/*
    This file is part of exprparser, a lex/yacc based expression parser
    Copyright (C) 2002-6 Toby Thain, toby@telegraphics.com.au

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by  
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License  
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <stdio.h>
#include <math.h>

#include "node.h"
#include "y.tab.h"

// example predefined constants
double t=.123, u=.456, v=.789, s[8], pi = M_PI;

// example predefined functions
double fxy(double x,double y){ return x*y; }
double fxyz(double x,double y,double z){ return x*y*z; }

extern struct node *parseformula(char*);

/* predefined symbols */
struct sym_rec predefs[]={
	/* variables */
	{0,TOK_VAR,"t", 0,0,0, &t},
	{0,TOK_VAR,"u", 0,0,0, &u},
	{0,TOK_VAR,"v", 0,0,0, &v},
	{0,TOK_VAR,"s0", 0,0,0, &s[0]},
	{0,TOK_VAR,"s1", 0,0,0, &s[1]},
	{0,TOK_VAR,"s2", 0,0,0, &s[2]},
	{0,TOK_VAR,"s3", 0,0,0, &s[3]},
	{0,TOK_VAR,"s4", 0,0,0, &s[4]},
	{0,TOK_VAR,"s5", 0,0,0, &s[5]},
	{0,TOK_VAR,"s6", 0,0,0, &s[6]},
	{0,TOK_VAR,"s7", 0,0,0, &s[7]},
	/* constants */
	{0,TOK_VAR,"PI", 0,0,0, &pi},
	/* functions */
	{0,TOK_FN1,"sin", &sin,0,0, 0}, // library functions...
	{0,TOK_FN1,"cos", &cos,0,0, 0},
	{0,TOK_FN1,"tan", &tan,0,0, 0},
	{0,TOK_FN1,"exp", &exp,0,0, 0},
	{0,TOK_FN1,"log", &log,0,0, 0},
	{0,TOK_FN1,"log10", &log10,0,0, 0},
	{0,TOK_FN1,"sqrt", &sqrt,0,0, 0},
	{0,TOK_FN2,"fxy", 0,&fxy,0, 0}, /* example 2-arg function */
	{0,TOK_FN3,"fxyz", 0,0,&fxyz, 0}, /* example 3-arg function */
	{NULL,0,NULL, NULL,NULL,NULL, NULL}
};

int main(int argc,char *argv[]){
	extern int tokpos;
	extern char *errstr;
	struct node *tree;
	char expr[0x100];
	int varused[26],i,varcount;

	init_symtab(predefs);

	while( fgets(expr,sizeof(expr),stdin) ){
		tokpos = 0;
		if( (tree = parseformula(expr)) ){
			dumptree(tree,0);
			printf("= %g\n",eval(tree));

			checkvars(tree,varused);
			printf("single character variables used: ");
			for(i=varcount=0;i<26;++i)
				if(varused[i]){
					if(varcount) putchar(',');
					putchar(i+'a');
					++varcount;
				}
			if(!varcount) printf("(none)");
			putchar('\n');
		}else
			printf("%*s\n%s\n",tokpos,"^",errstr);

		freetree(tree); // we're done with the parse tree
	}
	return EXIT_SUCCESS;
}