> -----Original Message----- > From: Luke Palmer [mailto:[EMAIL PROTECTED] > Sent: Tuesday, November 18, 2003 10:49 AM > To: Austin Hastings > Cc: Language List > Subject: Re: Control flow variables > > > Austin Hastings writes: > > Luke Palmer wrote: > > > I was reading the most recent article on perl.com, and a code segment > > > reminded me of something I see rather often in code that I don't like. > > > Here's the code, Perl6ized: > > > > > > ... ; > > > my $is_ok = 1; > > > for 0..6 -> $t { > > > if abs(@new[$t] - @new[$t+1]) > 3 { > > > $is_ok = 0; > > > last; > > > } > > > } > > > if $is_ok { > > > push @moves: [$i, $j]; > > > } > > > ... > > > > This is what I was talking about when I mentioned being able to do: > > > > &cleanup .= { push @moves: [$i, $j]; } > > > > a few weeks ago. Treat code vars like code, not like sub-refs. > > I'm not sure I know what you mean with regard to this example. > Exemplify further, please? >
Quoting Luke Palmer from weeks back: > From: Luke Palmer [mailto:[EMAIL PROTECTED] > Jeff Clites writes: > > Austin Hastings writes: > > > Speaking to the practical side, I have written code that has to > > > disentangle itself from the failure of a complex startup sequence. > > > I'd love to be able to build a dynamic exit sequence. (In fact, > > > being able to do <C>&block .= { more_stuff(); };</C> is way up > > > on my list...) > > > > I've wanted to do that sort of thing before, but it seems simpler > > (conceptually and practically) to build up an array of cleanup > > subs/blocks to execute in sequence, rather than to have a .= for > > blocks. (Another reason it's handy to keep them separate is in cases in > > which each needs to return some information--maybe a status which > > determines whether to proceed, etc.) > > But this is already supported, in its most powerful form: > > wrap &block: { call; other_stuff() } > > Luke Which begs the question of whether there's a way to get a handle to the current <C>for</C> loop from within? LOOP: for 0..6 -> $t { if abs(@new[$t] - @new[$t+1]) > 3 { wrap &Block(): { call; handle_error(); }; last; } } # handle_error() called here? (Yes, this would presume that the <C>call</C> came first, since how could it interpolate the call otherwise. It's a limitation of the wrap-as-append philosophy.) =Austin
