[Newbies] Re: Re: error trap

[Damien Cassou]

> Yes. And, into the other direction, even in good core methods one often 
> finds things like
> 
>  ^ dict at: aKey ifAbsent: [nil]
> 
> There seems to be a "natural" confusion between "object" value and block 
> "value". 

What's the problem with that ? Yes, 'nil value' answers nil but 'nil' is 
not a block and #at:ifAbsent: waits for a block (the parameter is called 
aBlock). It is shorter to write 'nil' directly I agree.


What is more problematic in my point of view is code like this:

AbstractLauncher>>parameterAt: parName ifAbsent: aBlock
   "Return the parameter named parName.
     Evaluate the block if parameter does not exist."
   ^self parameters
     at: parName asUppercase
     ifAbsent: [aBlock value]



It may be me (still a beginner), but it looks equivalent to

   ^self parameters
     at: parName asUppercase
     ifAbsent: aBlock


which is faster and clearer in my opinion.