From 5458d9ab8b91c0eacc012ad188fc0b63846adf3f Mon Sep 17 00:00:00 2001
From: Matthias Andreas Benkard <matthias@benkard.de>
Date: Sun, 27 Jul 2008 19:05:08 +0200
Subject: Add FUNCTION.

---
 MLKInterpreter.m | 28 ++++++++++++++++++++++++++++
 MLKPackage.m     |  1 +
 2 files changed, 29 insertions(+)

diff --git a/MLKInterpreter.m b/MLKInterpreter.m
index 46b8676..8237f7b 100644
--- a/MLKInterpreter.m
+++ b/MLKInterpreter.m
@@ -54,6 +54,7 @@ static MLKSymbol *LAMBDA;
 static MLKSymbol *LET;
 static MLKSymbol *APPLY;
 static MLKSymbol *FUNCALL;
+static MLKSymbol *FUNCTION;
 static MLKSymbol *EVAL;
 static MLKSymbol *QUOTE;
 static MLKSymbol *SETQ;
@@ -85,6 +86,8 @@ static MLKSymbol *_LAMBDA;
   LET = [cl intern:@"LET"];
   APPLY = [cl intern:@"APPLY"];
   EVAL = [cl intern:@"EVAL"];
+  FUNCALL = [cl intern:@"FUNCALL"];
+  FUNCTION = [cl intern:@"FUNCTION"];
   QUOTE = [cl intern:@"QUOTE"];
   SETQ = [cl intern:@"SETQ"];
   SETF = [cl intern:@"SETF"];
@@ -317,6 +320,31 @@ static MLKSymbol *_LAMBDA;
                            withEnvironment:[MLKLexicalEnvironment
                                              globalEnvironment]];
             }
+          else if (car == FUNCTION)
+            {
+              id functionName = [[program cdr] car];
+
+              if ([functionName isKindOfClass:[MLKCons class]]
+                  && ([functionName car] == LAMBDA
+                      || [functionName car] == _LAMBDA))
+                {
+                  return [self eval:functionName
+                               inLexicalContext:context
+                               withEnvironment:lexenv
+                               expandOnly:expandOnly];
+                }
+              else if (expandOnly)
+                {
+                  RETURN_VALUE (program);
+                }
+              else
+                {
+                  // FIXME: Function names need not be symbols.
+                  id <MLKFuncallable> function =
+                    [lexenv functionForSymbol:functionName];
+                  RETURN_VALUE (function);
+                }
+            }
           else if (car == IF)
             {
               id condition = [[program cdr] car];
diff --git a/MLKPackage.m b/MLKPackage.m
index 3d94d69..93dece3 100644
--- a/MLKPackage.m
+++ b/MLKPackage.m
@@ -73,6 +73,7 @@ static NSMutableDictionary *packages = nil;
   [cl export:[cl intern:@"LET"]];
   [cl export:[cl intern:@"LAMBDA"]];
   [cl export:[cl intern:@"FUNCALL"]];
+  [cl export:[cl intern:@"FUNCTION"]];
   [cl export:[cl intern:@"PROGN"]];
   [cl export:[cl intern:@"APPLY"]];
   [cl export:[cl intern:@"PROGV"]];
-- 
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