examples/calc++/calc++-scanner.ll

   1 %{                                                            /* -*- C++ -*- */
   2
   3 # include <string>
   4 # include <cerrno>
   5 # include "calc++-driver.hh"
   6 # include "calc++-parser.hh"
   7 %}
   8
   9 %option noyywrap nounput debug batch
  10
  11 id    [a-zA-Z][a-zA-Z_0-9]*
  12 int   [0-9]+
  13 blank [ \t]
  14
  15 %%
  16
  17 %{
  18 # define YY_USER_ACTION  yylloc->columns (yyleng);
  19   yylloc->step ();
  20 %}
  21 {blank}+   yylloc->step ();
  22 [\n]+      yylloc->lines (yyleng); yylloc->step ();
  23
  24
  25 [-+*/]     return yytext[0];
  26 ":="       return TOKEN_ASSIGN;
  27 {int}      yylval->ival = atoi (yytext); return TOKEN_NUMBER;
  28 {id}       yylval->sval = new std::string (yytext); return TOKEN_IDENTIFIER;
  29 .          driver.error (*yylloc, "invalid character");
  30
  31 %%
  32
  33 void
  34 calcxx_driver::scan_begin ()
  35 {
  36   yy_flex_debug = trace_scanning;
  37   if (!(yyin = fopen (file.c_str (), "r")))
  38     error (std::string ("cannot open ") + file);
  39 }
  40
  41 void
  42 calcxx_driver::scan_end ()
  43 {
  44   fclose (yyin);
  45 }