On 2014-01-07 21:44, H. S. Teoh wrote:
If you have a good motivating use case in favor of this addition that
can be used in a DIP, I'd vote for it.
I'm usually not good at these arguments. I mean, it would be nice to
have but I don't have any strong arguments for it. It's just syntax sugar.
I like the alias idea, so here's the revised proposal:
1) Argumentless trailing-delegate syntax:
// Given this declaration:
void foo(alias dg)();
// We can write this:
foo {
// body
}
// which will get translated into:
foo!({ /* body */ });
2) With arguments:
// Given this declaration:
void foo(alias dg, A...)(A args);
// Or its non-template equivalent:
void foo(alias dg)(A arg1, B arg2, C arg3, ...);
// We can write this:
foo(a,b,c,...) {
// body
}
// which gets translated into:
foo!({ /* body */})(a,b,c,...);
3) With indexing arguments:
// Given this declaration:
void foo(alias dg, I..., A...)(A args)
if (is(typeof(dg(I))));
// Or its non-template equivalent:
void foo(alias dg)(A arg1, B arg2, C arg3, ...) {
...
dg(i, j, k);
...
}
// We can write this:
foo(i,j,k,... ; a,b,c,...) {
// body
}
I would prefer to have the delegate arguments last.
// which gets translated into:
foo!((i,j,k,...) { /* body */ })(a,b,c,...);
EXAMPLE:
void for_every_other(alias loopBody, R)(R range)
if (is(typeof(loopBody(ElementType!R.init))))
{
while (!range.empty) {
loopBody(range.front);
range.popFront();
if (!range.empty)
range.popFront();
}
}
// Prints:
// ---
// 1
// 3
// 5
// ---
for_every_other (i; [1,2,3,4,5,6]) {
writeln(i);
}
If we instead have the delegate argument last UFCS still works:
[1,2,3,4,5,6].for_every_other(i) {
writeln(i);
}
Hmm. Actually, your example is more D like. I don't know which I example
I like best.
I'll see if I can write something down.
--
/Jacob Carlborg
