[Openmcl-devel] Snow Leopard snafu

[R. Matthew Emerson]

On Sep 1, 2009, at 12:20 PM, Ron Garret wrote:

> OK, I get that I'm being a moron and I'm missing something obvious.
> But my house nearly burned down three days ago so I'm not really
> firing on all cylinders at the moment and would appreciate it if you
> could cut me a little slack here.  What is «the "with" component»?

As you know, an Objective-C instance is allocated and initialized with  
code like:

id something = [[MyObject alloc] init];

Often, a class typically has a number of initializers.  For example,  
from NSString.h we see something like:

- (id)init;
- (id)initWithCharacters:(const unichar *)characters length: 
(NSUInteger)length;
- (id)initWithUTF8String:(const char *)nullTerminatedCString;
- (id)initWithString:(NSString *)aString;
etc.

So we'd say

id something = [[NString alloc] initWithString:@"foo"];

To make this message sending look more lispy, we basically turn  
messages into generic functions.  Thus, the above would be:

(defvar *something* (#/initWithString: (#/alloc ns:ns-string) #@"foo"))

Fine.  Now, we try to make Objective-C more CLOS-like.  You can say:

(make-instance 'ns:ns-string :init-with-string #@"foo")

The #/alloc message is implicit (you still have to manually release  
the object). As another convenience, the "init-" part of the keyword  
argument can optionally be omitted:

(make-instance 'ns:ns-string :with-string #@"foo")

This may be a little too cute for its own good, but there it is.

(It's also potentially confusing, because Cocoa programmers are told  
something like "you own an object if you got it via calling some  
method that has "init" or "copy" in the name."  This abbreviated  
initarg convention conceals that.)

Anyway, after writing all this, I noticed the following change:

http://trac.clozure.com/openmcl/changeset/12652

This removes the unadorned ":string" initarg (among other changes), so  
you were right after all:  your code used to work, but this change  
broke it.

>> On Tue, 1 Sep 2009, Ron Garret wrote:
>>
>>> I upgraded to Snow Leopard, and now this happens:
>>>
>>> ? (make-instance gui::ns-lisp-string :string (coerce "foo" 'simple-
>>> base-string))
>>>> Error: Unknown ObjC init message: "initString:"