Dear Brethren,

Let us imagine for a moment that we wished to find the number of even numbers in the range 1 .. 1_000_000_000, then following code should work...

my $n = grep { $_ % 2 == 0 } (1 .. 1_000_000_000);

However my machine reflects upon this and responds thusly:

panic: realloc at ./inf line 6.

While perl is correctly lazy in it's evaluation of a ranage, it get very industrious when you wish to pass it to grep, map and friends.

While there are a number of CPAN modules that work around this with there own lazy versions of map and grep, does anyone know why perl's own functions have never been changed to the appropriately slothful?

NB: The question is not how, that is trivial. The question is why is perl still the way it is?

--
Fools ignore complexity. Pragmatists suffer it.
Some can avoid it. Geniuses remove it.

In reply to Making perl's map and grep more large list friendly by nudge

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