Make alias parameter optional?

[Jacob Carlborg]

On 2012-02-27 00:04, Ali Çehreli wrote:
> On 02/26/2012 03:45 AM, Jacob Carlborg wrote:
>  > On 2012-02-26 11:03, Ali Çehreli wrote:
>  >> On 02/25/2012 05:04 PM, Robert Rouse wrote:
>  >> > On Saturday, 25 February 2012 at 23:10:51 UTC, Ary Manzana wrote:
>  >> >> On 2/25/12 7:31 PM, Robert Rouse wrote:
>  >>
>  >> ...
>  >>
>  >> >>> This means that D can simulate Ruby blocks more than I thought.
>  >> That's
>  >> >>> pretty awesome. I'm loving D more every day.
>  >> >>
>  >> >> How's that like a Ruby block?
>  >> >
>  >> > The D code simulates the following Ruby if you were to make bar print
>  >> > "something" with writeln.
>  >> >
>  >> > def foo(a, b, &block)
>  >> > puts "a is #{a}")
>  >> > b.call
>  >> > yield
>  >> > end
>  >> >
>  >> > f = lambda { puts "good bye" }
>  >> >
>  >> > foo(1, f) { puts "something" }
>  >> >
>  >> >
>  >> > That's what I'm talking about.
>  >> >
>  >>
>  >> I don't know Ruby but from what I've read so far about Ruby blocks,
>  >> their D equivalents may also be D ranges.
>  >>
>  >> Ali
>  >
>  > A Ruby block is basically like a delegate in D and has nothing to do
>  > with ranges.
>  >
>  > Ruby:
>  >
>  > def foo (&block)
>  > block.call
>  > end
>  >
>  > foo do
>  > p "asd"
>  > end
>  >
>  > D:
>  >
>  > void foo (void delegate () block)
>  > {
>  > block();
>  > }
>  >
>  > void main ()
>  > {
>  > foo({
>  > writeln("asd");
>  > });
>  >
>  > foo(() => writeln("asd")); // new lambda syntax
>  > }
>  >
>  > Both examples print "asd". If you want to have a more Ruby looking
>  > syntax in D you do some operator overload abuse:
>  >
>  > struct Block
>  > {
>  > void delegate (void delegate ()) impl;
>  >
>  > void opIn (void delegate () block)
>  > {
>  > impl(block);
>  > }
>  > }
>  >
>  > Block foo ()
>  > {
>  > return Block((x) => x());
>  > }
>  >
>  > void main ()
>  > {
>  > foo in {
>  > writeln("asd");
>  > };
>  > }
>  >
>
> I see, thanks. The reason I thought about ranges is that the yield
> statement in the Ruby code above reminded me of Python's generators, and
> that D's ranges can also take the role of generators.
>
> Ali
>

"yield" in Ruby is just a way to call a block:

def foo
     yield
end

def bar (&block)
     block.call
end

The second example is a more explicit way of calling a block. Often 
blocks are used to iterate in Ruby:

[3, 4, 5].each do |e|
     # do something with e
end

-- 
/Jacob Carlborg