scanner.l

/* scanner for a toy C language */
%{
/*
flex -o src/scanner.c src/scanner.l
gcc -g -o src/parser src/scanner.c -ll
./src/parser < test/input.c--
*/
#include <stdlib.h>
#include "node.h"
#include "analyzer.tab.h"

void yyerror(char *);
int row_cnt = 0;
int col_cnt = 0;
%}

INTEGER    [0-9]+
FLOAT      ([1-9][0-9]*)|0|([0-9]+\.[0-9]*)
ID         [_|A-Za-z]+(_|[A-Za-z]|[0-9])*
HD         #include<*.*>
AT         \/\*(.*)\*\/
DM         ,|;|\(|\)|\{|\}|\[|\]|\'|\"|<|>
STR        \".*?\"|\'.*?\'
%%
[\n]                  {
                        row_cnt ++; 
                      }
{HD}                  {} /* 系统保留字单独定义 */
"main"                return FUN;
                      return INT;
"double"              return DOUBLE;
"int"                 return INT;
"void"                return VOID;
"cin"                 return CIN; 
">>"                  return TO_RIGHT;
"cout"                return COUT;
"<<"                  return TO_LEFT;
">="                  return GE;
"<="                  return LE;
"=="                  return EQ;
"!="                  return NE;
"&&"                  return AND;
"||"                  return OR;
"while"               return WHILE;
"if"                  return IF;
"else"                return ELSE;
{ID}                  {
                        varNode * vp = searchVarTab(yytext);
                        if (vp == 0) 
                          vp = insertVarTab(yytext);
                        yylval.tptr = vp;
                        return VAR;
                      } /* 每遇到一个标识符就存入变量表 */
{INTEGER}             {
                        yylval.val = atof(yytext); 
                        return NUM;
                      }/*...*/
{FLOAT}               {
                        yylval.val = atof(yytext); 
                        return NUM;
                      }
[()<>=+\-/\*\;\{\}]   return *yytext;
[ \t]+                /* eat up whitespace */
.                     printf( "Unrecognized character: %s\n", yytext );

%%

varNode * insertVarTab (char * var_name)
{
  varNode *vp;
  vp = (varNode *) malloc (sizeof (varNode));
  vp->name = (char *) malloc (strlen (var_name) + 1); strcpy (vp->name, var_name);
  // vp->type = VAR;
  vp->value = 0; // 所有变量的默认值都是0
  /* 头插进变量表 */
  vp->next = (struct varNode *)var_table;
  var_table = vp;
  var_cnt ++;

  return vp;
}

int yywrap(void) {
  return 1;
}