iris

commit dcfba9294a0d4077eecf724686a858676711e642
parent 85261cadcde2f1b41211dd666c2caec6732a204a
Author: sin <sin@2f30.org>
Date:   Wed, 14 May 2014 14:14:19 +0100

Implementation quotation

Diffstat:
M
parser.c
 | 
40
++++++++++++++++++++++++++++++++++++++--

1 file changed, 38 insertions(+), 2 deletions(-)
diff --git a/parser.c b/parser.c
@@ -18,6 +18,7 @@ enum objtype {
 	OString,
 	OEmptylist,
 	OPair,
+	OQuote,
 };
 
 struct object {
@@ -189,6 +190,16 @@ pair(FILE *in)
 }
 
 struct object *
+quote(void)
+{
+	struct object *o;
+
+	o = newobject();
+	o->type = OQuote;
+	return o;
+}
+
+struct object *
 sexpression(FILE *in)
 {
 	struct tok t;
@@ -216,6 +227,8 @@ sexpression(FILE *in)
 		return string(l);
 	case TLparen:
 		return pair(in);
+	case TQuote:
+		return cons(quote(), cons(sexpression(in), emptylist()));
 	default:
 		return error("unhandled token");
 	}
@@ -223,18 +236,41 @@ sexpression(FILE *in)
 	return NULL;
 }
 
+int
+quoted(struct object *o)
+{
+	struct object *car;
+
+	if (o->type == OPair) {
+		car = o->d.p.car;
+		return car->type == OQuote;
+	}
+	return 0;
+}
+
 struct object *
 eval(struct object *o)
 {
 	struct object *otmp;
 
+	switch (o->type) {
+	/* self-evaluating objects */
+	case OError:
+	case OEof:
+	case OBoolean:
+	case ONumber:
+	case OCharacter:
+	case OString:
+		return o;
+	}
 	if (o->type == OIdentifier) {
 		otmp = lookupsym(o->d.s.s);
 		if (!otmp)
 			return error("unbound identifier");
 	}
-	/* self-evaluating objects */
-	return o;
+	if (quoted(o))
+		return o->d.p.cdr->d.p.car; /* cadr */
+	return error("cannot eval object");
 }
 
 static void