[MacRuby-devel] new Hash class

Laurent Sansonetti lsansonetti at apple.com
Wed Mar 19 16:42:38 PDT 2008

On Mar 19, 2008, at 3:36 PM, Benjamin Stiglitz wrote:

>>> Also, Ben and I have been brainstorming on Monday about future
>>> changes, and here is what we decided:
>>> http://trac.macosforge.org/projects/ruby/wiki/MacRubyBrainstorming
>> These seem to all be Hash class related. Is there something which  
>> encompasses more of the big-picture brainstorming for MacRuby as a  
>> whole?
> There are a few other high-level directions in there, regarding  
> Number, Symbol, Nil/False/TrueClass, and Object. Laurent, I guess  
> you need to dump the rest of your brain there, though…

In fact these are already part of the braindump I think :) But it's  
not relatively intuitive I admit.

 > Hash primitives should rb_funcall if the receiver is a subclass of  

So that you can subclass Hash, override #[], and CFDictionary/ 
NSDictionary APIs should call your own implementation instead.

(Same for Array and String.)

 > Freezing an object should store a flag that should be checked in  
the primitive methods and appropriately raise an exception.

So that when Objective-C tries to modify a Hash that was frozen in  
Ruby, an exception would be raised in the Objective-C side.

(Same for Array and String.)

 > Symbols should be objects (flagged String) as they are actually  
represented in parse.y, and passed as they are in Objective-C.  
Incoming symbol objects should be recognized by the flag.

Currently in the core, symbols are pointer-like types and not real  
objects. The idea is to use a real object class instead (based on  
String), so that it can be passed to Objective-C without conversion.

 > All Ruby integers should be NSNumbers. Bignum is a custom subclass  
of NSNumber which implements the primitive methods. MacRuby should  
unique most numbers.

As symbols, fixnums in the core are not real objects but pointer-like  
types. The idea is to use CFNumbers instead and unique most of them  
(if not all?). Float and Bignum would be subclasses of CFNumber too,  
and incoming pure CFNumbers would be appropriately identified as Float  
by looking at the type.

 > Should we change the way Qtrue/Qfalse/Qnil are represented?

That's a pending issue. Qtrue, Qfalse and Qnil in the core are magic  
constants (respectively 2, 0 and 3). We cannot simply pass them to  
Objective-C as objects.


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