Make it possible to assign a place that doesn't exist, and then have …

…it disappear again. This allows temporary overriding in the manner of categories, for specific cells
olabini · Jan 10, 2009 · 8af3954 · 8af3954
1 parent e294578
commit 8af3954
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Showing 3 changed files with 41 additions and 4 deletions.
diff --git a/src/main/ioke/lang/FlowControlBehavior.java b/src/main/ioke/lang/FlowControlBehavior.java
@@ -68,7 +68,12 @@ public Object activate(IokeObject method, IokeObject context, IokeObject message
                                     wherePlace = Message.getEvaluatedArgument(place, context);
                                 }
 
-                                Object originalValue = realPlace.sendTo(context, wherePlace);
+                                Object originalValue = null;
+                                try {
+                                    originalValue = realPlace.sendTo(context, wherePlace);
+                                } catch(Throwable e) {
+                                    originalValue = null;
+                                }
 
                                 if(realPlace.getArguments().size() != 0) {
                                     String newName = realPlace.getName() + "=";
@@ -96,10 +101,24 @@ public Object activate(IokeObject method, IokeObject context, IokeObject message
                                 if(realPlace.getArguments().size() != 0) {
                                     String newName = realPlace.getName() + "=";
                                     List<Object> arguments = new ArrayList<Object>(realPlace.getArguments());
-                                    arguments.add(context.runtime.createMessage(Message.wrap(IokeObject.as(value))));
-                                    context.runtime.newMessageFrom(realPlace, newName, arguments).sendTo(context, wherePlace);
+
+                                    if(value == null) {
+                                        if(newName.equals("cell=")) {
+                                            context.runtime.removeCellMessage.sendTo(context, wherePlace, new ArrayList<Object>(realPlace.getArguments()));
+                                        } else {
+                                            arguments.add(context.runtime.createMessage(Message.wrap(context.runtime.nil)));
+                                            context.runtime.newMessageFrom(realPlace, newName, arguments).sendTo(context, wherePlace);
+                                        }
+                                    } else {
+                                        arguments.add(context.runtime.createMessage(Message.wrap(IokeObject.as(value))));
+                                        context.runtime.newMessageFrom(realPlace, newName, arguments).sendTo(context, wherePlace);
+                                    }
                                 } else {
-                                    IokeObject.assign(wherePlace, realPlace.getName(), value, context, message);
+                                    if(value == null) {
+                                        IokeObject.removeCell(wherePlace, context, message, realPlace.getName());
+                                    } else {
+                                        IokeObject.assign(wherePlace, realPlace.getName(), value, context, message);
+                                    }
                                 }
                             } catch(Throwable e) {}
                         }

diff --git a/src/main/ioke/lang/Runtime.java b/src/main/ioke/lang/Runtime.java
@@ -117,6 +117,8 @@ public class Runtime {
     public IokeObject inspectMessage = newMessage("inspect");
     public IokeObject noticeMessage = newMessage("notice");
 
+    public IokeObject removeCellMessage = newMessage("removeCell!");
+
     public IokeObject plusMessage = newMessage("+");
     public IokeObject minusMessage = newMessage("-");
     public IokeObject multMessage = newMessage("*");

diff --git a/test/let_spec.ik b/test/let_spec.ik
@@ -52,6 +52,22 @@ describe(DefaultBehavior,
             error!("non-local yay!")))
         Text fluxie2 wowsie should == 13
       )
+
+      it("should bind a new place temporarily, and then remove it",
+        X = Origin mimic
+        let(X testOfLetMethod, method(42),
+          X testOfLetMethod should == 42
+        )
+        X cellNames should not include(:testOfLetMethod)
+      )
+
+      it("should bind a new place with cell temporarily, and then remove it",
+        X = Origin mimic
+        let(X cell(:testOfLetMethod2), method(42),
+          X testOfLetMethod2 should == 42
+        )
+        X cellNames should not include(:testOfLetMethod2)
+      )
     )
   )
 )