[Swift-devel] Re: How to wait on functions that return no data?

[Mihael Hategan]

On Tue, 2008-03-25 at 22:49 +0000, Ben Clifford wrote:
> On Tue, 25 Mar 2008, Michael Wilde wrote:
> 
> > Related to this virtual idea, is it possible to add language semantics where a
> > function defined as returning an object can decide to return "null", in which
> > case its deemed to be complete but decided no to generate a result?
> 
> Going to haskell way, introducing a Maybe type would be that - its a 
> dataflow rather than control flow form of exception handling. You declare 
> a type as 'maybe resultfile' and values of that type can be either 
> 'Nothing' or a result file.
> 
> You could have an array of:
> 
> (Maybe resultfile)[]
> 
> where each element is of type 'maybe resultfile' and so can (independent 
> of the other elements) be a file or null.

pretty much like try {a[x] = f(x)} catch {} or maybe(a[x] = f(x)).

>