Add MLKPrintToString along with a couple of fixnum handling functions.

1 files changed, 66 insertions, 0 deletions

diff --git a/functions.m b/functions.m
new file mode 100644
index 0000000..136c2da
--- /dev/null
+++ b/functions.m
@@ -0,0 +1,66 @@
+/* -*- 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 "functions.h"
+#import "MLKInteger.h"
+
+NSString *MLKPrintToString (id object)
+{
+  if (object == nil)
+    return @"()";
+  else if (MLKInstanceP (object))
+    return [object descriptionForLisp];
+  else if (MLKFixnumP (object))
+    return MLKPrintToString ([MLKInteger
+                               integerWithInt:(MLKIntWithFixnum (object))]);
+  else
+    {
+      NSLog (@"MLKPrintToString: Encountered a really weird object at address %p",
+             object);
+      return @"<??\?>";
+    }
+}
+
+intptr_t MLKIntWithFixnum (id fixnum)
+{
+  return ((intptr_t)fixnum >> 1);
+}
+
+id MLKFixnumWithInt (intptr_t value)
+{
+  return (id)((value << 1) | 1);
+}
+
+id MLKIntegerWithInt (intptr_t value)
+{
+  intptr_t maybeFixnum = ((intptr_t)value << 1) | 1;
+  if (value == (maybeFixnum >> 1))
+    return (id)maybeFixnum;
+  else
+    return [MLKInteger integerWithInt:value];
+}
+ 
+BOOL MLKFixnumP (id thing)
+{
+  return ((intptr_t)thing & 1);
+}
+
+BOOL MLKInstanceP (id thing)
+{
+  return !((intptr_t)thing & 1);
+}