/* Reverse polish notation calculator using
   Bison's semantic parser option. */

%{
/* Must define the following: */
#if 0
yyrecover
yymsg
yyabort
timeclock
#endif

#include <time.h>

#ifndef YYLTYPE
struct mytype {
	clock_t timestamp;
	int first_line, last_line, first_column, last_column;
	char* text;
};
typedef struct mytype mytype;
#define YYLTYPE mytype
#endif

#define YYSTYPE double
#include <math.h>

int yylex();

#define YYABORT return -1
#define YYACCEPT return 0

%}

%semantic_parser

%token NUM

%%

input: 	/* empty */
	 | input line
;

line: '\n'
	| exp '\n' { printf ("\t%.10g\n", $1); }
;

exp:  NUM { $$ = $1; }
	| exp exp '+' { $$ = $1 + $2; }
	| exp exp '-' { $$ = $1 - $2; }
	| exp exp '*' { $$ = $1 * $2; }
	| exp exp '/' { $$ = $1 / $2; }
	  /* Exponentiation */
	| exp exp '^' { $$ = pow ($1, $2); }
	  /* Unary minus */
	| exp 'n' { $$ = -$1; }
;

%%




/* Lexical analyzer returns a double floating point
   number on the stack and the token NUM, or the
   ASCII character read if not a number. Skips all
   blanks and tabs, returns 0 for EOF. */

#include <ctype.h>
#include <stdlib.h>

int yylex() {
	int c;
	/* skip white space */
	while ((c = getchar ()) == ' ' || c == '\t')
		;
	/* process numbers */
	if (c == '.' || isdigit (c)) {
		ungetc (c, stdin);
		scanf ("%lf", &yylval);
		return NUM;
	}
	/* return end-of-file */ if (c == EOF)
	return 0;
	/* return single chars */
	return c;
}

#if __MWERKS__ && macintosh
#include <SIOUX.h>
#endif

int timeclock;

char * yymsg = "I'm not feeling right.\n";

int main() {
#if __MWERKS__ && macintosh
	SIOUXSettings.asktosaveonclose = 0;
	SIOUXSettings.autocloseonquit = 0;
#endif
	timeclock = clock();
	return yyparse();
}


int yyrecover() { }

int yyabort(char* errstr) {
	printf("Error: %s\n", errstr);
	return EXIT_SUCCESS;
}


#if 0
int yyerror(char* errstr) {
	printf("Error: %s\n", errstr);
	printf("(Exit)\n");
	exit(EXIT_FAILURE);
	return EXIT_SUCCESS;
}
#endif