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\section[De-at-ifier]{Handles `at' and `tr' shorthands}

[Taking over from lit-inputter, minus the LITINPUTS stuff]

Has to know whether \tr{lit2pgm}, \tr{lit2latex} or \tr{lit2texi}
(grabbed from deviously-passed command-line argument).

And makes index entries appear well-behaved (same as \tr{\tr}, really).

And nukes [most] comments (sigh).

\subsection[deatify_Definitions]{Lex definitions}

Here, we use \tr{lex} ``start conditions'' a lot; we keep a stack of
them and manipulate them in a fairly obvious way.  Using start
conditions like this gives you ``mini-lexers'' within the overall
lexer.
\begin{code}
%{
#define LEX_STK_SIZE 256

int lex_stk[LEX_STK_SIZE];
int lex_stk_top = 0;

#define PUSH(x)    	   lex_stk[++lex_stk_top] = (x); BEGIN(x)
#define POP        	   BEGIN(lex_stk[--lex_stk_top])
#define LEX_STK_TOP	   lex_stk[lex_stk_top]
#define LEX_NEXT_TO_STK_TOP lex_stk[lex_stk_top - 1]
#define CHG_TOP(x)	   lex_stk[lex_stk_top] = (x); BEGIN(x)
#define CHG_NEXT_TO_TOP(x) lex_stk[lex_stk_top - 1] = (x)
/* not a lot in the old stack {over,under}flow dept, what? */

extern char *yytext; /* forward decl */
void print_leading_whitespace();

void
print_lex_stk () /* just for debugging */
{
    int i;
    fprintf(stderr,"lex_stk:");
    for (i = lex_stk_top; i >= 0; i--) {
        fprintf(stderr," %d",lex_stk[i]);
    }
    fprintf(stderr,"::%s\n",yytext);
}
\end{code}

Things related to handling \tr{\input} commands (not doing this at the
moment):
\begin{code}
int verbose;	   /* set from first argv */
int follow_inputs; /* set from second argv */

#if defined (SYSV) || defined (SYSV)
#include <string.h>
#include <time.h>
#else
#include <strings.h>
#include <sys/time.h>
#endif

#if defined (SYSV)
#define index(string, ch) strchr ((string), (ch))
#endif

#define INPUTFILE_STK_SIZE 20
struct {
    YY_BUFFER_STATE handle; /* flex-supplied magic */
    char* 	    name;
    int   	    lineno;
} inputfile_stk[INPUTFILE_STK_SIZE];
int   inputfile_stk_top = 0;
void  push_inputfile();
void  pop_inputfile();
int   i; /* temporary */
char* rbrace;
\end{code}

\begin{code}
int deatify_debug       = 0;
int unmatched_lbraces   = 0;
int unmatched_lbrackets = 0;

/* like everything, must track srcfile name and lineno */
char srcfile_name[1024]; /* too lazy to do this right */
int  lineno = 1; /* count \n's as they go by */
int  lineno_fiddled = 0; /* boolean: incr if newlines get trashed */

int  exit_status = 0;
void not_OK ();  /* prints an error msg and bumps exit_status */
void warning (); /* same, but no exit-status fiddling */

int lit2what; /* set from ARGV */

#define IS_LIT2PGM_Q	(lit2what == 1)
#define IS_LIT2PGM	(lit2what == 2)
#define IS_LIT2TEXI	(lit2what == 3)
#define IS_LIT2LATEX	(lit2what == 4)
#define IS_LIT2DEPEND	(lit2what == 5)
#define IS_LIT2CHANGELOG (lit2what== 6)

/* the condition for printing to stdout */
#define SHLD_PRINT	(! IS_LIT2PGM_Q || (LEX_STK_TOP == Code || LEX_STK_TOP == Bird))

void myecho();
#define MYECHO myecho()
void myprintstr();

#define YY_USER_ACTION if (deatify_debug) print_lex_stk(); /* debugging */
%}
D		[0-9]+
END_WORD	[-~/!\?(),\.'`A-Za-z0-9]*[ \t]*

%x Norm Verb Code Bird Atting Math Index Typing Linify_braces Linify_brackets
%%
	CHG_TOP(Norm); /* that's where we start */
\end{code}

\subsection[deatify_Rules]{Lex rules}

We start as @<Norm>@ and branch off to one of the other
``mini-scanners'' when we see certain things.

First: some magic characters absolutely verboten in the input:
\begin{code}
[\001\002\003]		{ not_OK("ASCII chars \001, \002, \003 may not appear in literate files\n");
			  exit(1);
			}
\end{code}


% um... we're generating these here now...
% (sorry, wrongo, buddy)
First thing is the magic source-file tracking lines (only in
\tr{<Norm>}, I think):
\begin{code}
<Norm>^"srcfile!_!"(.+)"!_!"([0-9]+)"!_!"\n {
		  sscanf(yytext+10,"%[^!]!_!%d", srcfile_name, &lineno);
		  if (lineno > 0) {
		     ECHO;
		  }
		}
\end{code}

Now a bit of stuff to handle \tr{\input} lines:
\begin{code}
<Norm>^\\input\{[^\}\n]+\}.*\n		{ lineno++;
					  if (follow_inputs) {
					      /* nullify first right brace */
					      rbrace = index(yytext+7,'}');
					      *rbrace = '\0';
					      push_inputfile(yytext+7);
					  } else {
					      MYECHO;
					  }
					}
<Norm,Bird><<EOF>>	{ if ( inputfile_stk_top <= 0 ) {
			     yyterminate();
			  } else {
			     pop_inputfile();
			  }
			  CHG_TOP(Norm); /* revert */
			}
\end{code}


Code and verbatim stuff gets copied through absolutely unmangled,
using the @<Verb>@ (or almost equivalently @<Code>@) mini-scanner.
\begin{code}
<Norm>^\\begin\{verbatim\}.*\n		|
<Norm>^\\begin\{flushverbatim\}.*\n	|
<Norm>^\\begin\{pseudocode\}.*\n	{ lineno++; MYECHO; PUSH(Verb); /* some may have opt arg */ }
<Norm>^\\begin\{code\}.*\n	{ lineno++;
				  if (IS_LIT2PGM_Q) {
				      printf("srcfile!_!%s!_!%d!_!\n",srcfile_name,lineno);
				  }
				  MYECHO;
				  PUSH(Code);
				}
\end{code}

Then there's the \tr{>} business; the ugliest way ever invented for
writing programs.  You can only get there from \tr{<Norm>}, because I
said so.

\begin{code}
<Norm>\n[ \t]+\n\>	{ /* convert to something less weird & try again */
			  unput('>'); unput('\n'); unput('\n');
			}
<Norm>\n\n\>.*\n	{ lineno += 3;
			  /* NB: init > converted to space */
			  if (IS_LIT2PGM_Q) {
			      printf("srcfile!_!%s!_!%d!_!\n",srcfile_name,(lineno-1));
			      printf("%s",yytext+3);
			  } else {
			      ECHO;
			  }
			  PUSH(Bird);
			}
<Norm>\n\>.*\n		{ lineno++; /* so msg will have right line # */
			  if (lineno > 2) /* I feel guilty about this hack */
			      /* to avoid: file is: blank lines, then code */
			      not_OK("Bird-style code not preceded by a blank line\n");
			  lineno++; /* account for other \n */
			  if (IS_LIT2PGM_Q) {
			      printf("srcfile!_!%s!_!%d!_!\n",srcfile_name,(lineno-1));
			      printf("%s",yytext+2);
			  } else {
			      ECHO;
			  }
			  PUSH(Bird);
			}
<Norm>^\>.*\n		{ lineno++; /* first line of file */
			  if (IS_LIT2PGM_Q) {
			      printf("srcfile!_!%s!_!%d!_!\n",srcfile_name,(lineno-1));
			      printf("%s",yytext+1);
			  } else {
			      ECHO;
			  }
			  PUSH(Bird);
			}
\end{code}

There are a few macros (\tr{\section}, \tr{\author}, and the others
below) that may have funny \tr{@...@}'s, etc., in them (meaning
newlines would be inserted normally); these newlines must be
suppressed!  These macros send us off to \tr{<Linify_braces>} or
\tr{<Linify_brackets>}, which are like \tr{<Norm>} except that the
\tr{unput} newlines (below) get munched.  (This is getting really
horrible...)

\begin{code}
<Norm>\\author\{		{ MYECHO; PUSH(Linify_braces); }
<Norm>\\caption\{		{ MYECHO; PUSH(Linify_braces); }
<Norm>\\centerline\{		{ MYECHO; PUSH(Linify_braces); }
<Norm>\\date\{			{ MYECHO; PUSH(Linify_braces); }
<Norm>\\define\{		{ MYECHO; PUSH(Linify_braces); }
<Norm>\\heading\{		{ MYECHO; PUSH(Linify_braces); }
<Norm>\\label\{			{ MYECHO; PUSH(Linify_braces); }
<Norm>\\menuentry\{		{ MYECHO; PUSH(Linify_braces); }
<Norm>\\node\{			{ MYECHO; PUSH(Linify_braces); }
<Norm>\\owner\{			{ MYECHO; PUSH(Linify_braces); }
<Norm>\\[sub]*section{D}?\{	{ MYECHO; PUSH(Linify_braces); }
<Norm>\\[sub]*section{D}?\[	{ MYECHO; PUSH(Linify_brackets); }
<Norm>\\standaloneornot\{	{ MYECHO; PUSH(Linify_braces); }
<Norm>\\title\{			{ MYECHO; PUSH(Linify_braces); }
<Norm>\\(tr|pl)\{		{ MYECHO; unmatched_lbraces = 1; PUSH(Typing);
				  /* \tr has braces as literals */
				}
<Norm>\\item\[			{ MYECHO; PUSH(Linify_brackets); }
\end{code}

Similarly, an \tr{@} sends us off to @<Atting>@.  Of course, a \tr{\@} doesn't.
\begin{code}
<Norm>\\@			{ MYECHO; }
<Norm>@				{ myprintstr("\\codeInText{"); PUSH(Atting); }
\end{code}

Simple math mode stuff.

\begin{code}
<Norm>\\\$			{ MYECHO; }
<Norm>\$			{ myprintstr("\\MathMode{"); PUSH(Math); }
\end{code}

For index commands, we want them to be at the beginning of a line (we do?);
hence the @printf@'s here.  The internal magic is done by
@<Index>@.
\begin{code}
<Norm>\\index\{		{ MYECHO;
			  unmatched_lbraces = 1;
                          PUSH(Index);
                        }
\end{code}

The rest of the @<Norm>@ mini-scanner handles comments and echoes
everything else.
\begin{code}
<Norm>\\\{			{ MYECHO; }
<Norm>\\\}			{ MYECHO; }
<Norm,Math>\\%			{ MYECHO; }
<Norm,Math>\%.*\n[ \t]*\n>	{ /* technically this Bird-style code is wrong
				     (no blank line in front of it, but that's
				     not intuitively obvious to the casual observer).
				     Solution? A hack!
				  */
				  unput('>'); unput('\n'); unput('\n');
				}
<Norm,Math>\%.*\n		{ /* throw away */ lineno++;
				  if (! IS_LIT2PGM_Q)
				     printf("\nsrcfile!_!%s!_!%d!_!\n",srcfile_name,lineno);
				}
<Norm>[A-Za-z0-9 \t]+		{ MYECHO; /* slight efficiency */ }
<Norm>.				{ MYECHO; }
<Norm>\n			{ /* handle line-number fiddling */
				  MYECHO;
				  lineno++;
				  if (lineno_fiddled) {
				      if (! IS_LIT2PGM_Q)
				         printf("srcfile!_!%s!_!%d!_!\n",srcfile_name,lineno);
				      lineno_fiddled = 0;
				  }
				}
\end{code}

The \tr{<Verb>} and \tr{<Code>} mini-scanners pass everything through until it sees an
\tr{\end <something>}.  As it stands, the \tr{<something>} doesn't
have to be what was \tr{\begun} (bug).
\begin{code}
<Verb>^\\end\{verbatim\}	|
<Verb>^\\end\{flushverbatim\}	|
<Verb>^\\end\{pseudocode\}	{ MYECHO; POP; }
<Code>^\\end\{code\}		{ if (! IS_LIT2PGM_Q) ECHO; POP; }
<Verb,Code>^[^\\\n].*\n		{ lineno++; MYECHO; /* a line not started by \ */}
<Verb,Code>.			{ MYECHO; }
<Verb,Code>\n			{ lineno++; MYECHO; }
<Verb,Code><<EOF>>		{ not_OK("unexpected end-of-file in verbatim text or (pseudo)code\n");
				  exit(1);
				}
\end{code}

The \tr{<Bird>} mini-scanner is here only to check for
no-blank-line-after errors in uglyly-written code.
\begin{code}
<Bird>[ \t\n]*\n\>.*\n?	{ /* whitespace/blank-lines do not matter */
			  /* count lines... */
			  for (i = 0; i < strlen(yytext); i++) {
			      if (yytext[i] == '\n')
			      	  lineno++;
			  }
			  if (! IS_LIT2PGM_Q) {
			    ECHO;
			  } else { /* don't print leading whitestuff */
			      for (i = 0; i < strlen(yytext) && yytext[i] != '>'; i++)
				  ; /* no-op */
			      /* report where this got us...*/
			      printf("srcfile!_!%s!_!%d!_!\n",srcfile_name,
				((yytext[yyleng-1] == '\n') ? (lineno-1) : lineno));
			      /* putchar(' '); convert leading > to space */
			      for ( i++ ; i < strlen(yytext); i++)
				  putchar(yytext[i]);
			  }
			}
<Bird>^\>.*\n?		{ if (yytext[yyleng-1] == '\n') { lineno++; }
			  if (IS_LIT2PGM_Q) printf("%s",yytext+1); else ECHO;
			}
<Bird>[ \t]*\n		{ lineno++;
			  if ( ! IS_LIT2PGM_Q) ECHO;
			  POP;
			}
<Bird>.			{ lineno--; /* to get right # on msg */
			  not_OK("Bird-style code not followed by a blank line\n");
			  lineno++; /* put it back */
			  unput(yytext[0]);
			  POP;
			}
\end{code}

\tr{<Typing>} and \tr{<Index>} deal with braces the same way: these
rules must come before the default rules for \tr{<Typing>.} and
\tr{<Index>.}.

The rule of the @<Atting>@ game is to send everything through except
right braces and newlines (which break the use of @/[^\}]+/@ regexps).
No longer worry about one per line.

\begin{code}
<Atting>@@		{ myprintstr("@"); }
<Atting>@\\noindex\{\}	|
<Atting>@\\noindex	{ myprintstr("\001noindex\003}");
			  POP;
			}
<Atting>@		{ myprintstr("}");
			  POP;
			}
<Atting>\{		{ myprintstr("\001lbrace\003"); }
<Atting>\}		{ myprintstr("\001rbrace\003"); }
<Atting>\n		{ warning("I'm turning a newline inside a @...@ into a space\n");
			  myprintstr(" ");
			  lineno++;
			}

<Atting><<EOF>>		{ not_OK("unexpected end-of-file inside an @ ... @\n");
			  exit(1);
			}
<Atting>[A-Za-z0-9 \t]+	{ MYECHO; /* tiny efficiency */ }
<Atting>.		{ MYECHO; }
\end{code}

Math mode stuff.  At present, only extra work is to replace some
control sequences with plain text---for \tr{lit2texi} only.

\begin{code}
<Math>\\\$		{ MYECHO; }
<Math>\$		{ myprintstr("}");
			  POP;
			}
<Math>\{		{ myprintstr("\001lbrace\003"); }
<Math>\}		{ myprintstr("\001rbrace\003"); }
<Math>\n		{ myprintstr("\001newline\003");
			  lineno++;
			}

<Math><<EOF>>		{ not_OK("unexpected end-of-file inside $ ... $ (math mode)\n");
			  exit(1);
			}
<Math>[A-Za-z0-9 \t]+	{ MYECHO; /* tiny efficiency */ }
<Math>.			{ MYECHO; }
\end{code}

The braces/brackets stuff isn't too bad.  Well, there's the stuff for
\tr{\tr} and \tr{@..@}'s (no \tr{\index}'s now...) ...
\begin{code}
<Linify_braces,Linify_brackets>\\(tr|pl)\{ {
			  MYECHO;
			  unmatched_lbraces = 1;
			  PUSH(Typing);
			}

<Index,Linify_braces,Linify_brackets,Typing>\\\\ {
			  MYECHO;
			}
<Index,Linify_braces,Linify_brackets,Typing>\\ {
			  MYECHO;
			}
<Linify_braces,Linify_brackets>\\\{ {
			  MYECHO;
			}

<Linify_braces>\{	{ MYECHO; PUSH(Linify_braces); }
<Linify_brackets>\{	{ MYECHO; }

<Index,Typing>\{	{ unmatched_lbraces++; myprintstr("\001lbrace\003"); }

<Linify_braces,Linify_brackets>\\\} {
			  MYECHO;
			}
<Linify_braces>\}\{	{ /* next arg */ MYECHO; }

<Linify_braces>\}	{ MYECHO; POP; }
<Linify_brackets>\}	{ MYECHO; }

<Index,Typing>\}	{ if (--unmatched_lbraces == 0) {
			      MYECHO;
                              POP;
                          } else {
			      myprintstr("\001rbrace\003");
                          }
                        }

<Index,Linify_braces,Linify_brackets,Typing>\\@ {
			  MYECHO;
			}
<Linify_braces,Linify_brackets>@ {
			  myprintstr("\\codeInText{"); /* no newline */
			  PUSH(Atting); 
			}
<Typing>@		{ MYECHO; /* NB: magic <Index> chars below */ }

<Index,Linify_braces,Linify_brackets,Typing>\\\$ {
			  MYECHO;
			}
<Linify_braces,Linify_brackets>\$ {
			  myprintstr("\\MathMode{"); /* no newline */
			  PUSH(Math);
			}
<Index,Typing>\$	{ MYECHO; }

<Index,Linify_braces,Linify_brackets,Typing>\\% {
			  MYECHO;
			}
<Linify_braces,Linify_brackets>\%.*\n[ \t]*\n> {
			  /* see earlier comments about crimes against humanity */
			  unput('>'); unput('\n'); unput('\n');
			}
<Linify_braces,Linify_brackets>\%.*\n { /* throw away */
			  lineno++;
			  lineno_fiddled++;
			}
<Index,Typing>%		{ MYECHO; }

<Linify_brackets>\\\[	{ MYECHO; }
<Linify_brackets>\[	{ MYECHO; PUSH(Linify_brackets); }	

<Linify_brackets>\\\]	{ myprintstr("\\\001rbracket\003"); /* cannot have these in the way */ }
<Linify_brackets>\]\{	{ if (LEX_NEXT_TO_STK_TOP == Norm) {
			      MYECHO;
			  } else {
			      myprintstr("\001rbracket\003\{");
			      not_OK("WHAT'S GOING ON? ]{\n");
			      print_lex_stk();
			  }
			  CHG_TOP(Linify_braces);
                        }
<Linify_brackets>\]	{ if (LEX_NEXT_TO_STK_TOP == Norm) {
			      MYECHO;
			  } else {
			      myprintstr("\001rbracket\003");
			  }
			  POP;
                        }

<Index>\\\@		{ MYECHO; /* my pseudo-makeindex has two magic chars */ }
<Index>\@		{ myprintstr("\001idxsort\003"); }
<Index>\\!		{ MYECHO; }
<Index>\!		{ myprintstr("\001idxsubitem\003"); }

<Index,Linify_braces,Linify_brackets,Typing>\n {
			  lineno++;
			  lineno_fiddled++;
			  if (LEX_STK_TOP == Index) {
			     warning("I'm turning a newline inside an \\index{...} into a space\n");
			     myprintstr(" ");
			  } else if (LEX_STK_TOP == Typing) {
			     warning("I'm turning a newline inside a \\tr{...} or \\pl{...} into a space\n");
			     myprintstr(" ");
			  } else {
			     myprintstr("\001newline\003");
			  }
			}

<Index,Linify_braces,Linify_brackets,Typing>[A-Za-z0-9 \t]+ {
			  MYECHO; /* tiny efficiency */
			}

<Index,Linify_braces,Linify_brackets,Typing>. { MYECHO; /* catch all */ }

<Index><<EOF>>		{ not_OK("unexpected end-of-file inside an \\index{...}\n");
			  exit(1);
			}
<Linify_braces><<EOF>>	{ not_OK("unexpected end-of-file inside a macro argument\n");
			  exit(1);
			}
<Linify_brackets><<EOF>> {not_OK("unexpected end-of-file inside a macro optional argument\n");
			  exit(1);
			}
<Typing><<EOF>>		{ not_OK("unexpected end-of-file inside a \\tr{...}\n");
			  exit(1);
			}
\end{code}

Finally, we have a non-default @main@ routine because we need to pick
up the (mandatory) argument that says if we're doing pre-processing
for \tr{lit2pgm}, \tr{lit2latex}, or \tr{lit2texi}.
\begin{code}
%%

main(argc, argv)
int  argc;
char **argv;
{
    if (argc != 5) {
	fprintf(stderr,"Sorry, %s must have exactly 4 arguments\n", argv[0]);
	exit(1);
    }
    verbose	  = argv[1][0] - '0'; /* hacks */
    follow_inputs = argv[2][0] - '0';
    lit2what      = argv[3][0] - '0'; /* used in IS_LIT2xxx tests */
    if (strcmp(argv[4], "-") == 0) {
	yyin = stdin;
    } else if ((yyin = fopen(argv[4], "r")) == NULL) {
	fprintf(stderr,"%s: can't open file %s\n", argv[0], argv[4]);
	exit(1);
    }
    strcpy(srcfile_name, argv[4]);
    inputfile_stk[ inputfile_stk_top /* 0 */ ].name = argv[4];
    if ( ! IS_LIT2PGM_Q ) printf("srcfile!_!%s!_!1!_!\n",argv[4]);
    yylex();
    exit(exit_status);
}

void
push_inputfile (fname)
char* fname;
{
    if ( inputfile_stk_top >= INPUTFILE_STK_SIZE ) {
	fprintf(stderr,"\\input's too deeply nested\n");
	exit(1);
    }

    /* record where we are in current file */
    inputfile_stk[ inputfile_stk_top ].lineno   = lineno;
    inputfile_stk[ inputfile_stk_top ].handle = YY_CURRENT_BUFFER;
    /* actual push */
    inputfile_stk_top++;

    /* open new file fname */
    if ((yyin = fopen(fname, "r")) == NULL) {
	fprintf(stderr,"%s:%d: can't open \\input file %s\n", srcfile_name, lineno, fname);
	exit(1);
    }
    yy_switch_to_buffer( yy_create_buffer( yyin, YY_BUF_SIZE ) );

    /* report that's where we are */
    if (! IS_LIT2PGM_Q) printf("srcfile!_!%s!_!1!_!\n",fname);
    /* set srcfile_name and lineno for new file */

    strcpy(srcfile_name, fname); /* for my own tracking */
    lineno = 1;

    /* push/record everything for new file */
    inputfile_stk[ inputfile_stk_top ].name     = srcfile_name;
    inputfile_stk[ inputfile_stk_top ].lineno   = lineno;
}

void
pop_inputfile ()
{
    inputfile_stk_top--; /* actual pop */

    /* remind where we were */
    strcpy(srcfile_name, inputfile_stk[inputfile_stk_top].name);
    lineno       = inputfile_stk[inputfile_stk_top].lineno;
    /* put in an extra newline or two before the next file;
       otherwise, the cat'ting of files gives things like:

       > last line of code
       \section{Next section}

       which happens to be very bad for lit2stuff.
    */
    if (! IS_LIT2PGM_Q) printf("\n\nsrcfile!_!%s!_!%d!_!\n",srcfile_name,lineno);

    /* return to prev inputfile */
    yy_switch_to_buffer( inputfile_stk[inputfile_stk_top].handle );
}

void
myecho ()
{
    myprintstr(yytext);
}

void
myprintstr (str)
char *str;
{
    if (SHLD_PRINT) {
	printf("%s",str);
    }
}

void
print_leading_whitespace ()
{
    int i;
    
    for (i = 0; yytext[i] == ' ' || yytext[i] == '\t'; i++) {
    	putchar(yytext[i]);
    }
}

void
not_OK(msg)
char *msg;
{
    /* a good old emacsable error msg */
    fprintf(stderr,"%s:%d: %s", srcfile_name, lineno, msg);
    exit_status++;
}

void
warning(msg) /* exit_status not fiddled */
char *msg;
{
    /* a good old emacsable warning msg */
    fprintf(stderr,"%s:%d: [warning] %s", srcfile_name, lineno, msg);
}
\end{code}