/* Make this with: lex delatex.lex; cc lex.yy.c -ll -o delatex */ L [A-Za-z] %Start Display Math Normal Tag VerbPlus Bracket %% <Normal>\' {yyleng--; yymore(); /* ignore apostrophes */} <Normal>{L}+\\- {yyleng-=2; yymore(); /* ignore hyphens */} <Normal>[a-zA-Z0-9_]+@[a-zA-Z0-9_.]+ ; /* ignore email addresses */ <Normal>[a-z]/[^A-Za-z] ; /* ignore single letter "words" */ <Normal>[A-Z]+ ; /* ignore words all in uppercase */ <Normal>{L}+('{L}*)*{L} {printf("%s\n",yytext); /* any other letter seq is a word */} <Normal>"%".* ; /* ignore comments */ <Normal>\\{L}+ ; /* ignore other control sequences */ <Normal>"\\begin{" BEGIN Tag; /* ignore this and up to next "}" */ <Normal>"\\bibitem{" BEGIN Tag; <Normal>"\\bibliography{" BEGIN Tag; <Normal>"\\bibstyle{" BEGIN Tag; <Normal>"\\cite{" BEGIN Tag; <Normal>"\\end{" BEGIN Tag; <Normal>"\\include{" BEGIN Tag; <Normal>"\\includeonly{" BEGIN Tag; <Normal>"\\input{" BEGIN Tag; <Normal>"\\label{" BEGIN Tag; <Normal>"\\pageref{" BEGIN Tag; <Normal>"\\ref{" BEGIN Tag; <Normal>"\\verb+" BEGIN VerbPlus; <Normal>"\\documentclass[" BEGIN Bracket; <Normal>"\\documentclass{" BEGIN Tag; <Normal>"\\usepackage[" BEGIN Bracket; <Normal>"\\usepackage{" BEGIN Tag; <Bracket>[^\]] ; <Bracket>"][" ; <Bracket>"]{" BEGIN Tag; <Bracket>"]" BEGIN Normal; <Tag>[^}] ; /* ignore things up to next "}" */ <Tag>"}" BEGIN Normal; <VerbPlus>[^+] ; /* ignore thing up to next "+" */ <VerbPlus>"+" BEGIN Normal; <Normal>[0-9]+ ; /* ignore numbers */ <Normal>"\\(" BEGIN Math; /* begin latex math mode */ <Math>"\\)" BEGIN Normal; /* end latex math mode */ <Math>.|\\[^)]|\n ; /* ignore anything else in latex math mode */ <Normal>"\\[" BEGIN Display; /* now in Latex display mode */ <Display>[^$]|\\[^\]] ; /* ignore most things in display math mode */ <Display>"\\]" BEGIN Normal; /* get out of Display math mode */ <Normal>\\. ; /* ignore other single character control sequences */ <Normal>\\\n ; /* more of the same */ <Normal>\n|. ; /* ignore anything else, a character at a time */ %% #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { int i; if (argc==1) { yyin = stdin; BEGIN Normal; /* Starts yylex off in the right state */ yylex(); } else for (i=1; i<argc; i++) { yyin = fopen(argv[i],"r"); if (yyin==NULL) { fprintf(stderr,"can't open %s\n",argv[i]); exit(1); } BEGIN Normal; /* Starts yylex off in the right state */ yylex(); } exit(0); } int yywrap(void) { return 1; }