m.invoke() vs. m()

[Reinier Zwitserloot]

Yes, I presumed Mark screwed up on that. The repercussions of being able to
invoke any variable of a closure type simply by tossing parentheses after
its mention are rather staggering. The closest you can get to something that
is backwards and migration compatible and doesn't completely change the
entire language is something like:

when the parser sees something of this form:

identifier(argslist[opt])

the parser will consider this a MethodCallOrClosureInvocation.

During resolution, if identifier refers to a method name that is in scope,
then this is a method invocation. If there is no such method name but there
is a variable with that name, then it is a closure invocation.

Meaning, if you create a new method, or one of your supertypes adds a new
method, or something is statically imported, then a closure invocation can
silently turn into a method invocation.

The fun quadruples when you try to add some rule to the tune of: if
'identifier' is a legal method but the argslist doesn't fit any of that
method's overloads, but it does fit the closure, then presumably, execute
the closure instead. Yich.

That's rather a lot of dancing the parser/resolver has to do in an area
that's already extremely complicated (method resolution), all to avoid
having to write '.invoke' in there. I'm not a fan of frivolous syntax merely
to highlight something that your IDE can already tell you (that 'identifier'
is a variable with a closure type), but in this case, the '.invoke' actually
does impart something of significance that your parser/IDE cannot always
infer for you: That the thing to the left of the invoke is a variable and
not a method name.

--Reinier Zwitserloot



On Sat, Dec 5, 2009 at 1:33 PM, <tronicek at fit.cvut.cz> wrote:

> Hi,
>
> I noticed a discussion about m.invoke() and m() on Mark Reinhold's blog
> and although it is true that if m is in the variable name space, we need
> "invoke", if syntax
>
> fun void m(int x);
>
> is adopted, it seems natural to have m in the method name space and then
> the "invoke" is not needed.
>
> Z.
> --
> Zdenek Tronicek
> FIT CTU in Prague
>
>
>
>
>
>
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