[Types-sig] type declaration syntax

[skaller]

Paul wrote:

>Martijn Faassen wrote:
>> 
>> * we don't have to debate about syntax anymore and can actually think
>> about semantics without syntax confusion.
>
>Clean syntax helps comprehension. 

I don't agree, but this time it is because I think you have
_understated_ the issue. I think that the syntax is just
about the ONLY issue here: what 'semantics' is there to debate?

The way I see it, we need a way to declare something is type T, 
which is a syntax issue. And then we can argue about
waht "T" can be, which is, more or less, also a syntax issue.

Now, if we debate this, we will find we're getting into the
details of the type model, which is not a syntactic issue,
but it, well, is 'rendered' in syntax all the same.
For example, Viper is using a particular type model which is 
minor extension of CPython 1.5's own model, which leads
to a particular syntax: a python expression denoting an object
is what "T" is, rather than some new, invented, syntax
(like Tim Peters ML/Haskell like one).

In other words, I think we SHOULD focus on the syntax,
because it is the representation of the ideas we have,
and the one programmers will be using.

-- 
John Skaller, mailto:skaller@maxtal.com.au
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