1 /* Make this with:  lex delatex.lex;  cc lex.yy.c -ll -o delatex */
2 L [A-Za-z]
3 %Start Display Math Normal Tag VerbPlus Bracket
4 %%
5 <Normal>\'	{yyleng--; yymore(); /* ignore apostrophes */}
6 <Normal>{L}+\\- {yyleng-=2; yymore(); /* ignore hyphens */}
7 <Normal>[a-zA-Z0-9_]+@[a-zA-Z0-9_.]+	;	/* ignore email addresses */
8 <Normal>[a-z]/[^A-Za-z] ; /* ignore single letter "words" */
9 <Normal>[A-Z]+	; /* ignore words all in uppercase */
10 <Normal>{L}+('{L}*)*{L}	{printf("%s\n",yytext); /* any other letter seq is a word */} 
11 <Normal>"%".*	; /* ignore comments */
12 <Normal>\\{L}+	; /* ignore other control sequences */
13 <Normal>"\\begin{"	BEGIN Tag; /* ignore this and up to next "}" */
14 <Normal>"\\bibitem{"	BEGIN Tag;
15 <Normal>"\\bibliography{"	BEGIN Tag;
16 <Normal>"\\bibstyle{"	BEGIN Tag;
17 <Normal>"\\cite{"	BEGIN Tag;
18 <Normal>"\\end{"		BEGIN Tag;
19 <Normal>"\\include{"	BEGIN Tag;
20 <Normal>"\\includeonly{"	BEGIN Tag;
21 <Normal>"\\input{"	BEGIN Tag;
22 <Normal>"\\label{"	BEGIN Tag;
23 <Normal>"\\pageref{"	BEGIN Tag;
24 <Normal>"\\ref{"		BEGIN Tag;
25 <Normal>"\\verb+"	BEGIN VerbPlus;
26 <Normal>"\\documentclass["	BEGIN Bracket;
27 <Normal>"\\documentclass{"	BEGIN Tag;
28 <Normal>"\\usepackage["	BEGIN Bracket;
29 <Normal>"\\usepackage{"	BEGIN Tag;
30 <Bracket>[^\]]	;
31 <Bracket>"]["	;
32 <Bracket>"]{"	BEGIN Tag;
33 <Bracket>"]"	BEGIN Normal;
34 <Tag>[^}]		; /* ignore things up to next "}" */
35 <Tag>"}"		BEGIN Normal;
36 <VerbPlus>[^+]	;	/* ignore thing up to next "+" */
37 <VerbPlus>"+"	BEGIN Normal;
38 <Normal>[0-9]+	; /* ignore numbers */
39 <Normal>"\\("		BEGIN Math; /* begin latex math mode */
40 <Math>"\\)"		BEGIN Normal; /* end latex math mode */
41 <Math>.|\\[^)]|\n	; /* ignore anything else in latex math mode */
42 <Normal>"\\["		BEGIN Display; /* now in Latex display mode */
43 <Display>[^$]|\\[^\]]	; /* ignore most things in display math mode */
44 <Display>"\\]"	BEGIN Normal; /* get out of Display math mode */
45 <Normal>\\.	; /* ignore other single character control sequences */
46 <Normal>\\\n	; /* more of the same */
47 <Normal>\n|.	; /* ignore anything else, a character at a time */
48 %%
49 #include <stdio.h>
50 #include <stdlib.h>
51 
52 int
53 main(int argc, char **argv)
54 {
55 	int i;
56 	
57 	if (argc==1) {
58 	    yyin = stdin;
59 	    BEGIN Normal; /* Starts yylex off in the right state */
60 	    yylex();
61 	    }
62 	else for (i=1; i<argc; i++) {
63 	    yyin = fopen(argv[i],"r");
64 	    if (yyin==NULL) {
65 		fprintf(stderr,"can't open %s\n",argv[i]);
66 		exit(1);
67 		}
68 	    BEGIN Normal; /* Starts yylex off in the right state */
69 	    yylex();
70 	    }
71 	exit(0);
72 }
73 int
74 yywrap(void)
75 {
76 	return 1;
77 }