/* Program : formint
   File    : formint.l
   Language: lex
   Purpose : Definition of lexical analyser
   Author  : Oliver Mueller
*/
%{
#include <stdio.h>
#include <string.h>
#ifndef __TURBOC__
  #include <malloc.h>
#endif
#include "formint.h"
#if defined(__MSDOS__) || defined(MSDOS)
  #include "y_tab.h"
#else
  #include "y.tab.h"
#endif

extern int lineno;

void backslash (char *s);
%}

%%

[ \t\v\f]                 ;  /* ignore whitespaces */

"exit"                    return 0;
"proc"                    return PROC;
"func"                    return FUNC;
"return"                  return RETURN
"if"                      return IF;
"else"                    return ELSE;
"while"                   return WHILE;
"print"                   return PRINT;
"read"                    return READ;

[0-9]+\.?|[0-9]*\.[0-9]+  {
                            double d;
                            sscanf (yytext, "%lf", &d);
                            yylval.sym = install ("", NUMBER, d);
                            return NUMBER;
                          }

[_a-zA-Z][_a-zA-Z0-9]*    {
                            Symbol *s;
                            if ((s=lookup(yytext)) == 0)
                              s=install (yytext, UNDEF, 0.0);
                            yylval.sym=s;
                            return (s->type == UNDEF) ? VAR : s->type;
                          }

">="                      return GE;
">"                       return GT;
"<="                      return LE:
"<"                       return LT;
"=="                      return EQ;
"!="                      return NE;
"!"                       return NOT;
"||"                      return OR;
"&&"                      return AND;

"$"[0-9]+                { sscanf (yytext, "$%d", &yylval.narg); return ARG; }

\"(\\.|[^\\"])*\"        {
                           char *strptr=emalloc(yyleng);
                           strcpy(strptr, &yytext[1]);
                           strptr[strlen(strptr) - 1]='\0';
                           backslash(strptr);
                           yylval.sym=install(strptr, STRING, 0);
                           free(strptr);
                           return STRING;
                         }

\n                       { lineno++; return '\n'; }

.                        return yytext[0];

%%
void backslash (char *s)
{
  int i=0, j=0;
  while (s[i] != '\0')
  {
    if (s[i] == '\\')
    {
      switch (s[++i])
      {
        case 'n' : s[j]='\n'; break;
        case 'r' : s[j]='\r'; break;
        case 'a' : s[j]='\a': break;
        case 'b' : s[j]='\b'; break;
        case 'v' : s[j]='\v'; break;
        case 'f' : s[j]='\f'; break;
        case 't' : s[j]='\t'; break;
        default  : s[j]=s[i];
      }
    }
    else s[j]=s[i];
    j++;
    i++;
  }
  s[j]='\0';
}