学步园

you will need the lastest versions of:

1. flex-2.5.4a-1.exe

2. bison-2.4.1-setup.exe

3. After that, do a full install in a directory of your preference without
   spaces in the name. I suggestC:\GnuWin32.
   Do not install
   it in the default (C:\Program
   Files (x86)\GnuWin32) because bison has problems with spaces in directory names, not to say parenthesis.

4. Also, consider installing Dev-CPP in
   the default directory (C:\Dev-Cpp)

5. After that, set the PATH variable to include the bin directories of gcc (in C:\Dev-Cpp\bin)
   andflex\bison (in C:\GnuWin32\bin).
   To do that, copy this: ;C:\Dev-Cpp\bin;C:\GnuWin32\bin and
   append it to the end of the PATH variable,
   defined in the place show by this figure:
   
   If the figure is not in good resolution, you can see a step-by-step
   here.

6. Open a prompt, cd to the directory where your ".l" and ".y" are, and compile them with:

   1. flex
hello.l
   2. bison
-dy hello.y
   3. gcc
lex.yy.c y.tab.c -o hello.exe

You will be able to run the program. I made the sources for a simple test (the infamous Hello
World):

Hello.l

  %{

  #include <stdlib.h>
  #include "y.tab.h"

  %}

  %%

  ("hi"|"oi")"\n"       { return HI;  }
  ("tchau"|"bye")"\n"   { return BYE; }
  .                     { yyerror();  }

  %%

  int main(void)
  {
     yyparse();
     return 0;
  }

  int yywrap(void)
  {
     return 0;
  }

  int yyerror(void)
  {
      printf("Error\n");
      exit(1);
  }

Hello.y