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/* $Id: expression.c,v 1.3 2003/10/06 05:51:15 reinelt Exp $
*
* expression handling
*
* Copyright 2003 Michael Reinelt <reinelt@eunet.at>
*
* This file is part of LCD4Linux.
*
* LCD4Linux 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, or (at your option)
* any later version.
*
* LCD4Linux 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*
* $Log: expression.c,v $
* Revision 1.3 2003/10/06 05:51:15 reinelt
* functions: min(), max()
*
* Revision 1.2 2003/10/06 05:47:27 reinelt
* operators: ==, \!=, <=, >=
*
* Revision 1.1 2003/10/06 04:34:06 reinelt
* expression evaluator added
*
*/
/*
* exported functions:
*
* int EX_init (void)
* initializes the expression evaluator
* adds some handy constants and functions
*
*/
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <string.h>
#include "debug.h"
#include "cfg.h"
#include "evaluator.h"
#include "expression.h"
static void my_sqrt (RESULT *result, RESULT *arg1)
{
double value=sqrt(R2N(arg1));
SetResult(&result, R_NUMBER, &value);
}
static void my_exp (RESULT *result, RESULT *arg1)
{
double value=exp(R2N(arg1));
SetResult(&result, R_NUMBER, &value);
}
static void my_ln (RESULT *result, RESULT *arg1)
{
double value=log(R2N(arg1));
SetResult(&result, R_NUMBER, &value);
}
static void my_log (RESULT *result, RESULT *arg1)
{
double value=log10(R2N(arg1));
SetResult(&result, R_NUMBER, &value);
}
static void my_sin (RESULT *result, RESULT *arg1)
{
double value=sin(R2N(arg1));
SetResult(&result, R_NUMBER, &value);
}
static void my_cos (RESULT *result, RESULT *arg1)
{
double value=cos(R2N(arg1));
SetResult(&result, R_NUMBER, &value);
}
static void my_tan (RESULT *result, RESULT *arg1)
{
double value=tan(R2N(arg1));
SetResult(&result, R_NUMBER, &value);
}
static void my_min (RESULT *result, RESULT *arg1, RESULT *arg2)
{
double a1=R2N(arg1);
double a2=R2N(arg2);
double value=a1<a2?a1:a2;
SetResult(&result, R_NUMBER, &value);
}
static void my_max (RESULT *result, RESULT *arg1, RESULT *arg2)
{
double a1=R2N(arg1);
double a2=R2N(arg2);
double value=a1>a2?a1:a2;
SetResult(&result, R_NUMBER, &value);
}
static void my_strlen (RESULT *result, RESULT *arg1)
{
double value=strlen(R2S(arg1));
SetResult(&result, R_NUMBER, &value);
}
static void my_cfg (RESULT *result, RESULT *arg1)
{
char *value=cfg_get(R2S(arg1), "");
SetResult(&result, R_STRING, value);
}
int EX_init (void)
{
// set some handy constants
AddConstant ("Pi", M_PI);
AddConstant ("e", M_E);
// register some basic math functions
AddFunction ("sqrt", 1, my_sqrt);
AddFunction ("exp", 1, my_exp);
AddFunction ("ln", 1, my_ln);
AddFunction ("log", 1, my_log);
AddFunction ("sin", 1, my_sin);
AddFunction ("cos", 1, my_cos);
AddFunction ("tan", 1, my_tan);
// min, max
AddFunction ("min", 2, my_min);
AddFunction ("max", 2, my_max);
// register some basic string functions
AddFunction ("strlen", 1, my_strlen);
// config file access
AddFunction ("cfg", 1, my_cfg);
return 0;
}
int EX_test(int argc, char* argv[])
{
int ec;
char line[1024];
RESULT result = {0, 0.0, NULL};
printf("\nEE> ");
for(gets(line); !feof(stdin); gets(line)) {
ec=Eval(line, &result);
if (result.type==R_NUMBER) {
printf ("%g\n", R2N(&result));
} else if (result.type==R_STRING) {
printf ("<%s>\n", R2S(&result));
}
printf("EE> ");
}
return 0;
}
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