The msgSend function has always returned nil if the receiver has been nil or undefined.
Example:
var a = undefined;
var b = [a someSelector]; // b = nil
The variable b is now nil.
This pull request adds the ability for the msgSend function to return undefined if the receiver is undefined. If the receiver is nil it still return nil.
The above example again:
var a = undefined;
var b = [a someSelector]; // b = undefined
The variable b is now undefined.
Background.
The use of nil in Objective-C corresponds to the use of null in C and C++ and stands for "no value". A fundamental function in Objective-C is when you send a message to a receiver that is nil the result is again a nil value. This can be very convenient as you don't need the check if a receiver is nil before sending a message to it.
Objective-J adds the ability the use class structures and message send functionality for Javascript in the same way as Objective-C adds this to C and C++. Javascript also has the value null and is handled in the same way for Objective-J. Javascript also has the value undefined that stands for "not yet defined". This can sometimes be confusing and many try to handle null and undefined as the same thing. This is almost what Objective-J and the Cappuccino frameworks always has been doing. They try to always check for both null and ``undefined and always return nil but never undefined. We can say that Objective-J understands undefined but will try to translate it to nil.
Why do we need this change.
Javascript has both null and undefined and Objective-J is a superset of Javascript. It is now very hard to use undefined in Objective-J code as it will always try to translate it to nil. There are some Javascript libraries that use both null and undefined values and they are very hard to use from Objective-J programs today. Same if you decide to use nil and undefined as a value in your own Objective-J code. This small change will make undefined a full member of the Objective-J language. It should be as it is a superset of Javascript. The Cappuccino frameworks will still handle undefined but only return nil.
How will it impact.
Today most methods will never return undefined so this is a very limited problem. If any does this the main concern is if some code will only check for nil and not undefined.
Example:
var a = [someObject someSelector];
If (a === nil) a = 42;
...
If the variable someObject contains undefined the variable a will now be set to undefined instead of nil. But the variable a will then never be set to 42.
The correct way is to check for both nil and undefined like this:
var a = [someObject someSelector];
If (a == nil) a = 42;
...
Method browser:imageValueForItem was defined twice in CPBrowserDelegate. Once on line 43, and the other on line 45. This removes the commit removed the second declaration
CPTableView has no focus ring, and currently gives no visual feedback of its firstResponder status. In Cocoa when the table view resigns firstResponder or its window loses key status, the selection color turns gray.
This commit sets the selection color to gray when a table view resign firstResponder or its window loses key status. A second window and a couple of textfields were added to the CPDictionaryControllerTest to demonstrate the changes.
Fixes#1839
- Changed from deprecated image scaling constants to new ones.
- Added support for CPImageScaleProportionallyUpOrDown (thanks BlairDuncan).
- Cleaned up image layout code.
All classes (excluding the ones prefixed with underscores) in Foundation
and AppKit can now be loaded individually except CPOpenPanel and
CPSavePanel. These two classes have some sort of dependency cycle
that seems impossible to resolve without forward declarations (which
we don't have).
Martin Carlberg
daboe01
daniel
Alexandre Wilhelm
Saikat Chakrabarti
Aparajita Fishman
Blair DuncanandAparajita Fishman
Alexander Ljungberg
Aparajita Fishman
Antoine Mercadal
James Dessart
Ross Boucher
Alexander Ljungberg
Paul Baumgart
Francisco Ryan Tolmasky I
Randall Luecke