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POTouchJSON, dealing with NSNull
 

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    <p>Hi I am using TouchJSON to deserialize some JSON. I have been using it in the past and on those occasions I dealt with occurrences of NSNull manually. I would think the author had to deal with this as well, so me doing that again would just be overhead. I then found this in the documentation:</p> <blockquote> <p>Avoiding NSNull values in output.</p> </blockquote> <pre><code>NSData *theJSONData = /* some JSON data */ CJSONDeserializer *theDeserializer = [CJSONDeserializer deserializer]; theDeserializer.nullObject = NULL; NSError *theError = nil; id theObject = [theDeserializer deserialize:theJSONData error:&amp;theError];} </code></pre> <p>The way I understand it the user of the class can pass a C-style null pointer to the deserializer and when it encounters a NSNull it will insert the values (NULL) passed to it. So later on when I use the values I won't get NSNull, but NULL.</p> <p>This seems strange, the return value is an NSDictionary which can only contain Objects, shouldn't the value default to 'nil' instead?</p> <p><strong>If it is NULL can I check the values like this?</strong></p> <pre><code>if([jsonDataDict objectForKey:someKey] == NULL) </code></pre> <p>It would seem more logically to be able to do this:</p> <pre><code>if(![jsonDataDict objectForKey:someKey]) </code></pre> <p>No to mention all the cases where passing nil is allowed but passing NULL causes a crash.</p> <p><strong>Or can I just pass 'nil' to the deserializer?</strong></p> <p>Much of this stems from me still struggling with nil, NULL, [NSNULL null], maybe I am failing to see the potential caveats in using nil.</p>
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    1. COI commented below, but for the sake of posterity on this question, NSDictionary *cannot* contain nil as a key OR a value. From the Cocoa docs: "Neither a key nor a value can be nil; if you need to represent a null value in a dictionary, you should use NSNull."
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