[m-dev.] @ syntax (was: Freeze the compiler)

[Ralph Becket]

>From Michael Day on 14/11/2000 08:07:27
> 
> > It would just be a syntactic transformation.
> > You would just declare e.g.
> > 
> > 	:- func elem(map(K, V), K) = V.
> > 	:- func 'elem :='(map(K, V), K, V) = map(K, V).
> 
> In the 'elem :=' example, must the space be preserved exactly? Will
> including an extra space or two produce obscure error messages?

I believe that the correct syntax is to have no spaces at all
before the `:=' (I would have voted for one, but I shan't quibble).

> > It seems a bit excessive to have _four_ different syntaxes for
> > accessing array elements:
> 
> So does this mean the @ syntax won't be included? Is it complicated (ie:
> will it take long) to add the extensions to the ^ syntax?

The @ syntax should not be included.

The original @ syntax would be nice for *just* lookup 
operations, but the concensus (of which I am now one) seems to be that
extending the `^' notation and completely forgetting `@' is the way
to go.  The syntax combining `^' and `@' is horrible.

--
Ralph Becket      |      MSR Cambridge      |      rbeck at microsoft.com 

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