Шрифт:
"PHI", 1.61803398874989484820, /* golden ratio */
0, 0
};
static struct { /* Built-ins */
char *name;
double (*func);
} builtins[] = {
"sin", sin,
"cos", cos,
"atan", atan,
"log", Log, /* checks argument */
"log10", Log10, /* checks argument */
"exp", Exp, /* checks argument */
"sqrt", Sqrt, /* checks argument */
"int", integer,
"abs", fabs,
0, 0
};
init /* install constants and built-ins in table */
{
int i;
Symbol *s;
for (i = 0; consts[i].name; i++)
install(consts[i].name, VAR, consts[i].eval);
for (i = 0; builtins[i].name; i++) {
s = install(builtins[i].name, BLTIN, 0.0);
s->u.ptr = builtins[i].func;
}
}
3.3.5
math.c
#include <math.h>
#include <errno.h>
extern int errno;
double errcheck;
double Log(x)
double x;
{
return errcheck(log(x), "log");
}
double Log10(x)
double x;
{
return errcheck(log10(x), "log10");
}
double Sqrt(x)
double x;
{
return errcheck(sqrt(x), "sqrt");
}
double Exp(x)
double x;
{
return errcheck(exp(x), "exp");
}
double Pow(x, y)
double x, y;
return errcheck(pow(x,y), "exponentiation");
}
double integer(x)
double x;
{
return (double)(long)x;
}
double errcheck(d, s) /* check result of library call */
double d;
char *s;
{
if (errno == EDOM) {
errno = 0;
execerror(s, "argument out of domain");
}
else if (errno == ERANGE) {
errno = 0;
execerror(s, "result out of range");
}
return d;
}
3.3.6
symbol.c
#include "hoc.h"
#include "y.tab.h"
static Symbol *symlist = 0; /* symbol table: linked list */
Symbol *lookup(s) /* find s in symbol table */
char *s;
{
Symbol *sp;
for (sp = symlist; sp != (Symbol*)0; sp = sp->next)
if (strcmp(sp->name, s) == 0)
return sp;
return 0; /* 0 ==> not found */
}
Symbol *install(s, t, d) /* install s in symbol table */
char *s;
int t;