Re: Syntactic sugar for function parameters

[Rici Lake <lua@...>]

On 5-Feb-07, at 2:07 AM, Ivan-Assen Ivanov wrote:

> > About empty (): without it, how would you make the difference between 
> > the
> > function itself ( e.g. to pass it as a parameter to a higher-order
> > function), and the application of that function?
>
> I'm not talking about the empty () at the end of a application without
> parameters, but the empty () after the function keyword when an
> function without parameters is defined:
>
> foobar = function() frob() end

If you could leave out the () in that, it would turn into:

foobar = function frob() end

but

function frob() end

is a statement defining the function frob.

That's not strictly speaking ambiguous, since a statement cannot follow 
the symbol '=', but it's very confusing.

Here's a real ambiguity, though. The following is a valid Lua statement:

(a)(b)

The () around the a are unnecessary in this case, but they are legal. 
So, now consider:

foobar = function (a) (b) (c) end

If you could leave out () after 'function', then that becomes 
ambiguous: is it a function of no arguments whose body is (a)(b)(c), or 
is it a function of one argument (a) whose body is (b)(c)