Merging the semantics of for and while in Perl is very hard. I experimented for years and it always came with a penalty, like performance or fuzzy variable scope.

E.g. you can use syntactic sugar to define 2 subs from(&;@) loop(&) with prototypes to define your own loop construct like

from { LIST | ITER } $a,$b => loop { BODY }

an from would check if ITER was blessed to an iterator class and act accordingly.

But you can guess that this would be slow. I suppose even if implemented in XS it would be slow.

BUT "it is ONE user interface".

Are you willing to pay that price?

Cheers Rolf
(addicted to the 𐍀𐌴𐍂𐌻 Programming Language :)
Wikisyntax for the Monastery

In reply to Re^3: Using lazy list with a for loop by LanX
in thread Using lazy list with a for loop by Anonymous Monk

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