iris

commit 00d7556a1443ee2047887f20440320c459f1d272
parent 76e8179b214bea8c00515956c1602522caa759b6
Author: sin <sin@2f30.org>
Date:   Fri, 16 May 2014 15:23:41 +0100

Add car, cdr and cons

Diffstat:
M
parser.c
 | 
59
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1 file changed, 59 insertions(+), 0 deletions(-)
diff --git a/parser.c b/parser.c
@@ -74,6 +74,9 @@ static struct object *evalset(struct object *);
 
 /* primitive procedures */
 static struct object *evalboolean(struct object *);
+static struct object *evalcar(struct object *);
+static struct object *evalcdr(struct object *);
+static struct object *evalcons(struct object *);
 static struct object *evaldiff(struct object *);
 static struct object *evaleq(struct object *);
 static struct object *evalgt(struct object *);
@@ -100,6 +103,9 @@ struct {
 	struct object *(*fn)(struct object *);
 } procs[] = {
 	{ .name = "boolean", .fn = evalboolean },
+	{ .name = "car",     .fn = evalcar     },
+	{ .name = "cdr",     .fn = evalcdr     },
+	{ .name = "cons",    .fn = evalcons    },
 	{ .name = "diff",    .fn = evaldiff    },
 	{ .name = "eq",      .fn = evaleq      },
 	{ .name = "gt",      .fn = evalgt      },
@@ -440,6 +446,59 @@ evalboolean(struct object *o)
 }
 
 static struct object *
+evalcar(struct object *o)
+{
+	struct object *arg;
+
+	if (o->type != OPair)
+		return NULL;
+	if (car(o)->type != OIdentifier ||
+	    strcmp(car(o)->d.i.name, "car") != 0)
+		return NULL;
+	if (caddr(o))
+		return error("multiple arguments");
+	arg = eval(cadr(o));
+	if (arg->type == OError)
+		return arg;
+	if (arg->type != OPair)
+		return error("expected pair");
+	return car(arg);
+}
+
+static struct object *
+evalcdr(struct object *o)
+{
+	struct object *arg;
+
+	if (o->type != OPair)
+		return NULL;
+	if (car(o)->type != OIdentifier ||
+	    strcmp(car(o)->d.i.name, "cdr") != 0)
+		return NULL;
+	if (caddr(o))
+		return error("multiple arguments");
+	arg = eval(cadr(o));
+	if (arg->type == OError)
+		return arg;
+	if (arg->type != OPair)
+		return error("expected pair");
+	return cdr(arg);
+}
+
+static struct object *
+evalcons(struct object *o)
+{
+	if (o->type != OPair)
+		return NULL;
+	if (car(o)->type != OIdentifier ||
+	    strcmp(car(o)->d.i.name, "cons") != 0)
+		return NULL;
+	if (cadddr(o))
+		return error("multiple arguments");
+	return cons(eval(cadr(o)), eval(caddr(o)));
+}
+
+static struct object *
 dodiff(struct object *o, struct object *n)
 {
 	struct object *arg;