Bert Freudenberg wrote
>> On 29.05.2016, at 10:59, marcel.taeumel <

> Marcel.Taeumel@

> > wrote:
>> 
>> marcel.taeumel wrote
>>> Hi, there!
>>> 
>>> I cannot write this without the parser complaining:
>>> 
>>> number caseOf: {
>>>   0 -> 1.
>>>   1 -> 1.
>>> } otherwise: { ... }.
>>> 
>>> Because what I should write is this:
>>> 
>>> number caseOf: {
>>>  [0] -> [1].
>>>  [1] -> [1].
>>> } otherwise: { ... }.
>>> 
>>> I think that this is not for the parser to decide. Numbers do understand
>>> #value.
> 
> Only since recently. Still not sure it’s a good idea.
> 
>>> Any object does. So this is fine. Am I missing something?
>>> 
>>> It reminds me of this mistake our students typically make at least once:
>>> 
>>> (someBooleanExpression) and: (someOtherBooleanExpression)
>>> versus
>>> (someBooleanExpression) and: [someOtherBooleanExpression]
>>> versus
>>> [someBooleanExpression] and: (someOtherBooleanExpression)
>>> versus
>>> [someBooleanExpression] and: [someOtherBooleanExpression]
>>> 
>>> Sure, we can offer tool support to help in such situations. But the
>>> parser
>>> is just too naggy. :-)
>>> 
>>> Best,
>>> Marcel
>> 
>> Okay, this was stoopid. ;o) I assumed an implicit comparison:
>> 
>> number caseOf: {
>>  [number = 0] -> [1].
>>  [number = 1] -> [1].
>> } otherwise: { ... }. 
>> 
>> Still, no need to force the result also into a block? Why not just modify
>> the implementation of #caseOf:otherwise: to make such comparisons if
>> there
>> is no block given?
> 
> This is exactly the reason we resisted adding Object>>value for a long
> time, because it hides errors. E.g. your use of {} in the otherwise-case,
> which is wrong. Each case should be evaluated only when the matching
> condition is true, hence the need to use a block. Arguably the compiler
> should warn about not using a block as argument to ‘otherwise:'.
> 
> Perhaps a more Smalltalky way could be added if allowed binary and unary
> messages to cascade:
> 
>  number	= 0 => [24];
> 	= 1 => [42];
> 	else =>  ['hi']
> 
> Btw this is how things worked in Smalltalk-76/78:
> 
> 
> 
> 
> - Bert -
> 
> 
> 
> 
> 
> 
> 
> Screenshot 2016-05-30 12.48.12.png (4K)
> <http://forum.world.st/attachment/4898099/0/Screenshot%202016-05-30%2012.48.12.png>
> smime.p7s (5K)
> <http://forum.world.st/attachment/4898099/1/smime.p7s>

Hi Bert,

the debugger revealed my "otherwise: { ... }" mistake pretty quickly.

Thanks for the Smalltalk-72 example.

Best,
Marcel



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