Comments on: Series, Memoization, and Limits

By: colomon

colomon — Fri, 03 Sep 2010 20:11:38 +0000

I believe you are correct that this should work. But it definitely doesn’t in Rakudo at the moment.

Eevee — Fri, 03 Sep 2010 19:20:23 +0000

It seems intuitive to me that this should work:

my @fib := (0, 1, -> $a, $b { $a + $b } … *);
my @fib_capped := (@fib … 900);

But it appears not to be the case. I think the … operator is trying to eagerly consume @fib. Perhaps it should not?

Patrick Michaud — Fri, 03 Sep 2010 18:51:08 +0000

To stop a grep or map, use last:

  my @F-low := @Fibonacci.map( { last if $_ > 900; $_ } );
  say @F-low[10];
  say @F-low[20];  # no longer infinite