Re^6: What technical benfits perl offers over python + few more questions. (generator/iterator/closure)


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Re^6: What technical benfits perl offers over python + few more questions. (generator/iterator/closure)

by LanX (Sage)

on Nov 13, 2021 at 20:20 UTC ( #11138797=note: print w/replies, xml )

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in reply to Re^5: What technical benfits perl offers over python + few more questions.
in thread What technical benfits perl offers over python + few more questions.

> My understanding of an iterator function

here an example of a generator creating an iterator and using closure variables.

use strict;
use warnings;

sub gen_range_step {
    my ( $start,$stop,$step ) = @_ ;

    my $current = $start;

    return sub {
        my $val   = $current;
        $current += $step;
        return $val if $val <=$stop;
        return;
    }
}

my $iter = gen_range_step(5,20,4);

while ( my ($val) = $iter->() ) {
    print "$val\n";
}
[download]

C:/Strawberry/perl/bin\perl.exe -w d:/tmp/pm/generator_iterator.pl 5 9 13 17 Compilation finished at Sat Nov 13 21:18:20
[download]

> but keep in mind I studied engineering and not computer science

I studied mathematics and some CS, and FP was never mentioned.

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

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Re^7: What technical benfits perl offers over python + few more questions.
by talexb (Chancellor) on Nov 13, 2021 at 21:55 UTC

Thanks for the explanation -- the difference is that Perl can return a CODEREF, but C doesn't have that functionality. It would be possible to initialize a function to behave like an iterator, but without a great deal of jumping through hoops, you wouldn't be able to run multiple different iterators, as your Perl example could.

That's OK -- without C, you wouldn't have pretty much any of the modern languages I can think of (Perl, Python, PHP). And C is still an amazing language.

Alex / talexb / Toronto

Thanks PJ. We owe you so much. Groklaw -- RIP -- 2003 to 2013.

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