%{

/* chad c d clark   < clarkch @ cpsc . ucalgary . ca >
 *
 * cpsc 411	lec ??
 * winter 2002	lab 02
 *
 * assignment #1 - a first stab.
 *
 * file: as1lex.l
 * purpose: a basic lexer
 * 
 * assumtions:
 *    - all keywords are lowercase.
 *    - identifiers are case sensitive, start with an alphabetic character,
 *      and consist of alphabetic and numeric characters.
 *    - whitespace is to be ignored. (syntax oriented, not line oriented.)
 *
 */

#include "as1tokens.h"
#include "as1globals.h"
#include "as1tree.h"


%}


IF	"if"
THEN	"then"
WHILE	"while"
DO	"do"
UNTIL	"until"
READ	"read"
ELSE	"else"
BEGIN	"begin"
END	"end"
PRINT	"print"
ID	[a-zA-Z][0-9a-zA-Z]*
NUM	[0-9]+
ADD	"+"
SUB	"-"
MUL	"*"
DIV	"/"
LPAR	"("
RPAR	")"
SEMICOLON	";"
ASSIGN	":="
MULTISTART	"/*"
MULTIEND	"*/"


%x COMMENT

%%

{MULTISTART}		{BEGIN COMMENT;}
<COMMENT>{MULTIEND}	{BEGIN 0;}
<COMMENT>\n		{ /* multiline comment */ }
<COMMENT>.		{ /* multiline comment */ }

"%".*\n		{ /* single line comment */ }

[ ]	{ /* whitespace */ }
\t	{ /* whitespace */ }
\n	{ /* whitespace */ }

{IF}	{ return (T_IF); }
{THEN}	{ return (T_THEN); }
{WHILE}	{ return (T_WHILE); }
{DO}	{ return (T_DO); }
{UNTIL}	{ return (T_UNTIL); }
{READ}	{ return (T_READ); }
{ELSE}	{ return (T_ELSE); }
{BEGIN}	{ return (T_BEGIN); }
{END}	{ return (T_END); }
{PRINT}	{ return (T_PRINT); }
{ID}	{ return (T_ID); }
{NUM}	{ return (T_NUM); }
{ADD}	{ return (T_ADD); }
{SUB}	{ return (T_SUB); }
{MUL}	{ return (T_MUL); }
{DIV}	{ return (T_DIV); }
{LPAR}	{ return (T_LPAR); }
{RPAR}	{ return (T_RPAR); }
{SEMICOLON}	{ return (T_SEMICOLON); }
{ASSIGN}	{ return (T_ASSIGN); }
.	{ return (T_ERROR); }

%%


/* chad c d clark   < clarkch @ cpsc . ucalgary . ca >
 *
 * cpsc 411	lec ??
 * winter 2002	lab 02
 *
 * assignment #1 - a first stab.
 *
 * function: as1main.c
 * purpose: tests the lexer's return values.
 * 
 *
 */

struct stree_node * prog(void);

int main(int argc, char **argv) {

        struct stree_node *STree = NULL;

	if(!FINAL) printf("\n");

	curr_token = yylex();

	STree = prog();

	if(PRINT_STREE) {	/* see as1globals.h */
		printf("\nSyntax Tree:\n");
		print_stree(STree, 0);
	}

	/*
	* printf("\n\nSeaching for PRINT_NODE's ... ");
	* if (find_node(PRINT_NODE, STree))
	*	printf("success!\n");
	* else
	*	printf("failed!\n");
	*/

	if(!FINAL) printf("\nGenerated Code:\n");
	gen_code(STree);

	delete_stree(STree);

	if(!FINAL) printf("\n");
	return(0);
}