Re: purge: opposite of grep

[Damian Conway]

Michael Lazzaro wrote:

If we're worried about the distance between the source and destination
when there are many tests

Are we? I'm not.

maybe:

    part { /foo/ => @foo, /bar/ => @bar, /zap/ => @zap }, @source;

Or, 'long' formatted:

    part {
        /foo/ => @foo,
        /bar/ => @bar,
        /zap/ => @zap,
    }, @source;

I really dislike the use of dative arguments (i.e. those that are modified
in-place by a function).

Besides, you can already write:

     push (
          /foo/ ?? @foo ::
          /bar/ ?? @bar ::
	  /baz/ ?? @baz ::
          []
     ), $_ for @source;

Heck, even in Perl 5 you can write:

     push @{
           /foo/ ? \@foo :
           /bar/ ? \@bar :
           /baz/ ? \@baz :
           []
     }, $_ for @source;

I keep thinking we're missing something here.  This is just a
multi-streamed C<grep>, after all.  It should be easy.

Famous last words. ;-)

Was it ever decided what C<for> would look like with multiple streams?

	for zip(@x, @y, @z) -> $x, $y, $z {...}

and its operator version:

	for @x ¦ @y ¦ @z -> $x, $y, $z {...}

Maybe we could just use the stream delimiters in the C<grep> like we do
in C<for>?

No. We gave up special stream delimiters in C<for>s,
in preference for general zippers.

Damian