Re: [Solved] How does map work?

[Laurent_R]

Although the code below is quite similar to what BrowserUk has posted, I post here two versions of the "my_map" function that I wrote a couple of weeks ago for a tutorial that I am in the course of writing in French on functional programming in Perl. The first one works similarly to Perl's map function in the sense that if the code block modifies $_, then the original array is modified:

sub my_map (&@){
    my $code_ref = shift;
    my @d ;
    push @d, $code_ref->($_) for @_;
    return @d;
}

The second one is more like a pure functional version of map having no side-effect on the original array:

sub my_map (&@){
    my $code_ref = shift;
    my @d = @_;
    $_ = $code_ref->($_) for @d;
    return @d;
}

[LanX]

may I ask, why you pass $_ as argument?

[Laurent_R]

Well, yes, you are right, this is not needed. But this was an example for a tutorial, I wanted it to be explicit to explain clearly what is going on. Thank you for your remark, I need to add at least one example without $_ in my tutorial.