From: Keith Packard <keithp@keithp.com>
Date: Fri, 1 Dec 2017 10:31:29 +0000 (+0100)
Subject: altos/lisp: Fix pairp builtin
X-Git-Tag: 1.8.3~1^2~33
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=796017262cd433af5d143cc7168c944e1e05f4e2

altos/lisp: Fix pairp builtin

Pairs are non-nil cons values; add an explicit check for nil here

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

diff --git a/src/lisp/ao_lisp_builtin.c b/src/lisp/ao_lisp_builtin.c
index 693cc3ca..f13f2180 100644
--- a/src/lisp/ao_lisp_builtin.c
+++ b/src/lisp/ao_lisp_builtin.c
@@ -675,7 +675,13 @@ ao_lisp_do_typep(int type, struct ao_lisp_cons *cons)
 ao_poly
 ao_lisp_do_pairp(struct ao_lisp_cons *cons)
 {
-	return ao_lisp_do_typep(AO_LISP_CONS, cons);
+	ao_poly	v;
+	if (!ao_lisp_check_argc(_ao_lisp_atom_led, cons, 1, 1))
+		return AO_LISP_NIL;
+	v = ao_lisp_arg(cons, 0);
+	if (v != AO_LISP_NIL && ao_lisp_poly_type(v) == AO_LISP_CONS)
+		return _ao_lisp_bool_true;
+	return _ao_lisp_bool_false;
 }
 
 ao_poly