iris

commit 65ae92823f2db07e31caf8df8fadf6c3154401e2
parent 975ef834508906247bda5ad2d1492213eff4c0bf
Author: sin <sin@2f30.org>
Date:   Thu, 15 May 2014 13:36:38 +0100

Add if handling

Diffstat:
M
parser.c
 | 
23
+++++++++++++++++++++++

1 file changed, 23 insertions(+), 0 deletions(-)
diff --git a/parser.c b/parser.c
@@ -60,6 +60,7 @@ struct object {
 };
 
 static struct object *evaldefine(struct object *);
+static struct object *evalif(struct object *);
 static struct object *evalok(struct object *);
 static struct object *evalquote(struct object *);
 static struct object *evalset(struct object *);
@@ -70,6 +71,7 @@ struct {
 	struct object *(*fn)(struct object *);
 } builtins[] = {
 	{ .name = "define", .fn = evaldefine },
+	{ .name = "if",     .fn = evalif     },
 	{ .name = "ok",     .fn = evalok     },
 	{ .name = "quote",  .fn = evalquote  },
 	{ .name = "set",    .fn = evalset    },
@@ -320,6 +322,27 @@ evaldefine(struct object *o)
 }
 
 static struct object *
+evalif(struct object *o)
+{
+	struct object *ocar;
+	struct object *predicate;
+
+	if (o->type != OPair)
+		return NULL;
+	ocar = car(o);
+	if (ocar->type != OIdentifier ||
+	    strcmp(ocar->d.i.s, "if") != 0)
+		return NULL;
+	predicate = eval(cadr(o));
+	if (predicate->type == OError)
+		return predicate;
+	if (predicate->type == OBoolean &&
+	    predicate->d.b.v == false)
+		return eval(cadddr(o));
+	return eval(caddr(o));
+}
+
+static struct object *
 evalok(struct object *o)
 {
 	if (o->type == OIdentifier)