#include"global.h"
#include"lexer.h"
#include"symbol.h"
#include"error.h"
char lexbuf[BSIZE];
int lineno=1;
float tokenval=(float)NONE;

int lexan(){
   int t; 
   while(1){
         t=getchar();
         if  (t==' '||t=='\t') ;
         else if  (t=='\n')  lineno++;
         else if  (isdigit(t)){
            ungetc(t,stdin);  
            scanf("%f",&tokenval);
            return NUM;
          }
		 else if  (isalpha(t)){
           int p,b=0;
           while(isalnum(t)){
                 lexbuf[b]=t;  t=getchar();b=b+1;
                 if(b>BSIZE)
					 error("complier error");
           }
           lexbuf[b]=EOS;
           if(t!=EOF)   ungetc(t,stdin);
           p=lookup(lexbuf);
           if(p==0)  p=insert(lexbuf,ID);
           tokenval=(float)p;
           return (int)symtable[p].token;
		 }
		 else if(t==EOF)
			 return DONE;
		 else {
			 tokenval=(float)NONE;
			 return t;
		 }
		 }
}