[Pharo-dev] [squeak-dev] last block arg as implicit return value?

Eliot Miranda eliot.miranda at gmail.com
Mon May 12 13:17:31 EDT 2014


On Mon, May 12, 2014 at 10:05 AM, Nicolas Cellier <
nicolas.cellier.aka.nice at gmail.com> wrote:

> I think I remember it was either the first or last parameter that was
> returned in old implementation
>

the last. ([:a :b|] value: #first value: #last) == #last


>
> It's a known problem: http://bugs.squeak.org/view.php?id=5793
>
> but I would have thought that this was fixed with Eliot's closure...
>

I kept the old semantics, trying to rock the boat as little as possible.  I
just checked the draft standard.  The end of 3.4.4 "blocks" reads

"If a block has no <block body> or no <statements> in its <block body> then
the value of the block is undefined."
I've found the returning the last value bizarre for a while.  If others
feel strongly we could fix it for 4.6/5.0.  But I'd want agreement with
Pharo.  Marcus what does Opal do with:

    [:a :b|] value: #first value: #last

?

Squeak & VW answer #last.


>
>
> 2014-05-12 17:58 GMT+02:00 blake <dsblakewatson at gmail.com>:
>
> >> | myBlock |
>> >> myBlock := [ : arg1 : arg2 | ].
>> >> myBlock value: 'hello' value: 'there'
>>
>> nil
>>
>> Because the block isn't returning a value and the last line is calling
>> the block.
>>
>>
>>
>>
>
>
>
>


-- 
best,
Eliot
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