Steven Schveighoffer wrote:
On Mon, 27 Jul 2009 18:37:01 -0400, Andrei Alexandrescu
... with zero arguments.
No, callable types period. Note that this does not compile:
class A
{
int delegate(int foo) wyda()
{
return delegate int(int foo) { return foo;};
}
}
int main(string[] args)
{
auto a = new A;
auto b = a.wyda(5); // line 14
auto c = a.wyda()(5);
return 1;
}
[ste...@steveslaptop files]$ dmd testme.d
testme.d(14): Error: function testme.A.wyda () does not match parameter
types (int)
testme.d(14): Error: expected 0 arguments, not 1
commenting out line 14 compiles.
Ok, thanks.
3. A getter can be defined in the opGet_X() form, and then using X()
will be the eqivalent of opGet_X()().
There are small implications to leaving the existing getter syntax.
Namely one can call a function not intended to be a getter in a
property-like syntax, resulting in less-than-obvious code.
This I don't agree with. I am very happy that I define popFront() as a
method and then call it without parens.
Knowing that you can call functions without parens, seeing code like:
r.popFront;
it's obvious that popFront is a function, not a property.
But, do you agree that this code looks less-than-obvious?
auto x = flush;
is flush a flag saying flushing should occur? is it a function that
flushes something, and returns the success? I agree that the bizarre
factor is not as bad as with setters, but it's still not as
self-explanatory as if you know that something without parens must be a
property for the compiler to accept it.
I think inferring meaning from the presence or absence of "()" is rather
dicey.
Let's separate this problem into two sections:
1. do we have to hint to the compiler that a function is a property or not?
I think we do, otherwise, we have the strange setter anomalies, and the
inability to return delegates from getters.
Well I don't think so. To repeat what I wrote elsethread: foo = bar is
rewritten into foo(bar) if and only if auto __x = foo, __x = bar works.
This means, a setter only works if there's a corresponding getter.
(Write-only properties be damned.)
Andrei
