%{
/*********
 * Simple lexical analysis file - 
 *
 * Note: the use of token(INDEX) is only for Tokentrace - see
 * the routine yaccextras.c
 * also allows us to obtain a listing from lex */

#include "booldef.h"
#include "y-tab.h"

extern int token();
extern int DumpSymTab();
%}
letter                          [a-zA-Z_]
digit                           [0-9]
letter_or_digit                 [a-zA-Z_0-9]
white_space                     [ \t\n]
blank                           [ \t]
comment                         "--"[^\n]*\n
string                          \"([^\n\"]|\"\")*\"
other                           .

%%
"%%c"                           {token(NULL); Gencode           = !Gencode;}
"%%t"                           {token(NULL); Tokentrace        = !Tokentrace;}
"%%pr"                          {token(NULL); PtraceSem         = !PtraceSem;}
"%%ss"                          {token(NULL); Semstacktrace     = 
                                                        !Semstacktrace;}
"%%dmp"                         {token(NULL); DumpSymTab();}

[Rr][Ee][Aa][Dd][Ll][Nn]        return token( Readln );
[Ww][Rr][Ii][Tt][Ee]            return token( Write );
[Ww][Rr][Ii][Tt][Ee][Ll][Nn]    return token( Writeln );

[Ii][Ff]                        return token ( If );
[Tt][Hh][Ee][Nn]                return token ( Then );
[Ee][Nn][Dd]                    return token ( End ); 
"="                             return token ( Eqop );

":="                            return token( Assignop );
"("                             return token( Lparen );
")"                             return token( Rparen );
"+"                             return token( Plussym );
"-"                             return token( Minussym );
"*"                             return token( Mpysym );
"/"                             return token( Divsym );
","                             return token( Commasym );
";"                             return token( Termsym );

{letter}{letter_or_digit}*      return token( Id );
{digit}{digit}*                 return token( Iconst );
{white_space}{white_space}*     token(NULL);
{comment}                       token(NULL);
{string}                        return token( Strconst );
{other}                         /*return yytext[0];*/ lexerr();
%%
int lexerr()
/* inform user of error and return the string being scanned */
{
        fputs ("\nERROR in Lex: \n",stdout);
        fprintf (stdout,"%s\n",yytext);
}

/* Strip unwanted quotes from string in yytext; adjust yyleng */
int stripquotes (char * yytext)
{
  int frompos, topos = 0, numquotes = 2;

  for (frompos = 1; frompos < yyleng; frompos++)
  {
    if (yytext[frompos] == 0x22 && yytext[frompos+1] == 0x22)
    {
      yytext[topos++] = '\\'; 
      yytext[topos++] = yytext[frompos++];
    }
    else
      yytext[topos++] = yytext[frompos];
  }
  yyleng -= numquotes;
  yytext[yyleng] = '\0';
}