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/*
* Copyright © 2016 Keith Packard <keithp@keithp.com>
*
* 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.
*/
#include "ao_lisp.h"
enum math_op { math_plus, math_minus, math_times, math_divide, math_mod };
ao_lisp_poly
ao_lisp_math(struct ao_lisp_cons *cons, enum math_op op)
{
ao_lisp_poly ret = AO_LISP_NIL;
while (cons) {
ao_lisp_poly car = cons->car;
uint8_t rt = ao_lisp_poly_type(ret);
uint8_t ct = ao_lisp_poly_type(car);
cons = cons->cdr;
if (rt == AO_LISP_NIL)
ret = car;
else if (rt == AO_LISP_INT && ct == AO_LISP_INT) {
int r = ao_lisp_poly_int(ret);
int c = ao_lisp_poly_int(car);
switch(op) {
case math_plus:
r += c;
break;
case math_minus:
r -= c;
break;
case math_times:
r *= c;
break;
case math_divide:
if (c == 0)
return AO_LISP_NIL;
r /= c;
break;
case math_mod:
if (c == 0)
return AO_LISP_NIL;
r %= c;
break;
}
ret = ao_lisp_int_poly(r);
}
else if (rt == AO_LISP_STRING && ct == AO_LISP_STRING && op == math_plus)
ret = ao_lisp_string_poly(ao_lisp_string_cat(ao_lisp_poly_string(ret),
ao_lisp_poly_string(car)));
else {
/* XXX exception */
return AO_LISP_NIL;
}
}
return ret;
}
ao_lisp_poly
ao_lisp_plus(struct ao_lisp_cons *cons)
{
return ao_lisp_math(cons, math_plus);
}
ao_lisp_poly
ao_lisp_minus(struct ao_lisp_cons *cons)
{
return ao_lisp_math(cons, math_minus);
}
ao_lisp_poly
ao_lisp_times(struct ao_lisp_cons *cons)
{
return ao_lisp_math(cons, math_times);
}
ao_lisp_poly
ao_lisp_divide(struct ao_lisp_cons *cons)
{
return ao_lisp_math(cons, math_divide);
}
ao_lisp_poly
ao_lisp_mod(struct ao_lisp_cons *cons)
{
return ao_lisp_math(cons, math_mod);
}
static const struct ao_lisp_builtin builtin_plus = {
.type = AO_LISP_BUILTIN,
.func = ao_lisp_plus,
.name = "+"
};
static const struct ao_lisp_atom atom_plus = {
.type = AO_LISP_ATOM,
.val = AO_LISP_OTHER_POLY(&builtin_plus),
.next = AO_LISP_ATOM_CONST,
.name = "plus"
};
/*
static const struct ao_lisp_builtin builtin_minus = {
.type = AO_LISP_BUILTIN,
.func = ao_lisp_minus
};
static const struct ao_lisp_builtin builtin_times = {
.type = AO_LISP_BUILTIN,
.func = ao_lisp_times
};
*/
const struct ao_lisp_atom const *ao_lisp_builtins[] = {
&atom_plus,
0
};
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