Re: Expression-local variables and 'let'

>>Agreed. Unfortunately, that's also why it does not seem right in the 
>>middle of an expression.
>>    
>>
>
>We can go around and around. 
>  
>
Seems so...

>Seems to me that we're optimizing for the (wild assed guess) 20% of
>user-defined statements, rather than ordinary assignments. 
>
Good point, expression-local variables are probably much less frequent. 
If we can make them nice without making the common case worse, it's all 
benefit, though.

>And I'd side
>with the Ada designers for readability over concision - readability
>helps me write correct code.
>  
>
I agree the readability is key. I'm not a perl fan... But I think 
readability and conciseness are not opposed in principle. In some cases 
they are, in some they come together.

I'd say that:

using(val in = ...) {
  ...
}

is more readable than

{
  let in = ...;
  using (in) {
    ..
  }
}

since the second form, because of the extra braces and line, obscures 
the purpose of the code.

>Cloneable and Serializable are not of our making, they are gifts from
>Java used as nouns. And they make some sort of sense, implementors of
>Cloneable are cloneable.
>
>IIRC 'alike' corresponds to the type in the same way that 'this'
>corresponds to the instance of that type - 'alike' is 'selftype' or
>'thistype'.
>  
>
Right. The term 'alike' is also commonly used for this concept, I did 
not invent it.

>I understand Brian's discomfort with 'alike'.
>OTOH we say that these are multimethods and there is no privileged
>method receiver; OTOH we don't have a way to express 'alike' when the
>method is outside a class. 
>  
>
You can, and for any parameter, using a constrained type parameter:

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.

Daniel



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