. Add new |\spacefactor| and |\specskip| and |\skip| primitives. [At this time we write `|\specskip3=10pt|' and `|\skip3|' for what will become `|\skip3=10pt|' and `|\hskip\skip3|' in \TeX82.] @1060 G486\>366. |\unskip| is now allowed in internal vertical mode. @1105 * 26 Jan 1981 B487\>482. Don't say `\\{mem}[$q$]' when you mean `$q$'. (See \#143 and \#478.) @1009 * 27 Feb 1981 I488\>417. Put some linefeeds back into the transcript file, in order to prevent overprinting in listings. [System dependent.] G489. Add a new |\dpenalty| feature [later |\postdisplaypenalty|]. @1205 G490. Add the dimension |cc| for European users. @458 C491. Make \\{scan_keyword} match uppercase letters as alternatives to lowercase ones (suggested by Barbara Beeton's experiments with |\uppercase|). @407 I492. Add nonstop mode so that overnight batch processing is possible. @73 * 2 Mar 1981 S493\>422. Fix a still more serious |\gdef| bug: The generality of\/ |\gdef| almost makes it a crime to forget {\sl any\/} control sequence names, ever! (The previous bug was only the tip of an iceberg.) @259 I494. Issue warning message at the end of a file page if nesting level isn't zero. [System dependent.] * 5 Mar 1981 I495. Keep track of maximum memory usage, for statistical reporting. [Obsolete.] @125 Q496\>350. Prune away glue and penalties at top of page after marks, sends, inserts. @1000 G497. Allow |\mark| in horizontal mode. [Later it will be |\vadjust{\mark...}|.] @655 C498. Allow optional space before a required left brace, e.g., |\if AA {...}|. [See \#251.] @403 I499. Issue an incomplete |\if| error, to help catch a bad |\if|. @336 * 17 Mar 1981 I500\>494. Omit the warning message at end of a file page unless the nesting level has changed on that page. [System dependent.] Q501\>310. Fix the spacing when there is a very tall subscript with a superscript. @759 * 20 Mar 1981 S502\>371. Make space-eating after |\else| fully consistent between the true and false cases. [Obsolete.] * 24 Mar 1981 B503\>496. Change \\{glue_spec_size} to \\{ins_spec_size} in \\{vpackage} [where insertions are done]. [Obsolete.] * 5 Apr 1981 B504\>501. Fix a typo (`|+|' instead of `|-|') in the new subscript code; this shifted certain subscripts down instead of up. @759 * 18 Apr 1981 G505. Make leaders with rules of specified size act like variable rules. @626,635 * 29 Apr 1981 A506\>461. Don't consider $\\{badness}>\\{threshold}$ at a line |\break| except in an emergency. @854 * 13 Jul 1981 C507\>402. Allow other characters as numbers. @442 R508\>294. Avoid dead storage if a \\{no_new_control_sequence} error occurs. [Obsolete.] @259 G509. Add a new |\ifx| feature. @507 G510. Add new features |\xleaders| and |\cleaders|. @626,635 * 14 Jul 1981 S511\>507. Amend the new code for constants; the `|.|' in `|.5|' is thought to mean \O{056}! @442 L512\>507. And fix an egregious blunder in that code: New commands at the end of a procedure are ignored when earlier statements exit via {\bf return}. @442 * 4 Aug 1981 P513. Accept alphabetic codes for all online error recovery options, instead of insisting on control codes like line feed or form feed. [The original error-recovery codes were suggested by the conventions of the |SAIL| compiler.] @84 G514. Add a new |\thebox| feature [later |\lastbox|]. @1079 * 7 Aug 1981 G515. Add |fil|, |fill|, and |filll| as units for glue stretching or shrinking. @454 I516. Suppress the overfull box error when shrinkage amount is negative. @664 * 9 Aug 1981 Q517. Let unset boxes inherit the size of their parent in alignments. @810 * 12 Apr 1982 F518. Make |INITEX| dump out the \\{font_dsize} array needed by the new |DVI| output module. @1322 * 1 May 1982 S519\>151. Fix \\{clean_box} so that \\{mlist_to_hlist} cannot make $\\{link}(q)=0$ and $\\{type}(q)=\\{glue_node}$. @720 # [That was the historic final change to \TeX78. All subsequent entries in this log refer to \TeX82.] * 15 Jul 1982 # Finished draft of test program and began debugging about 1430 [2:30\thinspace pm]. Taking my time. BX1. Change \\{eqtb}[\\{cur_font}] to \\{eqtb}[\\{cur_font_loc}]. @232 # Not logging changes to the exposition. # Compile time is about 2 minutes CPU, times 5 for time-sharing; add another half minute for linking and loading. # Hash table and \\{get_next} seem to be working, with no changes needed! # Time out 1630--1815 for Jill's birthday party. LX2. Insert {\bf begin} \dots~{\bf end} around \\{dump_int} macro. @1305 IX3. Print two blank spaces before date in \\{open_log_file}. @536 AX4. Update $x$ and \\{var_used} outside the {\bf for} loop. @1311 BX5. Change {\bf if} $=$ to {\bf if} $\ne$ as loop exit condition. @1315,1316 # The |TRIP| test should preload more fonts. LX6. Insert {\bf begin} \dots~{\bf end} around statistics output. @1334 FX7. Must \\{get_x_token} when scanning a number. @445 IX8. Interactive \\{debug_help} needs to print a newline. @1338 FX9. Include \\{ignore_spaces} and \\{math_accent} in \\{print_cmd_char} cases. @266 IX10. Don't call \\{confusion} when \\{print_cmd_char} sees unknown code. @298 # Compiler bug causes stack overflow. Retiring for the night at 2145. * 16 Jul 1982 # Starting at 0700; DRF has fixed the compiler. RX11. Allow arbitrary integer parameters in diagnostic print routines. @237,699 TX12. Say \\{cur_tok}, not \\{cur_val}, when you mean \\{cur_tok}. @440 FX13. Make |\pause| effective also on first line of a file. @538 FX14. Show context after online deletion. @88 IX15. Bypass reference count when \\{debug_help} shows a token list. @1339 BX16. Change `{\bf case} $p$' to `{\bf case} \\{type}($p$)'. @1000 FX17. Fix timing of \\{print_ln} when scrolling help messages. @90 PX18. Make \\{other_char} the default category for ASCII control codes too. @232 AX19. Use special scanning method for font number in \\{new_font}. @1257 # Eating lunch, 1020--1035, while the machine slowly recompiles everything. FX20. Don't forget to increase $k$ in the {\bf while} loop. @355 DX21. Adjust \\{limit} properly after line changed when pausing. @363 FX22. Remember to return a value in \\{new_spec} and \\{new_penalty}. @151,158 # Now stepping through \\{line_break} in simple case. AX23. Don't prune unwanted nodes if $\\{cur_p}=\\{null}$. @877 FX24. Print a closing parenthesis when displaying glue nodes. @189 SX25. Use \\{last}, not \\{limit}, in \\{term_input}; else error prompt causes trouble when $\\{state}=\\{token_list}$. @71,87 DX26. Set $\\{first}\gets\\{limit}+1$ after \\{init_terminal}. @331 DX27. Make sure \\{set_trick_count} is always performed. @317 * 17 Jul 1982 IX28. Add new diagnostic feature |\tracingcommands|. @299,1031 # Debugging of system-dependent code not shown in this log. # Tangling \TeX\ now takes 1.75 minutes; about 75K bytes, 108K tokens. # Redundant semicolon sends Pascal compiler into infinite loop! FX29. Initialize $\\{passive}\gets\\{null}$. @864 AX30. Fix pseudoprinting when the line is empty. @318 EX31. Merge adjacent free areas of dynamic memory before dumping. @131 FX32. Print the word |mode| in \\{print_mode}. @211 IX33. Improve message and help in case of weird error. @415 GX34. Allow optional space after |\def| and similar constructions. @473 MX35. Declare \\{alpha} to be integer in \\{read_font_info}. @560 AX36. Fix timing of \\{back_input} in \\{scan_dimen}. @448 IX37. Back up after missing number error. @446 IX38. Show the `|at|' size that is considered improper. @1259 IX39. Streamline the dialog in \\{debug_help}. @1338 MX40. Take output of \\{the_toks} from the advertised place. @467,1297 TX41. Say \\{trie_fix}($q$), not \\{trie_fix}($p$). @959 SX42. Decrease low limit of \\{error_count} to $-1$. @76 * 18 Jul 1982 FX43. Clear initial reference count of macro definitions. @473 AX44. Fix timing of \\{back_input} in \\{scan_glue}. @461 BX45. Use \\{cur_val_level}, not \\{cur_val}, when checking levels. @461 BX46. Multiply |fil| units by $2^{16}$ for correct scaling. @454 BX47. Don't confuse \\{glue_base} with \\{skip_base}. @1237 AX48. Fix \\{print_scaled} so that 0.01 doesn't come out |0.1|. @103 IX49\>X28. Show mode changes when tracing commands. @299 LX50. Don't say {\bf if} $(n=0)\lor(\,\ldots\;\hbox{\bf div}\;n)$ in Pascal. @105 BX51. Don't confuse \\{box_flag} with \\{box_code}. @1075 SX52. Reset \\{offset} on \\{print_ln} even in \\{no_print} mode. @57 SX53. Fix restarting of interrupts after \\{big_switch}. @1031 LX54. Don't loop {\bf for} $k\gets a$ {\bf to} $b-1$ when $b=0$ if $k$ is declared nonnegative. IX55. Put `|=|' sign into the \\{format_ident}. @1328 SX56. Allow $r$ to be any integer in \\{get_node}. @125 IX57. Don't put the output of \\{print_file_name} in quotes. @518 IX58. Say `|dumped|' after dumping. @1311 EX59. Eliminate unnecessary initialization code. @1332 LX60. Get the file reading started right when beginning to undump. @1308 IX61. Give forlorn message if format file can't be loaded. @1303 FX62. Assign value to \\{cur_val} after glue arithmetic. @1239,1240 * 19 Jul 1982 LX63. Don't say {\bf if} $p>\\{max}\lor\\{free}[p]$ in Pascal. @169 AX64. Fix memory-undump logic; loops are out of phase with input. @1312 BX65. Undump \\{hyph_word}[$j$], not \\{hyph_word}[$k$]. @1325 # At last |trip.fmt| loads without bombing out. PX66. Remove assignment of array to array, not allowed by IBM Pascal (Susan Plass). @167 PX67. Simplify an expression that's too big for IBM Pascal (Susan Plass). @1009 AX68. Go to \\{contribute}, not \\{done}, after insertions. @1000 IX69. Decrease \\{depth_threshold} if there's not enough string space. @198 IX70. Show rules as `{\tt\char`\|}' in short displays. @175 IX71. Don't show null glue in short displays. @175 SX72. Set $\\{job_name}\gets0$ as part of output initialization. @528 SX73. Don't complain of infinite shrinkage on |0pt minus 0fil|. @825,976,1009 IX74. Use different prompt at beginning when accepting a file name. @37 FX75. Reset \\{last_glue} on nonglue nodes. @996 BX76. Remember to call \\{error} after printing |OK|. @1293 LX77. Insert {\bf begin} \dots{ \bf end} around program text of section. @1025 FX78. Define the |\shipout| primitive. @1071,1073 AX79. Introduce \\{write_loc} analogous to \\{par_loc}. @1344,1371 FX80. Dump and undump \\{par_loc} and \\{write_loc}. @1313,1314 FX81. Allow \\{the} in \\{scan_the} [later \\{scan_something_internal}]. @413 EX82. Interchange command codes $\\{the}:=:\\{number}$ [later \\{convert}]. @210 BX83. Don't confuse \\{breadth} with \\{depth}. @236 IX84. Add string printing feature to \\{debug_help}. @1339 FX85. Set $\\{state}\gets\\{mid_line}$ in \\{begin_file_reading}. @328 # Time out 2105--2200 to pick up Jenny from driving lesson. LX86. Keep $c\le127$ when deleting 99 tokens. @88 SX87. Don't check for \\{str_room} error when $\\{selector}=\\{new_string}$. @1328 * 21 Jul 1982 IX88. Gather more statistics: String usage, font info, hyphen exceptions, stacks. @1334 DX89\>X79. Initialize \\{write_loc} from \\{cur_val}, not from \\{cs_ptr}. @1344 FX90. Remember to pack file name for |\open|. @1374 SX91\>X34. Defuse |\outer| test before scanning optional space after `|}|'. @473 SX92. Don't allow \\{prepare_mag} to cause errors after \\{jump_out}. @84 # The first page of |DVI| output is {\sl perfect\/}! Pause to play piano. BX93. Don't confuse \\{dimen_base} with \\{scaled_base}. @1237 DX94. Initialize $\\{link}(\\{page_head})\gets\\{null}$ when beginning a page. @991 SX95. Correct \\{cur_height} more often, since \\{max_depth} might be negative. @972,973 AX96. Calculate page dimensions properly after vertical kerns. @973 SX97. Install new \\{page_contents} logic to handle interaction between insertions and |\topskip|. @987,1008 SX98. Allow \\{top_skip} glue to be a valid breakpoint. @1001 FX99. Don't forget to count \\{dyn_used} in inner loop [erroneous analysis retracted later]. @1034 FX100. Set $p\gets q$ after migration step. @655 FX101. Clear \\{prev_graf} to zero at start of paragraph. @1091 LX102. Put parens into negated \\{leader_flag} macro. @1078 # Time out 1720--1920 for John's birthday dinner. DX103. Scale \\{best_height} when adjusting \\{page_goal}. @1010 AX104. Simplify logic of split insertions; three states become two. @981,1019,1020 MX105. Don't omit first character when showing a macro argument. @400 RX106. Prevent clobberage if macros have too many parameters. @390 * 22 Jul 1982 IX107. Tell how many |DVI| bytes were output. @642 IX108\>X88. Adjust for singular or plural statistics. @1320,1334 SX109\>X98. Consider \\{page_head} a glue node, to inhibit unwanted break. @988 DX110. Introduce \\{new_skip_param} to keep reference counts updated. @679,969,1001 DX111. Record the correct size of new insertion after it's split. @1010 DX112. Use \\{free_node}, not \\{flush_node_list}, when recycling insertion nodes. @1022 SX113. Make online insertions work after \\{get_next} is interrupted. @87,324,343 BX114. Print newline on interruption stop. @98 SX115\>X34. Put space before \\{end_write_token}. @1371 BX116. Don't confuse \\{glue_order} with \\{stretch_order}. @838 TX117. Set $\\{max_dimen}\gets\hbox{\it'7777777777\/}$, not {\it'777777777}. @421 MX118. Make |\global\textfont| legal. @1211 BX119. Fetch |\the\textfont| with \\{equiv}, not \\{fam_font}. @415 BX120. Call $\\{new_ligature}(f,l,\ldots)$ not $(f,c,\ldots)$. @1035 RX121. Make \\{show_box} work on random garbage. @174,177 DX122. Count reference to \\{zero_glue} from \\{cond_math_glue}. @1171 * 23 Jul 1982 RX123. Allow $\\{avail}=\\{null}$ when undumping. @1312 BX124\>X110. Set $\\{width}(\\{glue_ptr}(p))$, not $\\{width}(p)$. @679 AX125. Put \\{begin_file_reading} inside the \\{start_input} loop. @537 BX126\>X116. Don't confuse \\{glue_stretch} with \\{stretch_order} [the previous fix went only half\-way]. @838 BX127. Negate $x$ when calculating badness of shrinkage. @667,678 LX128\>X121. Remove dangling {\bf else} that parses wrong. @174 IX129\>X28. Print newline before |{|, not after |}|, when tracing commands. @299 IX130. Remove colon from overfull box messages. @663,675 DX131\>X97. Compute \\{page_goal} properly when the first box arrives after inserts. @1001 BX132. Don't confuse \\{page_size} [now \\{page_goal}] with \\{best_size}. @1017 AX133. Put heldover insertions at front of contribution list. @1023 SX134\>X88. Output stats before closing |DVI| file, since the latter decreases \\{font_ptr}. @1333 TX135. Don't call a |\vbox| an |\hbox|. @674 TX136. Fix misplaced {\bf end} caused by editing error. @675 * 24 Jul 1982 DX137. Don't \\{eq_destroy} any paragraph shape when \\{par_shape} is null. @275 IX138. Omit blank before |\message| at the beginning of a line. @1280 AX139\>X104. Don't try to split an insertion when \\{best_node} isn't the split one. @1021 LX140. Correct another case of `{\bf if} $x\land y$' misunderstood by Pascal. @1021 IX141. Provide diagnostic info about insertions via |\showlists|. @986 IX142. Add `|inside a group|' to clarify a warning message. @1335 IX143. Report \\{prev_depth} on a separate line in |\showlists|. @219 SX144. Back up input to avoid unexpected clobberage of \\{cur_tok}. @1090 # Wow what a bug: \\{new_graf} calls \\{build_page}, which invokes the output routine, after which `\/{\bf goto} \\{reswitch}' is a {\sl disaster}. DX145. Add insertion glue to \\{page_so_far} instead of subtracting it from the goal. @1009 IX146. Put extra blank line before overfull box warning. @660 CX147. Define break at kern consistently between horizontal and vertical lists. @973,1000 DX148. Renumber so that math nodes are nondiscardable. @147 TX149. Correct the \\{char_kern} macro: |#|, not $f$. @557 FX150. Decrease $l$ after reconstituting discretionary break. @916 EX151. Simplify the hyphen routine, knowing that $\\{link}(s)=\\{null}$. @918 FX152. Initialize $r\gets q$ in discretionary destruction routine. @883 * 25 Jul 1982 AX153. Don't add interline penalty after last line of paragraph. @890 IX154. Adjust spacing in diagnostic messages. @245 DX155. Avoid simultaneous use of \\{temp_head} by \\{prune_page_top} and the page builder. @1017 FX156. Clear the \\{post_break} field of simple discretionaries. @916 AX157. Split \\{offset} into independent variables \\{term_offset}, \\{file_offset}. @54,57,58 # Am freezing current program as version $-0.25$; a week of TUG lectures begins tomorrow. * 5 Aug 1982 IX158. The `|.err|' file should be `|.log|' instead. @534 GX159. Allow |\special| strings to contain more than 256 bytes. @585,1368 MX160\>X99. Undo ``correction'' to a non-bug. @1034 IX161. Suggest |\&| in help message for unexpected |&|. @1128 GX162. Make `|E|' a standard option for exiting. @84 GX163. Restore the use of dead cycles \`a la \TeX78. @1024,1054 # The previous six changes were suggested during discussions with \TeX82 class. SX164. Fix global variable conflict between \\{open_log_file} and \\{new_font}. @1257 CX165. Allow optional `|=|' when assign to font parameter. @1253 FX166. Set \\{cur_val} after increasing the number of font parameters. @580 DX167. Set \\{hash_brace} when matching `|{|'. @476 IX168\>X88. Clarify meaning of statistics printed. @1334 GX169. Change |DVI| format to include design size. @602,1260 DX170. Introduce \\{def_ref} for \\{runaway} messages. @306 MX171. Restore \\{cur_cs} before calling \\{scan_toks}. @1226 AX172\>X157. Update \\{print_nl} to dual offset conventions. @62 AX173\>X163. Move endgame logic inside \\{main_control}, because the output routine becomes active. @1054 * 6 Aug 1982 CX174. Allow |INITEX| to load format files. @1337 EX175. Conserve input stack space by deleting finished token lists. @325 IX176\>X74. Print the opening `|**|' in the transcript file. @534 # Now ready to try breaking new ground in |TRIP|. SX177. Preserve \\{align_state} from tokens deleted online. @88 DX178. Set $t$ in all branches of \\{scan_toks}. @473 SX179. Change `$\\{cur_cmd}\le\\{right_brace}$' to `$\\{cur_tok}\le \\{right_brace_limit}$'; otherwise |\relax| gets through. @477 CX180. Allow optional |=| when setting |\spacefactor|; disallow zero. @1243 BX181. Change \\{vpackage}(\\{head}) to \\{vpackage}(\\{link}(\\{head})). @796 # Shades of 1978! LX182. Insert missing {\bf begin} \dots{ \bf end}. @798 * 7 Aug 1982 LX183. Keep \\{trie_max} declared in non-|INITEX| [later rescinded]. @950 DX184. Watch out for empty token list when copying. @466 DX185. Free unused reference count slot when defining |\everypar|. @1226 GX186\>X163. Introduce |\maxdeadcycles|. @1012 # I believe the \\{line_break} routine has passed its test perfectly. SX187. Don't put discretionary after |-| inside a discretionary. @1039 CX188. Change `|\minus|' to `|\minusthe|' [this feature retracted later]. @413 BX189. Change \\{cur_p} to $r$ (three places). @875 AX190. Increase range of \\{hc} to \\{halfword}; otherwise end-of-word mark might match a vacant entry in the trie. @892 FX191. Initialize $b$ in \\{shift_case} routine. @1288 EX192. Don't back up if a space follows a decimal fraction. @452 BX193. Don't confuse \\{glue_base} with \\{dimen_base}. @1145 LX194. Guard against anomalous floating-point values in glue display. @186 * 8 Aug 1982 SX195. Avoid infinite loop when |\outer| leads to runaways. @339 # I worked on that problem about two hours before fixing it. IX196. Move final \\{debug_help} to \\{succumb}, except in batch mode. @93 RX197. Insert kern after spanned box, to defeat access to floating point. @808 * 9 Aug 1982 CX198. Include |\leftskip| and |\rightskip| in displayed equations [rescinded later]. @1199 IX199. Trace line-break computations if $\\{tracing_stats}>2$. @846,856 DX200. Keep \\{prev_p} up to date when passing a string. @867 # Now stepping through math stuff; a lot is working. DX201. Set $\\{link}(p)\gets z$ when making a fraction. @747 CX202. Don't reset space factor when beginning |\valign|. @775 IX203. Don't show glue setting if $\\{glue_sign}=\\{normal}$. @186 DX204. Clear \\{glue_stretch} and \\{glue_shrink} when creating an unset box. @801 BX205. Do \\{vpack} in hmode and vice versa when aligning. @804 AX206. Remove fallacious call to \\{confusion} after alignment in display. @1206 AX207. Don't test $\\{mode}=\\{vmode}$ in display, test $\\{nest_ptr}=1$. @1145 FX208. Show an \\{inner_noad} as well as the other types. @690,696 DX209. Renumber \\{mu_glue} and \\{cond_math_glue} so that the glue display logic works. @149 BX210. Don't confuse \\{cur_size} with \\{cur_style}. @703 FX211. Advance $p\gets q$ during second pass over mlist. @761 IX212. Add helpful hint about |\tracingonline=1|. @1293 TX213. Delete spurious statement left from sloppy editing. @710 DX214. Change the subtype when \\{mskip} becomes \\{hskip}. @732 FX215. Don't forget to use the remainder when computing math glue. @716 IX216\>X199. Improve paragraph diagnostics using \\{short_display}. @857 IX217\>X199. Introduce \\{artificial_badness} for better diagnostics. @854,856 * 11 Aug 1982 AX218. Introduce \\{char_box} subroutine so that \\{var_delimiter} adds italic correction. @709 SX219. Save font and char in local variables of \\{make_math_accent}, since it can be recursive. @738 FX220. Call \\{error} after decrying an invalid character. @346 * 12 Aug 1982 IX221\>X199. Install new format for showing break nodes. @846 # I have been testing \\{line_break} and I think it's working fine. BX222. Change $q$ to $p$, in order to catch empty alignments. @812,1206 SX223. Disallow third part of discretionary in math mode. @1120 DX224. Don't change \\{tail} if discretionary third part is empty. @1120 IX225. Say |nonscript|, not |non_script|. @189 SX226. Inhibit math if |\scriptfont3| is improper. @1195 IX227\>X199. Introduce {\tt\@}|firstpass| and {\tt\@}|secondpass| comments. @863 TX228. Change $p$ to $r$ when you mean $r$. @1204 IX229\>X108. Say |page|, not |pages|, if there's only |1|. @642 IX230. Insert space before |[]| on truncated |\showlists|. @182 * 28 Aug 1982 # Back from vacation after having looked at hardcopy listing of |TRIP| test. GX231. Allow |dm| as a unit [later |.5dm1| will be |.5\dimen1|]. @455 IX232\>X108. Singularize |prevgraf 1 lines|. @219 IX233. Omit trailing zero count registers when showing completed page numbers. @638 LX234. Avoid clobbering $a$ by introducing a new local variable $t$. @986 DX235\>X216. Fix diagnostic printing of discretionaries. @858 IX236. Don't show unset stretch/shrink that's zero. @185 CX237\>X198. Make |\halign| in displays consistent with other displays. (Namely, ignore |\leftskip| and |\rightskip| in nonaligned displays; respect the paragraph shape in aligned displays.) @800,1199 IX238. Parenthesize `|If you're confused ...|'. @403 IX239. Say `|\fraction|', not `|\xabovex|'. @697 FX240. Remember to {\bf return} when you should. @1153 PX241. Use absolute value to make sure {\bf div} is unambiguous. @737 BX242\>X218. Don't confuse depth with height. @709 BX243. Use $\\{delta}-\\{height}$, not $\\{height}-\\{delta}$. @736 BX244. Increase \\{shift_down} to increase the clearance. @745 IX245. Don't back up after improper use of |\the|. @428 IX246. Don't give |0pt| as the default result when looking for \\{tok_val}. @428 FX247. Initialize \\{second_indent} in the easy case. @848 FX248. Package the equation number. @1204 QX249. Don't resort to $v\gets\\{max_dimen}$ when glue doesn't stretch or shrink. @1148 IX250. Insert newline before showing current |\botmark|. FX251. Call \\{error} after giving error message. @784 AX252. Change implementation of |\number|; it should \\{scan_int}, not something internal. @471 PX253. Introduce symbolic constants like \\{format_area_length}. @524 PX254. Change \\{quit} to \\{jump_out}, since some compilers treat \\{quit} as a reserved word. @81 LX255. Add more parentheses to get proper parsing. @1260 IX256. Say |please| in order to be friendly (or at least polite). @360 BX257. Don't confuse \\{cur_vcmd} with \\{cur_chr}. @508 IX258. Use |&| instead of |!| to specify a preloaded format. @1337 TX259\>X177. Correct |s3| to |s4|. @88 GX260. Introduce new primitive |\mathchardef|, to save space and time. @1224 CX261. Use the |[]| convention for noads as well as nodes. @692 TX262. Correct spelling in call to \\{primitive}: |\xatopx| should be |\xoverx| [later renamed, thank goodness]. @1178 * 30 Aug 1982 RX263. Don't fetch \\{link}(\\{null}) in malformed list. @175 SX264. Initialize \\{align_state} at a better time so that \\{align_peek} doesn't see |&| or |\span|. @785,791 SX265. Outlaw preamble interfering with $\\{align_state}=0$. @789 CX266. Add level of grouping to alignment to tabskip locality. @774 FX267. Check \\{align_state} when scanning $\langle u_j\rangle$. @783 AX268. Move `\\{unsave}; \\{new_save_level}' from \\{main_control} into \\{fin_col}. @791,1131 SX269\>X180. Remember \\{cur_chr} when you're looking for optional `|=|'. @1243 TX270. Change $q$ to $r$ [in code now obsolete]. @804 IX271. Disable interrupts during \\{back_error} so that help messages aren't clobbered. @327 SX272. Introduce \\{slow_print} for printing control sequences. @60 IX273. Initialize \\{del_code}(|"."|$)\gets0$ for error recovery. @240 SX274. Call \\{end_file_reading} before calling \\{check_outer_validity}. @362 IX275. Don't delete an extra `|}|' when |\par| will help find a runaway. @395 * 31 Aug 1982 BX276. Don't confuse \\{thin_muskip} with \\{thin_muskip_code}. @413 FX277\>X266. Recover from error if new \\{align_group} ends abnormally. @1132 IX278. Recover from error if |\par| occurs when $\\{align_state}<0$. @1094 CX279. Make |\hskip\the\thinmuskip| and |\mskip\the\baselineskip| erroneous. @413 GX280. Add |\muskip| and |\setmuskip| analogs to |skip| and |\setskip|. @413,1228 EX281. Don't output |pop| right after |push|. @601 # The |TRIP| test looks right; now to test for wasted memory. # When memory should be empty I find $\\{dyn_used}=18$, $\\{var_used}=267$. * 1 Sep 1982 # Made special |MEMTEX| program, designed to track all memory allocation. DX282. Delete reference to \\{last_glue} when a page is packaged. @1017 IX283. Include \\{save_stack} in the \\{search_mem} debugging routine. @285 CX284. Disallow |\vfill| in restricted horizontal mode. @1095 # Most of the memory locations I thought were wasted were actually in good use. # Total 192 hours (approx) debugging time so far since July 15. * 2 Sep 1982 # Now looking at all zero counts in profile and extending |TRIP|. EX285. Simplify the creation of |vtop| boxes. @1087 CX286. Set $\\{space_factor}\gets1000$ after |\hbox|. @1076 PX287. Introduce preamble into |DVI| format. @617 SX288. Give special \\{chr_code} to |\relax|. @265 IX289. Don't show `|(null)|' when token list is null, just show nothing. @295 EX290. Delete the procedure \\{write_name_string}, which is never used. CX291. Rename |\xabovex| to |\abovewithdelims|; do the same for |\xatopx| and |\xoverx|. @1178 QX292. Improve \\{clean_box} so that it recognizes cleanliness better. @720 IX293. Report a |Missing delimiter| more meaningfully. @1161 RX294. Give \\{endv_token} a \\{chr} code of 128 so that it will end a file name. @289 RX295. Test present of math fonts {\sl after\/} parsing an mlist, not before. @1138,1195 IX296. Omit `|recent contributions|' and/or `|current page|' when they are empty. @218,986 IX297. Display what \TeX\ has deleted after improper discretionary list has arisen. @1121 IX298. Show what math character was undefined. @723 IX299. Improve the |Incompatible magnification| error; break it into two lines. @288 DX300. Put new cases into \\{flush_node_list}, to recycle mlist noads. @698 * 6 Sep 1982 FX301\>X300. Insert a necessary `{\bf goto} \\{done}' in that new material. @698 # It took two hours to diagnose that {\bf goto} problem. TX302\>X295. Change `|2|' to `|3|' in help message for extension fonts. @1195 IX303. Add a special note if material is being held over for the next output. @986 RX304. Divide before multiplying in \\{make_left_right}, to avoid overflow. @762 IX305. Introduce the \\{box_error} routine. @992 FX306. Clear \\{arith_error} after overflow has been reported. @460 BX307\>X249. Don't confuse \\{stretch} with \\{glue_stretch}. @1148 DX308. Set $\\{glue_sign}\gets\\{normal}$ when packaging with glue ratio zero. @558,664 AX309. Test for overflow before attaching the sign. @448 # That all worked! Now trying |min_quarterword| negative. LX310. Take absolute value before applying {\bf mod} in \\{new_trie_op}. @944 LX311. Say $\\{qi}(c)$, not $c$, when testing |TFM| flags [now obsolete]. @573 LX312. Initialize \\{token_ref_count}(\\{def_ref}) to \\{null}, not zero. @473 LX313. Change the type of \\{vsplit} parameter $n$ from \\{quarterword} to \\{eight_bits}. @977 LX314. Initialize \\{null-delimiter} different form \\{null_character}. @685 LX315. Insert \\{qi} twice in \\{scan_delimiter}. @1160 FX316. Insert \\{qi} in \\{scan_math}. @1151 FX317. Insert \\{qo} in \\{fetch}. @722,723 FX318. Insert \\{qi} in \\{set_math_char}. @1155 FX319. Insert \\{qi} in \\{math_ac}. @1165 FX320. Insert \\{qo} in \\{mlist_to_hlist}. @755 IX321. Use brackets around 8-bit characters in \\{print_ASCII}. @68 IX322. Include \\{hyph_list} in the \\{search_mem} debugging routine. @933 # Now compiling non-|INITEX| to try an industrial-strength version. LX323. Add {\bf return} to \\{final_cleanup}, because some Pascal compilers insist that each label be used. @1335 DX324. Compute \\{par_token} when undumping. @1314 * 11 Sep 1982 IX325. Emit newline before file name, if near end of line. @537 CX326. Define |\ifx| for arbitrary tokens. @507 * 12 Sep 1982 IX327. Don't ask users to type |x| twice before exiting. @84 GX328. Install new features |\openin|, |\read|, |\ifeof|, |\closein|; rename existing |\open|, |\send|, |\close| to be |\openout|, |\write|, |\closeout|. @209,313,1275 GX329. Install new feature |\expandafter|. @368 PX330. Change the default file area from `||' to `|TeXinputs:|'. @574 * 13 Sep 1982 GX331. Install new feature |\string|. @472 AX332. Remove spurious space printed by \\{sprint_cs}. @263 # All tests passed now! But when I played with the system I found another bug (undetected by |TRIP|): FX333. Set $r\gets s$ after matching macro parameter tokens. @397 * 16 Sep 1982 IX334\>X199. Introduce serial numbers in line-break records, improving readability and independence. @846 IX335. Don't abort when \\{file_name_size} is exceeded. @519 * 17 Sep 1982 IX336. Remove unwanted period from font capacity message. @567 * 18 Sep 1982 GX337\>X329. Make |\expandafter| more powerful by moving it from semantics to syntax [i.e., from stomach to mouth]. @368 * 19 Sep 1982 IX338. Improve error recovery for `|Missing number|'. @415 * 22 Sep 1982 QX339. Suppress italic correction between letters in math mode except in math fonts. @752 * 24 Sep 1982 PX340. Define $\\{null}=\\{mem_bot}$, not \\{min_halfword}, because there's a reference to \\{link}(\\{null}) in \\{try_break}. @115 DX341. Initialize $\\{str_start}[0]\gets0$. @47 IX342. Avoid blank space at beginning of line. @638 DX343. Set type of new box in math mode to \\{ord_noad}, not \\{inner_noad}. @1076 * 28 Sep 1982 # Here are the first changes made to the preliminary listing of \TeX82 that was published by the \TeX\ project earlier this month. F520. Insert the missing cases \\{letter} and \\{other_char} after \\{x_token} looks ahead. @1038 C521. Change `|\pause|' to `|\pausing|'. @236 D522. Reset \\{overfull_rule} when determining tabskip glue. @804 A523. Fix the logic for scanning |\ifcase| [in obsolete syntax---everything is still done with braces since `|\fi|' doesn't exist yet]. @509 * 30 Sep 1982 I524. Change |"0.0"| to |"?.?"| (suggested by DRF). @186 * 2 Oct 1982 Q525. Use conditional thin spacing next to `Inner' noads. @764 Q526. Make thick spaces conditional. @766 * 4 Oct 1982 P527. Increase \\{trie_size} from 7000 to 8000, because of Frank Liang's improved (but longer) hyphenation patterns. @11 * 6 Oct 1982 F528\>X330. Change the string lengths to match the new \\{\TeX_format_default}. @520 # Version 0 of \TeX\ is being released today! * 8 Oct 1982 B529. Fix a blunder: I decreased $h$ mod a quarterword when it should have been decreased mod \\{trie_op_hash_size} (HWT). @944 * 9 Oct 1982 P530\>X258. Fix a typo (`|!|' not `|&|') in the |WEB| documentation. @524 F531. Remember to call \\{initialize} if a different format was preloaded (Max D{\'\i}az). @1337 # Version 0.1 incorporates the above changes. * 12 Oct 1982 G532. Add the `|\immediate|' feature, by popular request. @1375 # Version 0.2 incorporates this (somewhat extensive) change. * 13 Oct 1982 P533. Introduce new |WEB| macros so that \\{glue_ratio} is more easily changed. @109 # I began writing {\sl The \TeX book\/} today: edited the old preface and searched in the library for quotations. * 14 Oct 1982 B534. Change the type of \\{hd} to \\{eight_bits}; it's not a \\{quarterword} (HWT). @649 S535\>X281. Revise the optimization of\/ |DVI| commands: It's not always safe to eliminate \\{pop} when the preceding byte is \\{push}, since |DVI| commands have variable length! (Embarrassing oversight caught by DRF.) @601 * 15 Oct 1982 C536. Test `$\\{prev_depth}>\\{ignore_depth}$', not `$\ne$'. @679 # Version 0.3 incorporates the above changes. * 16 Oct 1982 P537. Omit definition of \\{align_size}; it's never used (Bill Scherlis). @11 I538. Inhibit error messages when packaging box 255. @1017 * 21 Oct 1982 A539\>X145. Subtract $\\{width}(q)$ from \\{page_goal}, don't add it to $\\{page_so_far}[1]$. @1009 # Version 0.4 incorporates the above changes. * 22 Oct 1982 P540. Increase the amount of lower (variable-size) memory from 12000 to 13000, since the \TeX\ program listing now needs about 11500. [At this time there still is a fixed boundary between upper and lower memory.] @12 G541. Add a new parameter |\boxmaxdepth|. @1086 # Version 0.5 incorporates the above changes. * 26 Oct 1982 B542. Fix an off-by-one error caught by Gabi Kuper and HWT. (I forgot `${}+1$'). @1317 B543. Fix the spacing of displayed control sequences: \\{print_cs} should base its decision on $\\{cat_code}(p-\\{single_base})$, not $\\{cat_code}(p)$. @262 # The |TRIP| test detected this bug, but I didn't notice. * 27 Oct 1982 S544. Set \\{math_type} before saying $\\{fetch}(\\{nucleus}(q))$, since fetching can have a side effect. @752 * 28 Oct 1982 G545. Install a major change: Fonts now have identifiers instead of code letters. Eliminate the `|\:|' primitive, and give corresponding new features to `|\the|'. @209 # Actually I began making these changes on October 26, but I needed two days to debug them and to put Humpty Dumpty together again. # At this time I'm also drafting macros for typesetting {\sl The \TeX book}. # The above changes have been incorporated into Version 0.6. * 30 Oct 1982 # After years of searching, I've finally found a definitive definition of the printer's point; and (unfortunately) my previous conjecture was wrong. The truth is that $\rm83\,pc=35\,cm$, exactly; so I am changing \TeX\ to conform. C546. Revise unit definitions for the `real' printer's point. @458,617 # Version 0.7 incorporates the above. * 1 Nov 1982 # Oops! Retract error \#546, and retract \TeX\ Version 0.7; the source of my information about points was flaky after all. My original suppositions were correct, as confirmed by NBS Circular 570. * 4 Nov 1982 C547. Revise the definition of |dd|, conforming to the definitive value shown me by Chuck Bigelow. @458 R548\>545. Introduce ``frozen'' copies of font identifiers, to be returned by |\the\font|, so that font manipulation is more robust. @1257 * 5 Nov 1982 D549. Reset \\{looseness} and paragraph shape when beginning a |\vbox|. @1083 * 6 Nov 1982 D550. De-update \\{align_state} when braces are in constants. @442 I551\>X294. Improve error recovery for bad alignments. @1127 # Today I wrapped up Chapters 4 and 5. * 8 Nov 1982 G552. Give more power to |\let|: the right-hand side needn't be a control sequence. @1221 I553. Amend \\{show_context} to say `$(\\{base_ptr}=\\{input_ptr})\lor{}$'; otherwise undefined control sequences can be invisible in unusual cases (John Hobby). @312 A554. Compute demerits more suitably by adding a penalty squared, instead of adding penalties before squaring. @859 # Previously a slightly loose hyphenated line followed by a decent line was considered worse than a decent hyphenated line followed by a quite loose line. * 10 Nov 1982 E555. Save a bit of buffer space by declaring \\{pool_file} only in |INITEX|. @50 * 11 Nov 1982 I556. Introduce a new context indicator to clarify \TeX's scanning state: A special type called \\{backed_up} is distinguished from other kinds of \\{inserted} lists; it is called `recently read' or `to be read again', while others are called `inserted'. @314 I557. Append a comment, `|treated as zero|', to the missing-number message. @446 I558. Ignore the settings of\/ |\hfuzz| or |\vfuzz| if\/ |\hbadness| or |\vbadness| is less than 100. @666,677 * 13 Nov 1982 # Major surgery on the program is planned for today, because of new ideas suggested by correspondence with MDS and other macro writers. G559. Introduce a new |\tokens| register; this will be useful and easy to add, since \TeX\ already can handle |\everypar| and |\output|. @1227 C560\>X34. Change \\{get_x_token} to \\{get_token} when scanning an optional space; then a construction like |\def\foo{...}\foo| won't complain that |\foo| is undefined. @443 # This change was retracted when it was being debugged, because it could cause \\{endv} to abort the job. Then it was re-established again when I found that \\{endv} needed to be more robust anyway. [But it was eventually rescinded again.] G561. Make |\span| mean `expand' in a preamble. @782 E562. Use three separate {\bf if\/} tests instead of `$\land$' in the inner loop of \\{get_next}, to gain efficiency. @342 R563. Introduce \\{get_r_token} so that assignments have uniform error messages and so that frozen equivalents cannot be changed. @1215 # I gave a few variables more mnemonic names as I made these changes. C564. Move conditional statements from the semantics (`stomach') part of \TeX\ to the syntax (`mouth') part, by introducing `|\fi|'. Also introduce |\csname| and |\endcsname|. @372,489\hbox{--}500 # This makes macros much more predictable and logical, but it is by far the most drastic change ever made to \TeX. The program began to come back to life only after three days of solid hacking. # Several other things were cleaned up as part of this change because it is now more natural to handle them differently. For example, a null control sequence has now become more logical. # The result of all this is called Version 0.8. * 18 Nov 1982 # Today I resumed writing Chapter 8. Tomorrow I'm $\,2^{14}$ days old! * 21 Nov 1982 F565. Declare $c$ as a local variable for hyphenation (DRF). @912 E566. Omit the ``first pass'' and try hyphenations immediately, if\/ |\pretolerance| is negative (suggested by DRF). @863 R567. Don't ship out incredibly huge pages; they might foul up |DVI| files. @641 * 2 Dec 1982 G568. Add new features |\everymath| and |\everydisplay|. @1139,1145 G569. Add a new feature |\futurelet|. @1221 # The changes above have been incorporated into Version 0.9 of TeX. * 7 Dec 1982 G570. Add a new |\endinput| primitive (suggested by FY). @362,378 * 8 Dec 1982 I571. Try \\{off_save}, if\/ |\par| occurs in restricted horizontal mode. (This avoids embarrassment if \TeX\ says `type a command or say |\end|', then when you type |\end| it says you can't!) [However, I soon retracted this change.] @1094 * 21 Dec 1982 A572. Redefine |\relax| so that its \\{chr} field exceeds 127. (This facilitates the test for end in \\{scan_file_name}.) @265 F573\>566. Call \\{begin_diagnostic} when omitting the first pass of line breaking. @863 A574. Fix the logic of glue scanning: In |\hskip-1pt plus2pt| the minus should apply only to the |1pt|. @461 * 23 Dec 1982 I575. Renumber the decimal codes in paragraph statistics for loose and tight lines; they were ordered backwards. @817 C576. Treat a paragraph that ends with leaders like a paragraph that ends with glue. @816 C577. Allow commas as alternates to radix points, for Europeans. @438 C578. Change |\hangindent| to a normal dimension parameter. [It had been a combination of\/ |\hangindent| and |\hangafter|, with special syntax.] @247 G579. Make |\prevgraf| accessible to users. @422,1244 G580. Split |\clubpenalty| off from |\widowpenalty|. @890 # I'm typing Chapter 14 while making these changes. * 24 Dec 1982 S581. Use \\{back_input} instead of {\bf goto} \\{reswitch} when inserting |\par|, because |\par| may have changed. @1095 * 25 Dec 1982 # It's 10pm after a very Merry Christmas! I582\>X328. Don't prompt for a new file name if\/ |\openin| doesn't find a file. @1275 G583. Add a new |\jobname| primitive. @472 I584. Give the user a way to delete the dollar sign, when \TeX\ decides to insert one. @1047 C585. Allow optional equals after |\parshape|, and implement |\the\parshape|. @423,1248 * 26 Dec 1982 I586. Add an \\{if_line_field} to the condition stack entries, so that more informative error messages can be given. @489 D587\>549. Introduce a \\{normal_paragraph} procedure, since initialization is needed also within |\insert|, |\vadjust|, |\valign|, |\output|. @1070 * 27 Dec 1982 G588. Give users access to |\pagetotal| and |\pagegoal|. (Analogous to \#679 and \#585, but simpler.) @1245 I589\>X199. Introduce |\tracingpages|, allowing users to see page-optimization calculations. Also split |\tracingparagraphs| off from |\tracingstats|. @987,1005,1011 # The changes above have been incorporated into Version 0.91 of \TeX. * 31 Dec 1982 P590. Break the \\{build_page} procedure into two parts, by extracting the section now called \\{fire_up}. [This is necessary because some Pascal compilers, notably for IBM mainframes, cannot deal with large procedures.] @1012 S591\>564. Make |\ifodd1\else| legal by introducing \\{if_code}. @489 Q592. Improve alignments when columns don't occur: Don't append null boxes for columns missing before |\cr|, and zero out the tabskip glue after nonpresent columns. @802 I593. Make the error message about overfull alignment more intelligible. @801,804 # The changes above have been incorporated into Version 0.92 of \TeX82, which was the last version of 1982, completed at 11:59pm on December 31. * 3 Jan 1983 # Today I'm beginning to write Chapter 15, and planning the |\output| routine of |plain.tex|. C594\>X186. Change the logic of \\{its_all_over}; use \\{max_dead_cycles} here too, instead of the fixed constant~100. @1054 F595\>X34. Don't forget to \\{pop_nest} when an insert is empty. Also disallow optional space after |\insert|$\,n\,$|{...}|. @1100 * 4 Jan 1983 C596\>541. Use the |\boxmaxdepth| that's declared inside a |\vbox| when packaging it. @1086 C597. Rename |\groupbegin| and |\groupend| as |\begingroup| and |\endgroup|. @265 G598\>594. Make |\deadcycles| accessible to users. @1246 Q599. Base the split insertions on natural height plus depth, not on \\{delta}. @1010 # The changes above have been incorporated into Version 0.93. * 6 Jan 1983 D600. Add \\{push_math} to handle a case where I forgot to clear \\{incompleat_noad}. (This long-standing bug was unearthed today by Phyllis Winkler.) @1136 G601\>588. Add |\pageshrink|, etc., too. @1245 G602. Introduce new parameters |\floatingpenalty|, |\insertpenalties|. Also adopt a new internal representation of insertion nodes, so that |\floatingpenalty|, |\splittopskip| and |\splitmaxdepth| can be stored with each insertion. @140,1008 * 7 Jan 1983 Q603. Improve the rules for entering \\{new_line}, in particular when the end-of-line character is active. @343 * 9 Jan 1983 Q604. Distinguish between implicit and explicit kerns. @155,896 C605. Change the name |\ignorespace| to |\ignorespaces|. @265 C606\>560. Don't omit a blank space after |\def|, |\message|, |\mark|, etc.; the previous hodge-podge of rules is impossible to learn. @473 # The above changes appear in Version 0.94. * 12 Jan 1983 # Beginning to write the chapters on math today. G607. Add a new feature: active characters in math mode. @1151 * 15 Jan 1983 A608. Fix a surprise bug: `|$1-$|' treated the |-| as binary. @729 D609. Initialize \\{space_factor} inside discretionaries. @1117 * 16 Jan 1983 F610. Fix an incredibly embarrassing bug: I forgot to update \\{spotless} in the \\{error} routine! # While fixing this, I decided to change \\{spotless} to a more general \\{history} variable, as suggested by IBMers who want a return code. @76,82,1335 I611. Replace two calls of \\{confusion} by attempts at error recovery, in places where `|This can't happen|' could actually happen. @1027,1372 * 18 Jan 1983 R612. Introduce the \\{normalize_selector} routine to protect against startup anomalies when the transcript file isn't open. Also make \\{open_log_file} terminate in some cases. @92,535 R613\>591. Insert |\relax|, not a blank space, to cure infinite loop like |\ifeof\fi| (LL). @510 G614. Change the old |\limitswitch| to |\limits|, |\nolimits|, and |\displaylimits|. Incidentally, this fixes a bug in the former positioning of integral signs. @682,749 C615. Give a |\char| in math mode its inherited |\mathcode|. @1151 Q616\>525. Make underline, overline, radical, vcenter, accent noads and |{...}| all revert to type Ord instead of type Inner. Introduce a new primitive |\mathinner|. (This fixes the spacing, which got worse in some ways after change \#525.) @761 # I'm working on Appendix G today. * 19 Jan 1983 G617. Introduce a |\mathchoice| primitive. @1174 C618. Move |\input| from the stomach to the mouth. @378 C619\>X260. Introduce |\chardef|, analogous to |\mathchardef|. @1038,1224 G620. Change |\unbox| to |\unhbox| and |\unvbox|; also add |\unhcopy|. @1110 C621. Consider |\spacefactor|, |\pagetotal|, etc., as part of \\{prefixed_command}, even though they are always global. @1211 * 20 Jan 1983 C622. Switch modes when |\hrule| occurs in horizontal mode or |\vrule| in vertical. @1090,1094 G623. Add a new |\globaldefs| feature. @1211 * 21 Jan 1983 E624. Optimize the code, in places where it's important (based on frequency counts of \TeX\ usage accumulated during the past week): Introduce \\{fast_get_avail} and \\{fast_store_new_token}; reduce procedure-call overhead in \\{begin_token_list}, \\{end_token_list}, \\{back_input}, \\{flush_node_list}; change some tests from `{\bf if} $a\land b$' to `{\bf if}~$a$ {\bf then if}~$b$'. @122,371 * 22 Jan 1983 E625. Save space in math lists: Don't insert penalties within restricted horizontal mode; simplify trivial boxes. @721,1196 S626. Fix a surprising oversight in the \\{rebox} routine: Ensure that $b$ isn't a vbox. @715 C627\>545. Make |\nullfont| a primitive, so that \\{cur_font} always has a value. (This is a dramatic improvement over \TeX78, where a missing font was a fatal error called `|Whoa|'!) @552 * 24 Jan 1983 I628\>586. List all incomplete |\if|'s when the job ends. @1335 * 29 Jan 1983 C629\>552. Change initialization of \\{align_state} so that |\halign\bgroup| works. @777 * 30 Jan 1983 D630\>625. Be sure to test `\\{is_char_node}($q$)' when checking for a trivial box. @721 # By extraordinary coincidence, this bug was caught when somebody used font number~11 ($=\\{kern_node}$) in the second character of a list of length~2! I631\>X168. Improve format for stats at end of run, as suggested by DRF. @1334 # The changes above have been incorporated into Version 0.95. C632. Don't ignore the space after a control symbol (except `|\ |'). @354 P633. Remove all trailing spaces at the right of input lines, so that there's perfect compatibility with IBM systems that extend short lines with spaces. @31 * 3 Feb 1983 I634. Assume that a \\{math_accent} was intended, after giving an error message in the case $\\{mmode}+\\{accent}$. @1165 G635. Add new primitives |\iftrue| and |\iffalse|. @488 * 6 Feb 1983 A636\>X304. Improve the accuracy of fixed-point arithmetic when calculating sizes for |\left| and |\right|. (I had started by dividing \\{delimiter_factor}, not \\{delta1}, by 500.) @762 * 12 Feb 1983 C637. Change the name |\delimiterlimit| to |\delimitershortfall|. @248 C638. Make |\abovewithdelims..| equivalent to |\above|; change the order of operands so that delimiters precede the dimension. @1182 C639\>607. Remove the kludgy math codes introduced earlier; make |\fam| a normal integer parameter and allow |\mathcode| to equal $2^{15}$. @1233 R640. Don't let |\spacefactor| become more than $2^{15}$. @1233,1243 # I finished drafting Chapter 17 today. * 14 Feb 1983 I641\>639. Replace octal output (\\{print_octal}) by hexadecimal (\\{print_hex}) so that math codes are clearer. @67 F642\>619. Don't forget \\{char_given} in the \\{math_accent} routine. @1124 * 17 Feb 1983 C643\>622. Switch modes when |\halign| occurs in horizontal mode, or |\valign| in vertical mode. @1090,1094 * 18 Feb 1983 I644. Add a new feature |\tracingrestores|. This requires a new procedure called \\{show_eqtb}, whose code can be interspersed with the \\{eqtb} definitions. @252 * 25 Feb 1983 I645\>622. Suggest using |\leaders| when the user tries a horizontal rule in restricted horizontal mode. @1095 * 27 Feb 1983 I646. Specify the range of source lines, when giving warning messages for underfull or overfull boxes in alignments. @662,675 # Why did it take me all day to type the middle part of Chapter 18? * 4 Mar 1983 G647. Introduce a new feature |\xcr| (suggested by LL). [Changed later to `|\crcr|'.] @785 I648\>631. Subtract out \TeX's own string requirements from the stats. @1334 * 6 Mar 1983 G649. Add new features |\everyhbox| and |\everyvbox|. @1083,1167 * 9 Mar 1983 R650\>X295. Avoid accessing \\{math_quad} when the symbol fonts aren't known to be present. @1199 P651\>533. Introduce \\{float} and \\{unfloat} macros to aid portability (HWT). @109 C652. Introduce new names |\abovedisplayskip| and |\belowdisplayskip| for the old |\dispskip|; also |\abovedisplayshortskip| and |\belowdisplayshortskip| for the old |\dispaskip| and |\dispbskip|. @226 * 10 Mar 1983 C653. Unbundle |\romannumeral| from |\number| (suggested by FY). @468 * 12 Mar 1983 C654. Ignore leading spaces in \\{scan_keyword}. @407 * 14 Mar 1983 E655\>631. Use \\{write} and \\{write_ln} directly when printing stats. @1334 * 16 Mar 1983 Q656\>602. Refine the page-break cost function (introducing `\\{deplorable}', which is not quite `\\{awful_bad}'), after suggestion by LL. @974,1005 # The changes above have been incorporated into Version 0.96. * 18 Mar 1983 G657. Add a new feature |\everyjob| suggested by FY. @1030 * 19 Mar 1983 I658. Don't treat left braces specially when showing macros. @294 C659. Ignore blanks that would otherwise become undelimited arguments. @393 * 21 Mar 1983 F660\>X280. Make |\lastskip| handle \\{mu_glue} as well as ordinary glue. @424 C661\>561. Expand only one level in a preamble |\span|. @782 * 22 Mar 1983 C662. Let a single |#| suffice in |\tokens|, |\message|, etc. (The previous rule, in which |##| was always required as in macros, was a loser especially in |\write| where you had to say |####|!) @477 C663\>X328. Require the keyword `|to|' in |\read|. (This will avoid the common error of an incomplete constant when no space appears before the |\cs|.) Also allow terminal I/O as a default when a stream number is out of range. @482,1225,1370 * 26 Mar 1983 C664. Replace |\ifeven|\ by |\ifodd|\, for better consistency of language. @504 S665\>564. Introduce the \\{change_if_limit}, to overcome a big surprise bug relating to |\if\if aabc\fi|. @497 # Such examples show that \\{cur_if} might not be current, in my original implementation. * 28 Mar 1983 G666\>X326. Tolerate non-characters as arguments to |\if| and |\ifcat|. @506 C667. Change `|absent|' to `|void|', a better word. @487 C668. Clear the \\{shift_amount} in |\lastbox|, since I don't want to figure out what it means in all cases. @1081 * 29 Mar 1983 I669. Wake up the terminal before giving an error message. (This means a special \\{print_err} procedure is introduced.) (Suggested by DRF.) @34,73 * 1 Apr 1983 # Today I finished Chapter 21 (boxes) and began to draft Chapter 22 (alignments). G670. Allow periodic preambles in alignments. @793 C671. Make |\leaders| line up according to the smallest enclosing box. @627,636 Q672. Allow hyphenation after whatsits (e.g., after items for an index). @896 * 2 Apr 1983 Q673. Call \\{build_page} when |\par| occurs in vertical mode. @1094 C674. Clear \\{aux} in \\{init_row}, for tidyness. @786 * 4 Apr 1983 C675. Let digits switch families in math mode. @232 * 7 Apr 1983 Q676\>602. Refine the test for not splitting an insertion. @1008 * 8 Apr 1983 C677\>647. Rename |\xcr| as |\crcr|, at LL's request. @780 * 9 Apr 1983 # Took a day off and had a chance to help print a sample page on a 150-year-old letterpress in Murphys, California. * 11 Apr 1983 I678. Recover more sensibly after a runaway preamble. @339 * 12 Apr 1983 C679\>X328. Make |\read| span several input lines, if necessary to get balanced braces. @482 * 14 Apr 1983 S680. Fix a subtle bug found by JS: \S882 can make $q$ a \\{char_node}, so we need to test `{\bf if} $\lnot\\{is_char_node}(q)$'. [Actually I discovered much later that the real bug was to omit `{\bf else}' at this point.] @881 * 15 Apr 1983 C681. Make |\uppercase| and |\lowercase| apply to all characters, regardless of category. @1289 # 7:30am. After working all night, I completed a draft of the manual thru Chapter 22, for distribution to volunteer readers. # 5pm. The changes above have been incorporated into Version 0.97. * 17 Apr 1983 R682. Change `\\{small_number}' to `$0\,.\,.\,65$' in the hyphenation routine (DRF). @901 I683. Flush patterns in the input when the user tries |\patterns| outside of\/ |INITEX| (suggested by DRF). @1252 # Tomorrow I fly to England, where I'll lecture and write a paper about `Literate Programming' [{\sl Comp.~J. \bf27} (1984), 97--111]. * 14 May 1983 I684\>663. Improve the behavior of\/ |\read| from terminal (suggested by Todd Allen at Yale). [I'd forgotten to implement the extended stream numbers in \#663. Also, the prompt is now omitted if $n<0$.] @484 * 18 May 1983 I685. Restrict |\write| $n$ to the transcript file only, if $n<0$. @1350 C686\>X188. Unify the syntax for registers and internal quantities. (Remove primitives called `|\insthe|' and `|\minusthe|'; rename \\{scan_the} to \\{scan_something_internal}, and change its interface accordingly; clean up command codes generally.) @209,413 G687. Introduce new parameters |\hoffset|, |\voffset|. @617 * 24 May 1983 G688. Introduce a new parameter |\everycr| (suggested by MDS). @774,799 # Many macro writers and preliminary-manual readers have been requesting new features; I'll try to keep the language as concise and consistent as possible. * 25 May 1983 G689. Introduce |\countdef|, |\dimendef|, etc.\ (suggested by DRF long ago, easy now in view of \#686). @1224 G690. Introduce |\advance|, |\multiply|, |\divide| (suggested by FY). @1240 G691. Introduce |\hyphenchar|; this requires a new command \\{assign_font_int}, plus minor changes to about 15 modules. @915 G692. Introduce |\skewchar| (easy because of \#691). @741 G693. Introduce |\noexpand|. (I had difficulty thinking of how to implement this one!) @358,369 G694. Introduce |\meaning|. @296 G695\>X231. Remove `|dm|' and `|vu|'; allow the more general `|.5\hsize|'. @455 C696. Change `|\texinfo| $f$ $n$' to `|\fontdimen| $n$ $f$'. @578 * 27 May 1983 G697. Add a new feature |\afterassignment| (suggested by ARK). @1269 C698\>619. Adjust the timing so that commands like `|\chardef\xx=5\xx|' behave sensibly. @1224 * 28 May 1983 C699. Ignore `|\relax|' as if it were a space, in math mode and in a few other places where |\relax| would otherwise be erroneous. @404 Q700. Improve |\mathaccent| spacing with respect to subscripts and superscripts (suggested by HWT). @742 * 30 May 1983 C701\>598. Terminate a job only when $\\{dead_cycles}=0$. @1054 # The changes above constitute Version 0.98. * 3 Jun 1983 # I finished the draft of Chapter 23 (output routines) today. G702. Allow |\mark| and |\insert| and |\vadjust| in restricted horizontal mode, and also in math mode. (This is a comparatively big change, triggered by the fact that |\mark| in a display presently causes \TeX\ to crash with `|This can't happen|'!) The global variable \\{adjust_tail} is introduced. @796,888,1085 * 6 Jun 1983 G703\>695. Replace (and generalize) the previous uses of\/ |ht|, |wd|, and |dp| in dimensions by introducing the new control sequences |\ht|, |\wd|, and |\dp|. @1247 I704. Display sub-parts of noads with the symbols |^| and |_| instead of |(| and~|[|. @696 C705\>694. Allow |A..F| in hex constants to be \\{other_char} as well as \\{letter}. @445 * 7 Jun 1983 E706\>654. Remove an instance of \, since it's now redundant. @457 C707. Legalize |\mkern\thinmuskip| and |\mkern5\thinmuskip|. @456 C708. Clean up the treatment of optional spaces in numerical specifications. @455 # A construction like |2.5\space\space\dimen0| was previously valid after `|plus|' or `|minus|' only! # I'm obviously working on Chapter~24 today. C709\>545. Allow `|\font|' as a \ for the current font. @577 C710\>623. Don't make |\gdef| global when $\\{global_defs}<0$. @1218 E711. Produce \\{zero_glue} as the outcome of |\advance\spaceskip by-\spaceskip|. @1229 I712. Make |\show| do something appropriate for every possible token. @1294 G713\>559. Replace the (single) |\tokens| parameter by an array of 256 token registers. @230 C714. Allow |\indent| in math mode; also make |\valign| in math mode produce the `|Missing|~|$|' error. @1046,1093 E715. Remove redundant code: There's no need to check \\{cur_group} or call \\{off_save} when starting alignments or equation numbers in displays. @1130,1142 * 8 Jun 1983 C716. Disallow |\openout-1| and |\closeout-1|. @1350 C717. Disallow |\lastbox| in math mode. @1080 * 9 Jun 1983 I718. Call \\{back_error}, not \\{error}, when |\leaders| aren't followed by proper glue. @1078 D719. Initialize for a possible paragraph, after |\noalign| in a |\valign|. @785 * 10 Jun 1983 C720\>708. Expand the optional space after an ASCII constant. @442 * 12 Jun 1983 C721. Set $\\{space_factor}\gets1000$ after a rule or a constructed accent. @1056,1123 * 14 Jun 1983 D722. Correct a serious blunder: Set $\\{disc_width}\gets0$ before testing if $s$ is null (caught by JS). @869 # This is a real bug that existed since the beginning! It showed up on page~37 of the Version~0 |TRIP| manual, but I didn't notice the problem. C723\>708. Make optional spaces after \ like those after \. @448 C724\>568. Insert \\{every_display} before calling \\{build_page}. @1145 I725\>648. Report \TeX's capacity on overflow errors in a way that's fully consistent with other statistical reports. @42 * 17 Jun 1983 C726. Make all |\tracing| decisions on the basis of $\ge$ versus $<$, not $\ne$ versus~$=$. @581 # Today I finished the draft of Chapter 27 (the last chapter)! # The changes above were released as Version 0.99 on June 19, 1983. * 20 Jun 1983 C727. Set |\catcode`\%=14| in |INITEX|. @232 C728\>587. Call \\{normal_paragraph} when |\par| occurs in vertical mode. @1094 # Once again I'm retiring about 8am and awaking about 4pm. * 21 Jun 1983 C729\>558. Don't append an overfull rule solely because of\/ |\hbadness|. @666 R730. Don't allow the glue-ratio of shrinking to be less than~$-1$. @810,811 * 22 Jun 1983 B731\>653. Declare the parameter to \\{print_roman_int} to be of type \\{integer}, instead of \\{nonnegative_integer} (found by Debby Clark). @69 C732\>690. Make the keyword `|by|' optional (suggested by LL). @1236 * 24 Jun 1983 I733. Say `|preloaded|' when announcing \\{format_ident}. @1328 * 25 Jun 1983 R734. Add extra boxes and glue to the output of alignment. [This thwarts possible attempts at trickery by which system-dependent glue set values computed by |\span| could have gotten into \TeX's registers by things like |\valign| and |\vsplit|. It also has the advantage of perfect accuracy in alignment of vertical rules.] @809 C735. Make leaders affect the height or width of the enclosing boxes. @656,671 # Today I'm mainly installing a much-improved format for change files in |WEB| programs (suggested by DRF). * 28 Jun 1983 C736. Permit |\unskip| in vertical mode when we know that it does nothing. @1106 * 1 Jul 1983 E737\>700. Avoid redundant boxes when things like `|{\bf A}|' occur in math. @1186 G738. Add a `|scaled|' feature to |\font| input. @1258 D739\>700. Remember to correct \\{delta} when an accented box changes. @742 * 2 Jul 1983 R740.Introduce \\{bypass_eoln}, to remove anomalous behavior on input files of length~1. (Suggested by DRF after the problem was discovered by LL). @31 * 4 Jul 1983 G741. Allow codes like |^^b| as well as |^^B|. @352,355 G742. Introduce new parameters |\escapechar|, |\endlinechar|, |\defaulthyphenchar|, and |\defaultskewchar|, to make \TeX\ less dependent on the character set. (This affects many modules, since a lot of error messages must be broken up so that they use \\{print_esc}.) * 7 Jul 1983 P743. Use a system-dependent function \\{erstat} when opening or closing files (suggested by DRF). @27 * 11 Jul 1983 # The computer is back up after more than 50 hours down time (due to air conditioning failure). I744. Show total glue in the output of\/ |\tracingpages|. @985 R745. Guard against insertion into an hbox. @993 C746. Legalize the assignment \=\. @1227 I747. Introduce a new parameter |\errhelp|. @1283 F748\>623. Don't forget to check \\{global_defs} when |\tabskip| is changed. @782 * 12 Jul 1983 C749. Allow an |\outer| macro to appear after |\string|, |\noexpand|, and |\meaning| (Todd Allen). @369,471 C750. Make `|\the|' an expandable control sequence (i.e., move it from the stomach to the throat); this cleans up several annoying glitches. @367 C751\>620. Allow |\unhbox| and |\unhcopy| in math mode if the box is void. @1110 * 13 Jul 1983 # I lectured for four hours at the TUG meeting today after very little sleep! * 16 Jul 1983 # The following were suggested by TUG meeting discussions. L752. Round the value of \\{default_rule} more properly: It should be 26215. @463 Q753\>700. Fix |\mathaccent| again; it's still not right! The final height should be the maximum of the height of accented letter without superscript and the height of unaccented letter with superscript. @742 G754. Add a new feature |\newlinechar|. @59 G755. Allow boxes and rules in discretionaries (suggested by somebody from Hewlett-Packard). @1121 I756\>X28. Show all token expansions, not just macros, when |\tracingcommands|. @367 C757. Allow |\char| in a |\hyphenation| list. @935 G758. Introduce a new feature |\aftergroup|; it can be implemented with \\{save_stack}. @326 C759. Run the running dimensions to alignment boundaries (suggested by ARK). @806 * 17 Jul 1983 R760. Zero out \\{hyf} values at the edges, so that weird pattern data cannot lead to Pascal range checks. @965 R761\>X190. Decrease the |hc| codes for hyphenation, so that code~127 cannot possibly be matched. @937,962 C762\>672. Allow whatsits after hyphenatable words. @899 C763\>604. Represent an italic correction as an explicit kern. @1113 * 18 Jul 1983 C764. Allow lowercase letters in file names. @519 I765. Change the message `|No output file|' to: `|No pages of output|'. @642 I766. Confirm that a quiet mode is being entered, when error interaction ends with |Q|, |R|, or |S| (suggested by ARK). @86 # Version 0.999 was finally installed today; a new program listing has been printed. # From now on, I plan to keep all section numbers unchanged. # I'm done writing Appendix~H; beginning to revise Chapter~20. * 25 Jul 1983 C767\>663. Allow space after `|to|' in the |\read| command (FY). @1215 # To bed at 1pm today. * 27 Jul 1983 S768\>665. Stack the current type of\/ |\if|; this precaution is necessary in general (FY). @498 # To bed at 2pm today. * 29 Jul 1983 E769. Avoid putting a control sequence in the hash table when it occurs after |\ifx|. (Requested by Math Reviews people.) @507 # Finished a version of {\sl The \TeX book\/} lacking only Appendices D, E, and~I, for distribution to interested readers. # To bed at 10:30pm, planning to arise regularly at 6am for a change. * 31 Jul 1983 I770\>766. Call \\{update_terminal} when going quiet (HWT). @86 * 1 Aug 1983 C771. Don't put an empty line at the end of an |\input| file! (This simplifies the rules and the program, and also gets around a bug that occurred at the end of files with $\\{end_line_char}<0$.) @362 # The changes above went into Version 0.9999, which was widely distributed. * 16 Aug 1983 B772\>665. Rectify a ridiculous gaffe: I initialized $q$ every time the loop of \\{change_if_limit} was performed! (Found by FY.) @497 I773\>648. Distinguish `|string|' from `|strings|' when reporting statistics. @1334 A774. Introduce \\{lx}, to correct a bug in |\xleader| computations (found by FY). @627 * 20 Aug 1983 F775. Don't forget to apply |\/| to ligatures. @1113 # Today I began to read all previous issues of {\sl TUGboat}, in preparation for Appendix~D. * 27 Aug 1983 I776. Add debugging hack number~16, to help catch subtle data structure bugs. @1339 E777. Remove redundant setting and resetting of \\{name_in_progress}. @531 S778\>618. Suppress |\input| during a font size spec; otherwise \\{cur_name} is clobbered (found by MDS). @1258 G779. Introduce new conditionals |\ifhbox| and |\ifvbox|. @505 * 29 Aug 1983 D780\>750. Test for an empty list, if emptiness will mess up the data structure. (Found by Todd Allen.) @478 E781\>624. Use \\{fast_store_new_token} in another place for efficiency. @466 I782. Say `|has only|' instead of `|has|'. @579 # These changes yield Version 0.99999, used only at Stanford. * 30 Aug 1983 C783. Make funny blank spaces showable. @298 * 31 Aug 1983 C784\>754. Make |\newlinechar| affect \\{print_char}, not just \\{print}. @58 * 4 Sep 1983 G785. Add new features |\lastkern|, |\lastpenalty|, |\unkern|, |\unpenalty|. @424,996,1105 # OK, Appendix D is finished!! # The above changes have been installed in Version 0.999999. * 17 Sep 1983 P786\>548. Don't bother making duplicate font identifiers; that was overkill, not really needed. @1258 # Will this be the historic last change to \TeX? * 18 Sep 1983 I787. Correct a minor inconsistency, `|display|' not `|displayed|'. @211 * 20 Sep 1983 C788\>604. Treat the kerns inserted for accents as explicit kerns. @1125 * 26 Sep 1983 I789. Change `|log|' to `|transcript|' in several messages. @535,1335 # The index was finished today; I mailed the entire {\sl \TeX book\/} to Massachusetts for final proofreading before publication. * 1 Oct 1983 D790. Prevent uninitialized trie positions in case of overflow (found by Bernd Schulze). @944 * 7 Oct 1983 # Henceforth our weekly `\TeX\ lunch' meetings will be called `\MF\ lunch'. # DRF begins to produce {\sl The \TeX book\/} on our APS phototypesetter. * 14 Oct 1983 P791\>633. Ignore spaces at the ends of lines also in |TEX.POOL| (found by DRF). @52 D792\>610. Initialize the \\{history} variable at \\{start_here} (DRF). @1332 * 18 Oct 1983 I793. Extend \\{runaway} to catch runaway text (suggested by FY). @306 D794. Reset \\{cur_cs} after \\{back_input}, not after scanning the `|=|' (found by FY). @1226 * 24 Oct 1983 I795\>638. Change the error recovery for bad delimiters, in accordance with the changed syntax. (Found by Barry Smith.) @1183 * 9 Nov 1983 E796. Optimize the code a bit more, based on empirical frequency data gathered during September and October: In \S45, use the fact that the result is almost always true. In \S380, delete `{\bf while} \\{true} {\bf do}' since many compilers implement that badly. Rewrite \S852 to avoid calling \\{badness} in the most common case. @45,380,852 * 3 Dec 1983 F797. Don't forget to call |error| after the message has been given (noticed by Gabi Kuper). @500 # Version 1.0 released today incorporates all of the above. * 9 Dec 1983 # Dinner party with 36 guests to celebrate \TeX's coming of age. * 2 Feb 1984 S798\>786. Reinstall |\font| precautions that I thought were unnecessary. I overlooked many problematic possibilities, like `|{\font\a=x| |\global\a}| |\the\font|' and `|\font\a=x| |\font\b=x| |\let\b=\undefined| |\the\a|', etc. (Found by Mike Urban.) The new remedy involves removal of the \\{font_ident} array and putting the identifiers into a frozen part of the hash table; so there's a sprinkling of corrections in lots of modules. But basically the change is quite conservative, so it shouldn't spawn any new bugs (it says here). @222,267,1257 * 9 Feb 1984 S799. Remove the possibility of double interrupt, in a scenario found by Clint Cuzzo. @1031 * 12 Feb 1984 Q800. Improve spacing in a formula like |$(A,<)$|. @764 * 13 Feb 1984 A801. Avoid a bad {\bf goto}, as diagnosed by Clint Cuzzo and George O'Connor. (Must not go directly to \\{switch}.) @346 E802. Conserve string pool space by not storing file name in two guises (suggested by DRF). @537 * 26 Feb 1984 I803. Make scaled output look cleaner by printing fewer decimals whenever this involves no loss of accuracy. (Suggested by \MF\ development.) @103 * 2 Mar 1984 R804. Maintain 17-digit accuracy, not 16; now constants like `|.00000762939453126pt|' will round correctly. @452 * 16 Mar 1984 R805. Plug a loophole that permitted recursion in \\{get_next}, by disallowing deletions in \\{check_outer_validity}. @336 * 24 Mar 1984 I806. Open the terminal before trying to wake it up, when the program starts bad. @1332 * 27 Mar 1984 R807. Check that $k<63$, to avoid the |\patterns{xxx...xxxdxxxdxxx}| anomaly found by Jacques D\'esarm\'enien. @962 * 11 Apr 1984 F808. Supply code for the missing case \\{adjust_node} in \\{copy_node_list}. @206 # Yoicks, how could serious bugs like that have escaped detection? * 11 Jun 1984 D809\>627. Initialize \\{char_base}, etc., for \\{null_font}. (Found by Nick Briggs.) @552 R810. Clear the \\{buffer} array initially (Briggs). @331 * 21 Jun 1984 C811. Look ahead for ligature or kern after a |\chardef|'d item (D\'esarm\'enien). @1038 * 4 Jul 1984 R812. Make the quarterword constraint explicit with a new `\\{bad}' case (19). @111 * 7 Jul 1984 E813. Optimize \\{firm_up_the_line} slightly, to be consistent with the \MF\ program. @363 * 8 Jul 1984 I814. Give additional diagnostics when |\tracingmacros>1|. @323 # The changes above were incorporated in Version 1.1, released July 9, 1984. * 27 Jul 1984 I815. Say `|see| |the| |transcript| |file|' after handling offline |\show| commands. (Suggested by \MF.) @1298 * 20 Oct 1984 I816. Allow `|0|' in response to error prompts. @84 # Those two changes led to Version 1.2. * 25 Nov 1984 R817. Don't forget to check for \\{null} before looking at subfields of a node. (This was ``dirty Pascal,'' with two quarterword 0's read as a halfword.) @846 R818. Ditto in another place! @939 E819. Remove the fixed-at-compile-time partition between lower and upper memory. @116,125,162 # This major change in memory management completes Version 1.3, which was published in preliminary looseleaf form as `\TeX: The Program'. * 20 Dec 1984 R820. Keep the \\{node_size} field from overflowing if the lower part of memory is too large. @125 # That was another bug in existence from the beginning! * 5 Jan 1985 I821. Improve the missing-format-file error (DRF). @524 * 7 Jan 1985 I822. Update the terminal right away so that the welcoming message will appear as soon as possible (DRF). @61 * 23 Jan 1985 I823. Convey more uncertainty in the help message at times of \\{confusion}. @95 I824\>610. Improve the \\{history} logic in the \\{warning_issued} case. @245 * 18 Feb 1985 P825\>810. Stick to standard Pascal: Don't use \\{first} in a {\bf for} loop. [Some procedures ``threaten'' it globally, according to British Standard 6192, section 6.8.3.9.] (Pointed out by CET.) @331 * 11 Apr 1985 S826. Prevent nonexistent characters from being output by unusual combinations of ligatures and hyphenation. @915 * 15 Apr 1985 L827\>819. Compute memory usage correctly in |INITEX|; the previous number was wrong because of a |WEB| text macro without parentheses (DRF). @164 * 16 Apr 1985 E828. Speed up \\{flush_list} by not calling \\{free_avail} (DRF). @123 * 17 Apr 1985 A829\>788. Introduce a special kind of kern for accent positioning; it must not disappear after a line break. @837,879,1125 * 18 Apr 1985 R830\>755. Prevent |\lastbox| and |\unkern| from removing discretionary replacements. @1081,1105 # That completes Version 1.4. * 26 Apr 1985 C831. Don't try \\{\TeX_area} if a nonstandard file area has been specified (DRF). @537 # That was \#401 in \TeX78; I never learn! * 30 Apr 1985 C832\>754. Eliminate the limitation on |\write| length; the reason for it has disappeared (Nancy Tuma). @1370 * 8 May 1985 D833\>819. Allocate two words for the head of the \\{active} list (CET). @162 * 11 May 1985 I834. Change \\{wterm} to \\{wterm_ln} after a bad beginning (Bill Gropp). @1332 E835\>806. Don't open the terminal twice (CET). @1332 * 22 May 1985 R836. Test for \\{batch_mode} after trying to open the transcript file, not before (DRF). @92 R837. Be prepared for string pool overflow while reading the command line! (This bug was first found in \MF, when it could occur more easily.) @525 * 7 Aug 1985 A838. Fix a bug in |\edef\foo{\iffalse\fi\the\toks0}|: \TeX\ should stay in the loop when expanding non-|\the|. (Found by Dan Brotsky.) @478 # The above changes were incorporated in Version 1.5. * 27 Nov 1985 C839\>764. Make `|plain|' a lowercase name, for consistency with the manual. @521 I840\>669. Wake up the terminal for |\show| commands. @1294,1297 # The above changes were incorporated in Version 2.0, which was published as Volume~B of the {\sl Computers \& Typesetting\/} series. * 15 Dec 1986 I841. Punctuate the Poirot help message more carefully. @1283 * 28 Jan 1987 R842. Make sure that \\{max_in_open} doesn't exceed 127 (DRF). @14 D843\>680. Don't allow a |\kern| to be clobbered at the end of a pre-break list when a discretionary break is taken. (A missing `{\bf else}' was the source of the error, diagnosed incorrectly before.) @881 D844. Take account of discarded nodes when computing the background width after a discretionary. @840 # That was the first really serious bug detected for more than 17 months! I found it while experimenting with right-to-left extensions. # Version 2.1 was released on January 26, 1987. * 5 Feb 1987 E845. Remove cases in \\{shorthand_def} that cannot occur (found by Pat Monardo). @1224 * 14 Apr 1987 R846. Improve robustness of data structure display when debugging (Ronaldo Am\'a). @174,182 * 21 Apr 1987 E847. Make the storage allocation algorithm more elegant and efficient. @127 * 22 Apr 1987 A848\>742. Calculate the empty-line condition properly when \\{end_line_char} is absent. @360 # The previous three changes were found while I was teaching a class based on Volume~B; they led to Version 2.2. * 28 Apr 1987 E849. Avoid closing a file when \TeX\ knows that it isn't open (JS). @560 * 3 Aug 1987 S850. Clean up unfinished output if it's necessary to \\{jump_out} (Klaus Gunterman). @642 # That makes Version 2.3; subsequent version numbers won't be logged here. * 19 Aug 1987 A851. Indent rules properly in cases like\hfil\break |\hangindent=1pt$$\halign{...\cr\noalign{\hrule}}$$|. @806 * 20 Aug 1987 S852. Introduce \\{co_backup} because of cases like |\hskip 0pt plus 1fil\ifdim| (Alan Guth). @366 * 9 Nov 1987 S853. Change the calculation for number of leader boxes, so that it won't be too sensitive to roundoff error near exact multiples (M. F. Bridgland). @626 * 17 Nov 1987 A854. Replace my stupid algorithm for fixed-point multiplication of negatives (WGS). @572 * 12 Dec 1987 B855. Fix a typo in the initialization of hyphenation tables (PB). @952 # That error was almost completely harmless, thus undetectable, except if some |\lccode| is~1 and no |\patterns| are given. * 23 Dec 1987 S856\>564. Be more cautious when ``relaxing'' a previously undefined |\csname|; you might be inside a group (CET). @372 * 20 Apr 1988 S857. Make sure \\{temp_head} is well-formed whenever it can be printed in a ``runaway'' message: Consider constructions like |\outer\def\a0{}\a\a| (Silvio Levy). @391 * 24 Apr 1988 S858\>618. Avoid conflicting use of the string pool in constructions like |\def\\#1{}\input a\\\z| (Robert Messer). @260 * 10 May 1988 R859. Amend the |\patterns| data structure when $\\{trie_min}=0$ (PB). @951,953 * 25 May 1988 R860. Guarantee that \\{trie_pointer} cannot be out of range. @923 S861\>618. Avoid additional bugs like \#858 in constructions like |\input a\romannumeral1|, etc. @464,465,470 R862\>618. Prevent similar string pool confusion that could occur during the processing of |**\input\romannumeral6|. @525 * 19 Jun 1988 S863\>819. Prevent a negative dividend from rounding upward, causing a loop (CET). @126 E864\>819. Adopt a smoother allocation strategy when memory is nearly gone (CET). @126 * 20 Jun 1988 D865\>852. Initialize \\{cur_order}, now that it's being backed up (Tsunetoshi Hayashi). @439 * 6 Nov 1988 S866\>612. Disable \\{fatal_error} in \\{prompt_input}, so that \\{open_log_file} can use it safely (Tim Morgan). @71 S867\>836. Force terminal output whenever \\{open_log_file} fails. @535 * 14 Dec 1988 P868\>866. Restore \\{fatal_error} in \\{prompt_input}, but don't let it be unsafe for \\{open_log_file}. @92,534 * 23 Jan 1989 D869. Give $q$ a legal value when recovering from ``infinite shrinkage'' error. @976,1004 * 17 Feb 1989 D870\>758. Avoid spurious error message for |\aftergroup\relax\dump| by avoiding inaccessible |\aftergroup| tokens (FM and Rainer Sch\"opf). @280 * 20 Mar 1989 R871. Don't refer to \\{link}(\\{null}) even when it ``can't happen'' (PB). @791 * 7 Jun 1989 S872. Avoid confusion from |$$\begingroup\halign{#\cr}$$| (FM). @1130 * 20 Jun 1989 S873. Put fraction digits into dynamic memory, not the global \\{dig} array, because of constructions like |.5\ifdim.6| (FM). @452 * 17 Jul 1989 S874. Prevent embarrassing attempts to report errors before the string mechanism has been fully initialized, for example when the command line exceeds the buffer size (WGS). @31 * 16 Aug 1989 M875. Allow integer products to be 31 bits long (FM). @105 * 31 Aug 1989 C876\>441. Increase the number of tokens shown by \\{token_show} (J. Lavagnino). @295 S877. Avoid confusion from |$$\begingroup\eqno$$| (FM). @1140 # The recent TUG meeting turned out to be an extend-\TeX-for-the-nineties party! I agreed that some extensions for non-English languages ought to be made while I still knew how to do them. (In other words, I broke my firm commitment to keeping \TeX\ completely stable; but in this case nobody objected.) The following eleven changes were coded during the month of September. * 30 Sep 1989 G878. Install major change allowing general 8-bit code input. @38,352 G879. Install major change allowing multiple hyphenation tables (M. Ferguson). @923 G880. Introduce new parameters |\lefthyphenmin| and |\righthyphenmin|. @923 G881. Introduce major new ligature capabilities including implicit boundary characters. @908,1037 G882. Install new |\inputlineno| feature suggested by MDS. @424 G883. Install new |\holdinginserts| feature suggested by FM. @1014 G884. Install new |\badness| feature. @424,664 G885. Install new |\emergencystretch| feature. @863 G886. Install new |\errorcontextlines| feature suggested by FM. @311 S887. Recover from anomaly when hyphenation |char_warning| clobbers |old_setting|. @863 P888. Make it easier to change the format extension (Don Hosek). @520,1328 * 16 Oct 1989 R889. Avoid range check in null font with |bc=256| (PB). @565 * 22 Nov 1989 S890\>856. Prevent \\{save_stack} conflicts in |{\hbox\expandafter{\csname\endcsname}}| and\kern-3pt\break similar constructions (WGS). @645,1117 S891\>858. System-dependent parts of file names must be addressed relatively, not absolutely (FM and Rainer Sch\"opf). @516,517 * 3 Dec 1989 G892\>880. Allow different hyphenmins in the same paragraph (M. Ferguson). @1376 S893. Distinguish |\par| from characters on |\if| tests. (MVL). @334 S894\>378. Alignments need to be more robust against malicious attacks (MVL). @782 C895. Don't let kerns in discretionaries disappear at breaks (MVL). @869 Q896\>881. Make the new hyphenation reconstruction procedure less cautious, so that it doesn't lose hyphens found by the old method. @914 * 11 Dec 1989 D897\>879. Make an undumped trie dumpable again (PB). @1325 * 18 Dec 1989 G898\>588. Allow access to page totals in |\output| routines (FM and Chris Rowley). @421 * 22 Jan 1990 R899\>611. Recognize more cases of unbalanced |\output| (CET). @1026 * 29 Jan 1990 S900\>758. Make |\aftergroup| work properly after |\eqno| (Michael Downes). @1194 * 1 Feb 1990 S901\>878. Fix one more case of \\{end_line_char_inactive} (WGS). @360 * 22 Feb 1990 R902. Don't lose the last active node when total demerits are very high (FM). @836,854 * 13 Mar 1990 D903. Doublecheck math fonts after making equation number (MVL). @1194 D904. Don't forget to rule out charnodes before testing \\{type} (MVL). @805,1202 * 23 Mar 1990 F905\>881. Don't change the font of punctuation preceding a hyphenated word (Scott C. Allendorf). @903 I906. Balance the parentheses shown on the terminal during normal runs. @1335 E907. Optimize |\ifx\p\q| after |\let\p=\q| (MVL). @508 S908. Treat migration properly in displays (MVL). @1199,1205 # We're now up to Version 3.0; I sincerely hope all bugs have been found. * 11 May 1990 F909\>881. Initialize |\nullfont| ligature parameters (Lance Carnes). @552 * 22 July 1990 S910\>579. Treat |\prevgraf| as zero within |\write| (Bogus\l aw Jackowski). @422 * 26 July 1990 S911. Report `|l.1|' when first line of file overflows buffer (George Russell). @538 * 5 December 1990 S912\>878. Translate unprintable characters in font identifiers (WGS). @63 * 28 December 1990 R913. Avoid range check when there are 65536 or more pages (Eberhard Mattes). @642 * 20 September 1991 I914\>878. Improve error message for |\mathchar| out of range. @436 S915\>878. Retain unprintable internal strings in 8-bit form (FM). @59 S916\>881. Retain right punctuation context for ligature reconstruction (problem found by Brian Hamilton Kelly). @903 * 10 January 1992 S917\>881. Also avoid producing a double kern at boundary (CET). @897 S918. Disallow |\setbox| where it doesn't work (Robert Hunt). @1241,1270 S919. Robustify |\mskip| and |\mkern| in presence of negative quad (WGS). @716,717 S920\>679. Defend against `|}{|' in |\read| (Michael Downes). @483 E921\>798. Save string memory if font occurs repeatedly (Bogus\l aw Jackowski). @1260 S922\>784. Don't let |\newlinechar| interrupt unprintable expansion (Bernd Raichle). @59,60 * 7 February 1992 D923\>881. Restore |cur_l| properly when boundary character doesn't exist (Mattes and Raichle). @1036 * 17 July 1992 C924\>892. Use current language at beginning of horizontal mode (Rainer Sch\"opf and CET). @1091,1200 * 17 December 1992 R925\>879. Avoid (harmless) range errors (Philip Taylor and CET). @934,960 * 25 February 1993 C926\>881. Protect kerns inserted by boundary characters (William Baxter). @837,866 S927\>917. Don't let boundary kern disappear after hyphenation. @897 * 26 June 1993 R928\>668. Avoid potential future bug (Peter Breitenlohner). @628,637 * 17 December 1993 S929\>881. Boundary character representation shouldn't depend on the font memory size (Berthold Horn). @549,1323 * 10 March 1994 R930. Huge font parameter number may exceed array bound (CET). @549 * 4 September 1994 F931\>926. Math kerns are explicit (Walter Carlip). @717 R932. Avoid overflow on huge real-to-integer conversion. @625,634 * 19 March 1995 R933. Avoid spurious reference counts in format files (PB). @1335 * 23 November 1998 R934. Make sure that TeX is certifiably Y2K-safe. @1328 * 12 July 1999 A935\>255. |\xleaders| often drops the final box (Hiroshi Nakashima). @627,636 * 30 August 2001 R936. Don't allow a million unbalanced braces followed by |\cr| outside of any alignment (Ralf Roth). @789 R937. Don't allow end-template except at end of template (Roth). @325,1131 * 30 September 2002 Q938. Improve rounding of glue during output (M. F. Bridgland). @625,634 * 18 March 2008 F939. Forgot to goto the proper error recovery (DRF). @395 E940. Avoid a case of dirty Pascal and speed up inner loop. @1035 R941. Forget reference to last_glue in format file (DRF). @1335 R942. Glue reference not updated after overflow error (DRF). @1236 B943. Muglue in \leaders had wrong units; now disallowed (DRF). @1078 E944. Speedup of ligatures and kerns at end of a word (DRF). @1039 R945. Another sanity check of TFM files for security (DRF). @365 I946. Give better size data for unmagnified insertions. @986 * 6 January 2014 C947. Space after \csname\endcsname to match other spaces. (Oleg Bulatov) @262 \relax \bye Up to a point it is better to let the snags [bugs] be there than to spend such time in design that there are none (how many decades would this course take?). -- A M Turing Proposals for Development in the Mathematics Division of an Automatic Computing Engine (ACE) Report E882, Executive Committee, National Physical Laboratory (NPL) 1945; reprinted in April 1972 as NPL report Com Sci 57 page 18 quoted by Carpenter and Doran in The Computer Journal 20 (1977), 273. DRF David Fuchs HWT Howard Trickey FY Frank Yellin LL Leslie Lamport JS Jim Sterken ARK Arthur Keller CET Chris Thompson FM Frank Mittelbach (added subsequent to publication of paper) PB Peter Breitenlohner (ditto) WGS Wayne G. Sullivan (ditto) MVL Marc van Leeuwen (ditto) MDS Michael D. Spivak (ditto)