%% This is part of the OpTeX project, see http://petr.olsak.net/optex \_codedecl \newif {Special if-macros, is-macros and loops <2022-12-02>} % preloaded in format \_doc ---------------------------- \secc Classical \code{\\newif} The \`\newif` macro implements boolean value. It works as in plain \TeX. It means that after `\newif\ifxxx` you can use `\xxxtrue` or `\xxxfalse` to set the boolean value and use `\ifxxx true\else false\fi` to test this value. The default value is false. The macro \`\_newifi` enables to declare `\_ifxxx` and to use `\_xxxtrue` and `\_xxxfalse`. This means that it is usable for the internal namespace (`_`prefixed macros). \_cod ---------------------------- \_def\_newif #1{\_ea\_newifA \_string #1\_relax#1} \_ea\_def \_ea\_newifA \_string\if #1\_relax#2{% \_sdef{#1true}{\_let#2=\_iftrue}% \_sdef{#1false}{\_let#2=\_iffalse}% \_let#2=\_iffalse } \_def\_newifi #1{\_ea\_newifiA \string#1\_relax#1} \_ea\_def \_ea\_newifiA \_string\_if #1\_relax#2{% \_sdef{_#1true}{\_let#2=\_iftrue}% \_sdef{_#1false}{\_let#2=\_iffalse}% \_let#2=\_iffalse } \_public \newif ; \_doc ---------------------------- \`\afterfi` `{}\fi` closes condition by `\fi` and processes . Usage: \begtt \catcode`<=13 \if \afterfi{} \else \afterfi{} \fi \endtt Nested `\if..\afterfi{\if..\afterfi{...}\fi}\fi` are possible. Another approach is mentioned in \ulink[http://petr.olsak.net/optex/optex-tricks.html\#fiinif]{OpTeX trick 0098} which also solves the `\fi` in `\if` problem. \_cod ---------------------------- \_long\_def \_afterfi#1#2\_fi{\_fi#1} \_long\_def \afterfi#1#2\fi{\_fi#1} \_doc ---------------------------- \secc Loops The \`\loop` ` \ifsomething ` \`\repeat` loops `` until `\ifsomething` is false. Then `` is not executed and loop is finished. This works like in plain \TeX, but implementation is somewhat better (you can use `\else` clause after the `\ifsomething`). There are public version `\loop...\repeat` and private version \`\_loop` ...\`\_repeat`. You cannot mix both versions in one loop. The `\loop` macro keeps its original plain TeX meaning. It is not expandable and nested `\loop`s are possible only in a \TeX/ group. \_cod ---------------------------- \_long\_def \_loop #1\_repeat{\_def\_body{#1}\_iterate} \_long\_def \loop #1\repeat{\_def\_body{#1}\_iterate} \_let \_repeat=\_fi % this makes \loop...\if...\repeat skippable \_let \repeat=\_fi \_def \_iterate {\_body \_ea \_iterate \_fi} \_doc ----------------------------- \`\foreach` ``\`\do` `{}` repeats `` for each element of the ``. The `` can include `#1` which is substituted by each element of the ``. The macro is expandable. \nl \`\foreach` ``\`\do` `{}` reads parameters from repeatedly and does for each such reading. The parameters are declared by . Examples: \begtt \foreach (a,1)(b,2)(c,3)\do (#1,#2){#1=#2 } \foreach word1,word2,word3,\do #1,{Word is #1.} \foreach A=word1 B=word2 \do #1=#2 {"#1 is set as #2".} \endtt Note that `\foreach \do {}` is equivalent to `\foreach \do #1{}`. Recommendation: it is better to use private variants of \`\_foreach`. When the user writes `\input tikz` then `\foreach` macro is redefined in each TikZ environment. The private variants use \`\_do` separator instead `\do` separator. \_cod ----------------------------- \_newcount\_frnum % the numeric variable used in \fornum \_def\_do{\_doundefined} % we need to ask \_ifx#1\_do ... \_long\_def\_foreach #1\_do #2#{\_isempty{#2}\_iftrue \_afterfi{\_foreachA{#1}{##1}}\_else\_afterfi{\_foreachA{#1}{#2}}\_fi} \_long\_def\_foreachA #1#2#3{\_putforstack \_immediateassignment \_long\_gdef\_fbody#2{\_testparam##1..\_iftrue #3\_ea\_fbody\_fi}% \_fbody #1#2\_finbody\_getforstack } \_def\_testparam#1#2#3\_iftrue{\_ifx###1\_empty\_ea\_finbody\_else} \_def\_finbody#1\_finbody{} \_long\_def\foreach #1\do#2#{\_isempty{#2}\_iftrue \_afterfi{\_foreachA{#1}{##1}}\_else\_afterfi{\_foreachA{#1}{#2}}\_fi} \_doc ----------------------------- \`\fornum` `..` \`\do` `{}` or \`\fornumstep` `: ..` \`\do` `{}` repeats `` for each number from `` to `` (with step `` or with step one). The `` can include `#1` which is substituted by current number. The , , parameters can be numeric expressions. The macro is expandable.\nl The test in the \`\_fornumB` says: if ( $\string<$ AND is positive) or if ( $>$ AND is negative) then close loop by `\_getforstack`. Sorry, the condition is writen by somewhat cryptoid \TeX/ language. \_cod ----------------------------- \_def\_fornum#1..#2\_do{\_fornumstep 1:#1..#2\_do} \_long\_def\_fornumstep#1:#2..#3\_do#4{\_putforstack \_immediateassigned{% \_gdef\_fbody##1{#4}% \_global\_frnum=\_numexpr#2\_relax }% \_ea\_fornumB\_ea{\_the\_numexpr#3\_ea}\_ea{\_the\_numexpr#1}% } \_def\_fornumB #1#2{\_ifnum#1\_ifnum#2>0<\_else>\_fi \_frnum \_getforstack \_else \_afterfi{\_ea\_fbody\_ea{\_the\_frnum}% \_immediateassignment\_global\_advance\_frnum by#2 \_fornumB{#1}{#2}}\_fi } \_def\fornum#1..#2\do{\_fornumstep 1:#1..#2\_do} \_def\fornumstep#1:#2..#3\do{\_fornumstep #1:#2..#3\_do} \_doc ---------------------------- The `\foreach` and `\fornum` macros can be nested and arbitrary combined. When they are nested then use `##1` for the variable of nested level, `####1` for the variable of second nested level etc. Example: \begtt \foreach ABC \do {\fornum 1..5 \do {letter:#1, number: ##1. }} \endtt Implementation note: we cannot use \TeX/-groups for nesting levels because we want to do the macros expandable. We must implement a special for-stack which saves the data needed by `\foreach` and `\fornum`. The \`\_putforstack` is used when `\for*` is initialized and \`\_getforstack` is used when the `\for*` macro ends. The \`\_forlevel` variable keeps the current nesting level. If it is zero, then we need not save nor restore any data. \_cod ---------------------------- \_newcount\_forlevel \_def\_putforstack{\_immediateassigned{% \_ifnum\_forlevel>0 \_sxdef{_frnum:\_the\_forlevel\_ea}{\_the\_frnum}% \_global\_slet{_fbody:\_the\_forlevel}{_fbody}% \_fi \_incr\_forlevel }} \_def\_getforstack{\_immediateassigned{% \_decr\_forlevel \_ifnum\_forlevel>0 \_global\_slet{_fbody}{_fbody:\_the\_forlevel}% \_global\_frnum=\_cs{_frnum:\_the\_forlevel}\_space \_fi }} \_ifx\_immediateassignment\_undefined % for compatibility with older LuaTeX \_let\_immediateassigned=\_useit \_let\_immediateassignment=\_empty \_fi \_doc ---------------------------- User can define own expandable \"foreach" macro by \`\foreachdef` `\macro {}` which can be used by `\macro {}`. The macro reads repeatedly parameters from using and does for each such reading. For example \begtt \foreachdef\mymacro #1,{[#1]} \mymacro{a,b,cd,efg,} \endtt expands to [a][b][cd][efg]. Such user defined macros are more effecive during processing than `\foreach` itself because they need not to operate with the for-stack. \_cod ---------------------------- \_def\_foreachdef#1#2#{\_toks0{#2}% \_long\_edef#1##1{\_ea\_noexpand\_csname _body:\_csstring#1\_endcsname ##1\_the\_toks0 \_noexpand\_finbody}% \_foreachdefA#1{#2}} \_long\_def\_foreachdefA#1#2#3{% \_long\_sdef{_body:\_csstring#1}#2{\_testparam##1..\_iftrue #3\_cs{_body:\_csstring#1\_ea}\_fi}} \_public \foreachdef ; \_doc ---------------------------- \secc Is-macros There are a collection of macros \^`\isempty`, \^`\istoksempty`, \^`\isequal`, \^`\ismacro`, \^`\isdefined`, \^`\isinlist`, \^`\isfile` and \^`\isfont` with common syntax: \begtt \catcode`\<=13 \issomething \iftrue \else \fi or \issomething \iffalse \else \fi \endtt The `\else` part is optional. The `` is processed if `\issomething` generates true condition. The `` is processed if `\issomething` generates false condition. The `\iftrue` or `\iffalse` is an integral part of this syntax because we need to keep skippable nested `\if` conditions. Implementation note: we read this `\iftrue` or `\iffalse` into unseparated parameter and repeat it because we need to remove an optional space before this command. \medskip\noindent \`\isempty` `{}\iftrue` is true if the `` is empty. This macro is expandable.\nl \`\istoksempty` `\iftrue` is true if the `` is empty. It is expandable. \_cod ---------------------------- \_long\_def \_isempty #1#2{\_if\_relax\_detokenize{#1}\_relax \_else \_ea\_unless \_fi#2} \_def \_istoksempty #1#2{\_ea\_isempty\_ea{\_the#1}#2} \_public \isempty \istoksempty ; \_doc ---------------------------- \`\isequal` `{}{}\iftrue` is true if the and are equal, only from strings point of view, category codes are ignored. The macro is expandable. \_cod ---------------------------- \_long\_def\_isequal#1#2#3{\_directlua{% if "\_luaescapestring{\_detokenize{#1}}"=="\_luaescapestring{\_detokenize{#2}}" then else tex.print("\_nbb unless") end}#3} \_public \isequal ; \_doc ---------------------------- \`\ismacro` `\macro{text}\iftrue` is true if macro is defined as {}. Category codes are ignored in this testing. The macro is expandable. \_cod ---------------------------- \_long\_def\_ismacro#1{\_ea\_isequal\_ea{#1}} \_public \ismacro ; \_doc ---------------------------- \`\isdefined` `{}\iftrue` is true if `\` is defined. The macro is expandable. \_cod ---------------------------- \_def\_isdefined #1#2{\_ifcsname #1\_endcsname \_else \_ea\_unless \_fi #2} \_public \isdefined ; \_doc ---------------------------- \`\isinlist` `\list{}\iftrue` is true if the `` is included the macro body of the `\list`. The category codes are relevant here. The macro is expandable. \_cod ---------------------------- \_long\_def\_isinlist#1#2{% \_immediateassignment\_long\_def\_isinlistA##1#2##2\_end/_% {\_if\_relax\_detokenize{##2}\_relax \_ea\_unless\_fi}% \_ea\_isinlistA#1\_endlistsep#2\_end/_% } \_public \isinlist ; \_doc ----------------------------- \`\isfile` `{}\iftrue` is true if the file exists and are readable by \TeX. \_cod ----------------------------- \_newread \_testin \_def\_isfile #1{% \_openin\_testin ={#1}\_relax \_ifeof\_testin \_ea\_unless \_else \_closein\_testin \_fi } \_public \isfile ; \_doc ----------------------------- \`\isfont` `{}\iftrue` is true if a given font exists. The result of this testing is saved to the \`\_ifexistfam`. \_cod ----------------------------- \_newifi \_ifexistfam \_def\_isfont#1#2{% \_begingroup \_suppressfontnotfounderror=1 \_font\_testfont={#1}\_relax \_ifx\_testfont\_nullfont \_def\_tmp{\_existfamfalse \_unless} \_else \_def\_tmp{\_existfamtrue}\_fi \_ea \_endgroup \_tmp #2% } \_public \isfont ; \_doc ---------------------------- The last macro \`\isnextchar` `{}{}` has a different syntax than all other is-macros. It executes `` if next character is equal to . Else the `` is executed. The macro is not expandable. \_cod ---------------------------- \_long\_def\_isnextchar#1#2#3{\_begingroup\_toks0={\_endgroup#2}\_toks1={\_endgroup#3}% \_let\_tmp= #1\_futurelet\_next\_isnextcharA } \_def\_isnextcharA{\_the\_toks\_ifx\_tmp\_next0\_else1\_fi\_space} \_public \isnextchar ; \_doc ---------------------------- \`\casesof` ` ` implements something similar to the `switch` command known from C language. It is expandable macro. The is a list of arbitrary number of pairs in the format ``\,`{}` which must be finalized by the pair `\_finc {}`. The optional spaces after s and between listed cases are ignored. The usage of \^`\casesof` looks like: \begtt \catcode`<=13 \casesof {} {} ... {} \_finc {} \endtt The meaning of tokens are compared by `\ifx` primitive. The parts `` can be finalized by a macro which can read more data from the input stream as its parameters. \_cod ---------------------------- \_long\_def \_casesof #1#2#3{\_ifx #2\_finc \_ea\_ignoresecond \_else \_ea\_usesecond \_fi {#3}{\_ifx#1#2\_ea\_ignoresecond \_else \_ea\_usesecond \_fi {\_finc{#3}}{\_casesof#1}}% } \_long\_def \_finc #1#2\_finc#3{#1} \_public \casesof ; \_doc ----------------------------- \`\xcasesof` `` extends the features of the macro \^`\casesof`. Each pair from the `` is in the format `{}{}`, only the last pair must have the different format: `\_finc {}`. The `` can be arbitrary primitive `\if*` condition (optionally prefixed by `\unless`) and it must be closed in its expansion. It means that `{\ifnum\mycount>0}` is bad, `{\ifnum\mycount>0 }` is correct. Optional spaces between parameters are ignored. Example: \begtt \message {The \tmpnum has \xcasesof {\ifnum\tmpnum>0 } {positive} {\ifnum\tmpnum=0 } {equal to zero} \_finc {negative} value} \endtt The \^`\xcasesof` macro works with principle: first true condition wins, next conditions are not evaluated. \_cod ----------------------------- \_long\_def \_xcasesof #1{\_xcasesofA #1\_finc} \_long\_def \_xcasesofA #1#2\_finc #3{% \_ifx #1\_finc \_ea\_ignoresecond\_else \_ea\_usesecond\_fi {#3}{#1#2\_ea\_ignoresecond\_else \_ea\_usesecond\_fi {\_finc{#3}}{\_xcasesof}}% } \_public \xcasesof ; \_endcode 2022-12-02 \xcasesof: its first parameter is \long too. 2022-11-29 renamed to \casesof, \xcasesof. 2022-11-26 \casesby, \casesbyif introduced. 2022-05-04 \isinlist created expandable. 2022-03-30 \afterfi defined as \long. 2021-08-02 more robust \fornum: \fi moved by \afterfi 2021-02-03 public version of \loop and \foreach are \long 2020-05-22 \foreach, \fornum: all settings are global, independent on TeX group 2020-05-06 \isnextchar: \let\tmp=#1 -> \let\tmp= #1 (bug fix, #1 should be space) 2020-05-02 \newif bug fix 2020-04-15 \fornumstep 3: 1..12 instead \fornum 1..12\step 3 2020-04-15 \fornum, \foreach can be nested without groups 2020-04-01 implemented