/*
* pascal.lex: An example PASCAL scanner
*
*/
%{
#include <stdio.h>
#include "y.tab.h"
int line_number = 0;
void yyerror(char *message);
%}
%x COMMENT1 COMMENT2
white_space [ \t]*
digit [0-9]
alpha [A-Za-z_]
alpha_num ({alpha}|{digit})
hex_digit [0-9A-F]
identifier {alpha}{alpha_num}*
unsigned_integer {digit}+
hex_integer ${hex_digit}{hex_digit}*
exponent e[+-]?{digit}+
i {unsigned_integer}
real ({i}\.{i}?|{i}?\.{i}){exponent}?
string \'([^'\n]|\'\')+\'
bad_string \'([^'\n]|\'\')+
%%
"{" BEGIN(COMMENT1);
<COMMENT1>[^}\n]+
<COMMENT1>\n ++line_number;
<COMMENT1><<EOF>> yyerror("EOF in comment");
<COMMENT1>"}" BEGIN(INITIAL);
"(*" BEGIN(COMMENT2);
<COMMENT2>[^)*\n]+
<COMMENT2>\n ++line_number;
<COMMENT2><<EOF>> yyerror("EOF in comment");
<COMMENT2>"*)" BEGIN(INITIAL);
<COMMENT2>[*)]
/* note that FILE and BEGIN are already
* defined in FLEX or C so they can't
* be used. This can be overcome in
* a cleaner way by defining all the
* tokens to start with TOK_ or some
* other prefix.
*/
and return(AND);
array return(ARRAY);
begin return(_BEGIN);
case return(CASE);
const return(CONST);
div return(DIV);
do return(DO);
downto return(DOWNTO);
else return(ELSE);
end return(END);
file return(_FILE);
for return(FOR);
function return(FUNCTION);
goto return(GOTO);
if return(IF);
in return(IN);
label return(LABEL);
mod return(MOD);
nil return(NIL);
not return(NOT);
of return(OF);
packed return(PACKED);
procedure return(PROCEDURE);
program return(PROGRAM);
record return(RECORD);
repeat return(REPEAT);
set return(SET);
then return(THEN);
to return(TO);
type return(TYPE);
until return(UNTIL);
var return(VAR);
while return(WHILE);
with return(WITH);
"<="|"=<" return(LEQ);
"=>"|">=" return(GEQ);
"<>" return(NEQ);
"=" return(EQ);
".." return(DOUBLEDOT);
{unsigned_integer} return(UNSIGNED_INTEGER);
{real} return(REAL);
{hex_integer} return(HEX_INTEGER);
{string} return{STRING};
{bad_string} yyerror("Unterminated string");
{identifier} return(IDENTIFIER);
[*/+\-,^.;:()\[\]] return(yytext[0]);
{white_space} /* do nothing */
\n line_number += 1;
. yyerror("Illegal input");
%%
void yyerror(char *message)
{
fprintf(stderr,"Error: \"%s\" in line %d. Token = %s\n",
message,line_number,yytext);
exit(1);
}