Changeset 1762

Timestamp:

11/12/08 06:03:30 (8 weeks ago)

Author:

Chuck.Esterbrook

Message:

Better error messages for C# syntax += and -= applied to events and delegates.

Location:

cobra/trunk

Files:

• Developer/IntermediateReleaseNotes.text (modified) (1 diff)
• Source/BinaryOpExpr.cobra (modified) (1 diff)
• Source/Compiler.cobra (modified) (1 diff)
• Tests/220-delegates-etc/120-events/400-augmented-assignment-error.cobra (added)

cobra/trunk/Developer/IntermediateReleaseNotes.text

@@ -145 +145 @@
 For convenience, the extension methods .toPrintString and .toTechString have been added to System.Object.
 
-* Added improved error checking and/or error messages for `throw`, `raise` and `use`.
+* Added improved error checking and/or error messages for `throw`, `raise` and `use`. Also, better error messages for C# syntax += and -= applied to events and delegates.
 
 * Added various library methods from .NET to the primitive types such as decimal, int, char, bool, etc. These are documented on @link(http://cobra-language.com/trac/cobra/wiki/PrimitiveTypeMembers, the wiki). These include mathematical methods so you can say `x.round`, `x.round(decimals)`, `a.min(b)`, `x.sin`, `x.truncate`, etc.

cobra/trunk/Source/BinaryOpExpr.cobra

@@ -392 +392 @@
                 base._bindImp
                 # TODO: does NumericPromoExpr cover everything we need?
+                # C# and other languages use += and -= on delegates and events, but Cobra does not.
+                if .left.type inherits MethodSig
+                        # TODO: error
+                        pass
+                else if .left.type.isDescendantOf(.compiler.delegateType)
+                        # TODO: distinguish between events and delegates
+                        leftSource = .left.toCobraSource
+                        rightSource = .right.toCobraSource
+                        if not .right inherits RefExpr, rightSource = 'ref ' + rightSource
+                        branch .op
+                                on 'PLUS_EQUALS',  .throwError('Cannot use "+=". Use "listen [leftSource], [rightSource]" for events and "[leftSource] = Delegate.combine([leftSource], [rightSource])" for delegates.')
+                                on 'MINUS_EQUALS', .throwError('Cannot use "-=". Use "ignore [leftSource], [rightSource]" for events and "[leftSource] = Delegate.remove([rightSource])" for delegates.')
+                                else, .throwError('Cannot use the operator "[.token.text]" on events or delegates.')
 
 

cobra/trunk/Source/Compiler.cobra

@@ -1178 +1178 @@
                 return _libraryClass('System.Exception')
 
+        def delegateType as Class
+                return _libraryClass('System.Delegate')
+
         def attributeType as Box
                 return _libraryBox('System.Attribute')