Re: Expression-local variables and 'let'

Isaac Gouy wrote:

>>using(val in = ...) {
>>  ...
>>}
>>is more readable than
>>{
>>  let in = ...;
>>  using (in) {
>>    ..
>>  }
>>}
>>    
>>
>
>Maybe 
>   using(in = ...){} 
>is more readable still, 
>
That's already valid, if 'in' is already declared higher. So if you 
allow that for undeclared variables, that creates an ambiguity.

>like
>   for (i: 1..10){}
>  
>
Yes, but that's also problematic. In that case it's feasible, because 
for(_ : _) is special syntax. I still don't like it because it's 
inconsistent with the rest of the syntax.

using(in = ...) { ... } is pure user code, without any special handling, 
so allowing 'in' not to be declared would mean changing the whole 
language. That does not seam reasonable.

>>class Bar { ...}
>><Bar Alike> Alike foo(int x, Alike bar) { ... }
>>
>>The thing is that for methods declared inside a class, there is no
>>way to constrain the type of this, so 'alike' was needed.
>>    
>>
>
>So that in that example there's nothing special about 'Alike' - it's
>just a type parameter?
>   <Bar B> B foo(int x, B bar) { ... }
>  
>
Yes,

>So 'alike' is a fix for the "within a class" syntax sugar?
>  
>
Yes.

Daniel



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