Add first lisp bits

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 132 insertions, 0 deletions

diff --git a/src/lisp/ao_lisp_poly.c b/src/lisp/ao_lisp_poly.c
new file mode 100644
index 00000000..1855d945
--- /dev/null
+++ b/src/lisp/ao_lisp_poly.c
@@ -0,0 +1,132 @@
+/*
+ * 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
+};