if-expressions

[Bent Rasmussen]

"David B. Held" <dheld at codelogicconsulting.com> wrote in message 
news:f3e2fn$2h7$1 at digitalmars.com...
>
> The advantage of having a statement-form of 'if' is that it creates a 
> scope (expressions never create a scope).  Also, if allows you declare a 
> variable in the condition, which is also not possible in expressions. See 
> if your other languages can do that. ;)

You mean something like this? :-)

public static function mapPartial<S,T>(f: S -> Option<T>, s: Stream<S>): 
Stream<T>
{
    return if (empty(s))
        znone
    else {
        var e = f(hd(s));
        if (Options.empty(e))
            mapPartial(f,tl(s))
        else
            some(Options.get(e),callback(mapPartial,f,tl(s)));
    }
}

No variable in the condition though.

But thinking about it some more, this would be a very disruptive change for 
existing D programs, so it would be better to just try and use ?:.

R.
Bent