Add class MLKBinding.

1 files changed, 85 insertions, 0 deletions

diff --git a/MLKBinding.m b/MLKBinding.m
new file mode 100644
index 0000000..b3e2826
--- /dev/null
+++ b/MLKBinding.m
@@ -0,0 +1,85 @@
+/* -*- mode: objc; coding: utf-8 -*- */
+/* Étoilisp/Mulklisp, a Common Lisp subset for the Étoilé runtime.
+ * Copyright (C) 2008  Matthias Andreas Benkard.
+ *
+ * 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 3 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#import "MLKBinding.h"
+#import "runtime-compatibility.h"
+
+#import <Foundation/NSException.h>
+
+
+static id UNBOUND;
+
+
+@implementation MLKBinding
++(void) initialize
+{
+  UNBOUND = [[NSObject alloc] init];
+}
+
+-(MLKBinding *) init
+{
+  return [self initWithValue:UNBOUND];
+}
+
+-(MLKBinding *) initWithValue:(id)something
+{
+  self = [super init];
+  ASSIGN (value, something);
+  return self;
+}
+
++(MLKBinding *) binding
+{
+  return AUTORELEASE ([[self alloc] init]);
+}
+
++(MLKBinding *) bindingWithValue:(id)something
+{
+  return AUTORELEASE ([[self alloc] initWithValue:something]);
+}
+
+-(void) setValue:(id)something
+{
+  ASSIGN (value, something);
+}
+
+-(id) value
+{
+  if (value == UNBOUND)
+    [NSException raise:@"MLKUnboundVariableError"
+                 format:@""];
+
+  return value;
+}
+
+-(BOOL) boundp
+{
+  return !(value == UNBOUND);
+}
+
+-(void) makunbound
+{
+  ASSIGN (value, UNBOUND);
+}
+
+-(void) dealloc
+{
+  RELEASE (value);
+  [super dealloc];
+}
+@end