parser/scanner.lex

   1         #include <stdio.h>
   2         #include <stdlib.h>
   3         #include <string.h>
   4         #include "parser.h"
   5
   6 KEYWORD         func|end|struct|var|if|then|else|while|do|return|or|not
   7 SPECIAL_CHAR    \;|\.|\(|\)|\,|\:=|\-|\+|\*|>=|=
   8 IDENTIFIER      [[:alpha:]_][[:alnum:]_]*
   9 NUMBER_HEX      [0-9][0-9A-Fa-f]*H
  10 NUMBER_DEC      [0-9]+
  11 WHITESPACE      [\t\n\r ]
  12 COMMENT_START   \(\*
  13 COMMENT_END     \*\)
  14
  15 %x COMMENT
  16 %option yylineno
  17 %%
  18
  19 {COMMENT_START}                 BEGIN(COMMENT);
  20
  21 <COMMENT>{COMMENT_END}          BEGIN(INITIAL);
  22
  23 <COMMENT>{COMMENT_START}        fprintf(stderr, "Possibly nested comment on line %i\n", yylineno);
  24
  25 <COMMENT><<EOF>>                { fprintf(stderr, "Unterminated comment.\n"); exit(1); }
  26
  27 <COMMENT>{WHITESPACE}           /* ignore */
  28
  29 <COMMENT>.                      /* ignore everything inside comment */
  30
  31 func                            return(FUNC);
  32 end                             return(END);
  33 struct                          return(STRUCT);
  34 var                             return(VAR);
  35 if                              return(IF);
  36 then                            return(THEN);
  37 else                            return(ELSE);
  38 while                           return(WHILE);
  39 do                              return(DO);
  40 return                          return(RETURN);
  41 or                              return(OR);
  42 not                             return(NOT);
  43
  44 {IDENTIFIER}                    return(ID);
  45
  46 {NUMBER_DEC}                    return(NUM);
  47 {NUMBER_HEX}                    return(NUM);
  48
  49 \:=                             return(ASSIGN);
  50 >=                              return(GREATER);
  51 {SPECIAL_CHAR}                  return(yytext[0]);
  52
  53 {WHITESPACE}                    /* ignore */
  54
  55 .                               { fprintf(stderr, "Lexical error on line %i\n", yylineno); exit(1); }
  56
  57 %%
  58
  59