valueForUndefinedKey confusion

2010-02-15 Thread James Maxwell 
Hello All,

I have an NSMutableDictionary I'm trying to read from, but it's giving me 
valueForUndefinedKey errors. I can NSLog the key successfully, so I'm very 
confused as to what's going on.

NSLog(@Total number of components in work: %i, [AllComponents count]);
for(NSString* cKey in AllComponents)
{
NSLog(@key? %@, cKey);
MnSComponent *comp = (MnSComponent*)[AllComponents valueForKey:cKey];
[comp buildPitchMatrix];
[comp calculateTension];
}

The NSLog prints the expected key, then the code gags on the next line. ???


-

James B Maxwell
Composer/Doctoral Student
School for the Contemporary Arts (SCA)
School for Interactive Arts + Technology (SIAT)
Simon Fraser University
jbmaxw...@rubato-music.com
jbmax...@sfu.ca

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Re: valueForUndefinedKey confusion

2010-02-15 Thread Graham Cox 

On 16/02/2010, at 8:56 AM, James Maxwell wrote:

 I have an NSMutableDictionary I'm trying to read from, but it's giving me 
 valueForUndefinedKey errors. I can NSLog the key successfully, so I'm very 
 confused as to what's going on.
 
 NSLog(@Total number of components in work: %i, [AllComponents count]);
 for(NSString* cKey in AllComponents)
 {
   NSLog(@key? %@, cKey);
   MnSComponent *comp = (MnSComponent*)[AllComponents valueForKey:cKey];
   [comp buildPitchMatrix];
   [comp calculateTension];
 }
 
 The NSLog prints the expected key, then the code gags on the next line. ???

Try -objectForKey: instead of -valueForKey: there might be some subtlety of use 
KVC versus direct access that's screwing things up here. The key might contain 
characters that can be misinterpreted by KVC - containing '@' or '.' characters 
for example.

Also, are you certain that buildPitchMatrix and calculateTension are not 
mutating the dictionary? If they do the iteration will fail.

--Graham


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Re: valueForUndefinedKey confusion

2010-02-15 Thread James Maxwell 
Ha - that did it!
As expected, you are a rock star, Graham.

(and no, the following methods don't muck with the dictionary - it's obviously 
some subtlety in KVC... There is an underscore in the key string, so that 
probably borked it.)

cheers,

J.


On 2010-02-15, at 2:09 PM, Graham Cox wrote:

 
 On 16/02/2010, at 8:56 AM, James Maxwell wrote:
 
 I have an NSMutableDictionary I'm trying to read from, but it's giving me 
 valueForUndefinedKey errors. I can NSLog the key successfully, so I'm very 
 confused as to what's going on.
 
 NSLog(@Total number of components in work: %i, [AllComponents count]);
 for(NSString* cKey in AllComponents)
 {
  NSLog(@key? %@, cKey);
  MnSComponent *comp = (MnSComponent*)[AllComponents valueForKey:cKey];
  [comp buildPitchMatrix];
  [comp calculateTension];
 }
 
 The NSLog prints the expected key, then the code gags on the next line. ???
 
 Try -objectForKey: instead of -valueForKey: there might be some subtlety of 
 use KVC versus direct access that's screwing things up here. The key might 
 contain characters that can be misinterpreted by KVC - containing '@' or '.' 
 characters for example.
 
 Also, are you certain that buildPitchMatrix and calculateTension are not 
 mutating the dictionary? If they do the iteration will fail.
 
 --Graham
 
 

James B Maxwell
Composer/Doctoral Student
School for the Contemporary Arts (SCA)
School for Interactive Arts + Technology (SIAT)
Simon Fraser University
jbmaxw...@rubato-music.com
jbmax...@sfu.ca

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