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Postings from October 2005
lrpalmer@gmail.com wrote:
>And that was never quite resolved. The biggest itch was with
>operators that have no identity, and operators whose codomain is not
>the same as the domain (like <, which takes numbers but returns
>bools).
>
>Anyway, that syntax was
>
> $sum = [+] @items;
>
>And the more general form was:
>
> $sum = reduce { $^a + $^b } @items;
>
>Yes, it is called reduce, because "foldl" is a miserable name.
>
>
>
To pick some nits, reduce and fold are different concepts. By
definition, reduce doesn't take the initial value, while fold does.
So reduce using fold is something like
@items || die "horribly";
foldl &fn, @items[0], @items[1..]
... while fold using reduce is:
reduce &fn, ($initial, @items)
I think both are useful, depending on the circumstances.
Miro
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