This new warning adds a lot of warnings in the Cappuccino frameworks. I have turned off
the warning in the Jakefiles when compiling most of the Cappuccino frameworks. But it is
on as default for any user projects.
So there is also a new feature to turn off/on warnings as a compiler flag.
These flags are (all flags are on as default):
-Wunused-but-set-variable Warning when a local variable is never read.
-Wshadow-ivar Warning when a local variable is shadowing an instance variable for the class.
-Wcreate-global-inside-function-or-method Warning when creating a global variable inside a function or method.
-Wunknown-class-or-global Warning when a class or global variable is not known.
-Wunknown-ivar-type Warning when the type for an instance variable is not known.
To turn off a flag add a 'no-' prefix. Example: -Wno-unused-but-set-variable
For an example how to use it in a Jakefile please look at the Jakefiles in this commit.
An example:
var array = @[ @{@"Name": @"1"},
@{@"Name": @"2", @"approveTime": @"Now"}
];
var predicate = [CPPredicate predicateWithFormat:@"approveTime != nil"];
CPLog(@"result: %@", [array filteredArrayUsingPredicate:predicate]); // result: <empty array>
If I run this in Cappuccino I get an empty array
If I run it in Cocoa on a Mac I get:
result: (
{
Name = 2;
approveTime = Now;
}
This prevents a buildup of large arrays with a lot of values and then choose one row and throw away the rest. This is great for speed and a must for lazy loading.
Previous there was a optimization for this but it was only effective for short combined key path like 'a.b'. This pull request makes it effective for any kind of length of a combined key path like 'a.b.c.d...'.
This is done by returning the object at a row in the first found CPArray in the key path
that is divided in a first and second part.
The first part is never a combined key path. The second part can be a combined key path.
If this optimization is not done we will create an array with the valueForKeyPath value on each row and then pick
the wanted value for the row and throw away all the other rows. It is much more effective to first
pick the row and then do the valueForKeyPath on the rest of the key path.
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;
...
To mimic Objective-C correctly the +initialize method should not be sent on a class hierarchy if it does not implement it.
Also the +initialize method should not allowed to be forwarded to another target with Invocation or any other forwarding mechanism.
Added test cases for this and cleaned up some test cases that succeeded for the wrong reason.
This change will not affect many projects as all classes inherit from CPObject.
daboe01
cacaodev
Martin Carlberg
Didier KorthoudtandGitHub
cacaodevandGitHub
jasperdebandMartin Carlberg
Alexander Ljungberg
Didier KorthoudtandMartin Carlberg