%{

#include "parser.h"

%}

%option noyywrap
%option pointer

CT       "//"[^\n]*
WS       [ \n\r\t]+
ID       [_a-zA-Z][_a-zA-Z0-9]*
NUM      [0-9]+

%%

{CT}     {}
{WS}     {}

"mov"    { return INSTR_MOV; }
"add"    { return INSTR_ADD; }
"inc"    { return INSTR_INC; }
"jmp"    { return INSTR_JMP; }

"eax"    { return REG_EAX; }
"ebx"    { return REG_EBX; }
"ecx"    { return REG_ECX; }
"edx"    { return REG_EDX; }

{ID}     { return IDENTIFIER; }
{NUM}    { return NUMBER; }

","      { return COMMA; }
":"      { return COLON; }
";"      { return SEMICOLON; }

.        { yyerror("syntax error"); }

%{

#include <stdio.h>

int    yylex(void);
void   yyerror(const char *);
FILE * yyin;

%}

%token INSTR_MOV INSTR_ADD INSTR_INC INSTR_JMP
%token REG_EAX REG_EBX REG_ECX REG_EDX
%token IDENTIFIER NUMBER COMMA COLON SEMICOLON

%start program

%%

register_name
   : REG_EAX
   | REG_EBX
   | REG_ECX
   | REG_EDX
   ;

label
   : IDENTIFIER COLON
   ;

instruction_mov
   : INSTR_MOV register_name COMMA register_name SEMICOLON
   | INSTR_MOV register_name COMMA NUMBER SEMICOLON
   ;

instruction_add
   : INSTR_ADD register_name COMMA register_name COMMA register_name SEMICOLON
   | INSTR_ADD register_name COMMA register_name COMMA NUMBER SEMICOLON
   ;

instruction_inc
   : INSTR_INC register_name SEMICOLON
   ;

instruction_jmp
   : INSTR_JMP IDENTIFIER SEMICOLON
   ;

instruction
   : instruction_mov
   | instruction_add
   | instruction_inc
   | instruction_jmp
   ;

program
   : instruction
   | label
   | program instruction
   | program label
   ;

%%

void yyerror(const char * message)
{
   printf(message);
}

int main(int argc, char **argv)
{
   if(argc == 2)
   {
      if((yyin = fopen(argv[1], "rb")) != NULL)
      {
         yyparse();
         fclose(yyin);
      }
   }

   return 0;
}

// Some comment
start:
   mov eax, 10;
   mov ebx, 20;
   add ecx, eax, ebx;
   inc ecx;
   jmp start;