I honestly don't see the point. A given programmer that doesn't read the FAQs now isn't going to start because of a shiny new module. It's more important that the FAQ give a good answer and that we point people tward it when these questions come up.

borisz,
• ...hardest part is to explain why someone should use this module in favor of List::Util
This is a good point in general. Perhaps the README should include a FAQ for questions like, why isn't there an X function. The reply would be because it is part of module Y.
• I personally dislike uppercase functionnames a lot!
I have a tendency to name my subs like Add_Name and am not sure why I did all uppercase.
• And there is already List::MoreUtils, perhaps your functions fit more in this module.

From my original post:

I want to stress that this post is about the idea in general and not this specific proof of concept.

The reason the proposed name was Tool::Box and not Functions::List::Util::Forgot was because I see it as being a hodge podge of functions (such as getting the intersection of two arrays). These functions were only examples of what I was thinking about and not specific functions that I think should be included (concepts not specifics).

Cheers - L~R

jdporter,
Just to recap so I am clear:
• Relatively small snippets by themselves do not belong in a module
• Collections of related snippets may warrant an appropriately named module
• A "left overs" or "hodge podge" of snippets doesn't belong in a module, but should be part of the programmer's knowledge base.
Just MHO

That's what I asked for and thanks for giving it to me. Like I said, I could see it going both ways. Still not sure I am convinced either way though.

Cheers - L~R

Let's carefully consider this one:

A "left overs" or "hodge podge" of snippets doesn't belong in a module, but should be part of the programmer's knowledge base.

The snippets that are common knowledge to a significant portion of the community ought to be taken out of our personal, back-of-the-brain closets, dusted off, and given proper names. Let us place them firmly in the common, community-wide knowledge base.

Why should every programmer in the community have their own pet versions of common but "noncollectable" functions? If there is value in giving something a name, give it a name. If there is value in collecting something, collect it.

Who cares how big the thing is or whether there's already enough stuff like it to form a ready-made home for it? If the cost of giving it a name and collecting it and then using it to solve problems is less than the cost of solving the problems otherwise, then it has earned its name and its place. What other consideration is there?

Cheers,
Tom

Tom Moertel : Blog / Talks / CPAN / LectroTest / PXSL / Coffee / Movie Rating Decoder

package Increment;
use base qw(Exporter);
@EXPORT = qw(increment);
sub increment {
    $_[0]++
}
# (...)
[download]

But when you come to things like a min/max function or a slurp function, there is more room for debate. While I'll happily use the functions in List::Util because they are part of the core (at least if I'm targetting perl-5.8.0+), I just never use any of the file slurping modules on CPAN. Adding another dependency for something that I can write in one line of code seems utterly unnecessary.

Second, the all-caps are a bit much. (They burn my eyes.)

Third, I like the pre-loading refinement. (Personally, I wouldn't use them like this:

    my $min = MIN(1..10)->();
[download]

    my $min = MIN->(1..10);
[download]

But the refinement does have value for finding min-maxes and max-mins:

    my $max_of_at_least_zero = MAX(0);
    $max_of_at_least_zero->($_) while <>;
    # ...
[download]

Fourth, let's load the tool-box up! How about some new additions?

• read_all – slurp filehandle
• read_all_from_path – open, slurp, close
• zip – merge parallel arrays
• zip_with – merge parallel arrays with a given "zipper" function
• foldl, foldl1, foldr, foldr1, scanl, scanl1, scanr, scanr1 – more friends from functional programming
• curry – everybody loves curry

Thanks for getting the ball rolling.

Cheers,
Tom

tmoertel,

• First, this is a mighty fine idea...
Thank you. I think it might be, but I would have preferred to hear from some relative newcomers.
• Second, the all-caps are a bit much...
I have changed them. I am not sure why I used all caps as I don't normally.
• Third, I like the pre-loading refinement...
This was a hard decision with regards to DWIM. I would have preferred to have the ability in calling syntax to determine if they just want to run one time and get an answer versus returning a function. This seemed like an acceptable comprimise.
• Fourth, let's load the tool-box up! How about some new additions?...
I am more than happy to be a co-author. We would decide when/if we release it who is responsible for maintenance.

Cheers - L~R

You can tell CPAN that you are co-maintainers so that both of you can upload new versions.

tmoertel,
I decided to get rid of max/min even if it is more functional than what List::Util provides. I think the only List::Util function worth making a closure out of is reduce.

Additionally, I changed the calling syntax a bit. If you call a function with an argument list it will return the result of that list instead of a function. The trouble, as pointed out by diotalevi, is what to do if it is called with an empty list/array. Perhaps using different function names?

Read more... (6 kB)

Cheers - L~R

Update:Slight modification (removing a function) after diotalevi pointed out it was equivalent to another List::Util function

Why do you define the anonymous subroutine every time you call the function? Your anonymous subs aren't closures - they're just anon subs. They don't close over anything, let alone anything in @_. Your functions would be much faster if you define the subrefs ahead of time. Your functions would also be simpler because they just dispatch to the subref or return it, as needed.

Another item - you make the same mistake nearly every unique'ing function makes: what if I want to find unique objects or hashrefs? Much better is @uniq{@_} = @_; values %uniq. That way, you also respect any overloaded stringification I might use. Your uniq_ordered() function doesn't have this mistake.

Being right, does not endow the right to be rude; politeness costs nothing.
Being unknowing, is not the same as being stupid.
Expressing a contrary opinion, whether to the individual or the group, is more often a sign of deeper thought than of cantankerous belligerence.
Do not mistake your goals as the only goals; your opinion as the only opinion; your confidence as correctness. Saying you know better is not the same as explaining you know better.

In order for a library to be useful, programmers must understand it. A chimera-like interface that shifts depending on the number of arguments passed to a function or upon magic use-time flags only places hurdles on the track to understanding. I'm squarely with diotalevi: The interface should be clear and unchanging.

I recommend having separate functions for each behavior. For example, we could use the _acc suffix to denote accumulating functions that can be used to accumulate results iteratively. As long as we are clear and consistent in our usage, we can deliver both accumulating and non-accumulating functionality without making the library harder to understand.

One possible implementation:

    # factor out accumulating behavior:

    sub make_acc_fn(&@) {
        my $f = shift;
        $f->(@_);
        $f;
    }

    # mean

    sub mean { mean_acc(@_)->() }   # all-at-once version
    sub mean_acc {                  # accumulating-function version
        my ($tot, $cnt);
        make_acc_fn {
            $cnt += @_;
            $tot += $_ for @_;
            $cnt ? $tot / $cnt : undef;
        } @_ ;
    }

    # uniq

    sub uniq { uniq_acc(@_)->() }
    sub uniq_acc {
        my %uniq;
        make_acc_fn {
            @uniq{ @_ } = ();
            wantarray ? keys %uniq : scalar keys %uniq;
        } @_ ;
    }


    # examples

    print mean(1,2,3,5), $/;
    # 2.5

    my $m = mean_acc();
    print "$_ => ", $m->($_), $/ for 1..5;
    # 1 => 1
    # 2 => 1.5
    # 3 => 2
    # 4 => 2.5
    # 5 => 3

    print uniq(1,2,3,1..5), $/;
    # 41325

    my $u = uniq_acc(1,2,3);
    print "$_ => ", $u->($_), $/ for 1..5;
    # 1 => 132
    # 2 => 132
    # 3 => 132
    # 4 => 4132
    # 5 => 41325
[download]

Cheers,
Tom

Tom Moertel : Blog / Talks / CPAN / LectroTest / PXSL / Coffee / Movie Rating Decoder

For a read_all_from_path subroutine see File::Slurp (one of my must-have modules). An efficient read_all could probably be added there.

For zip, fold*, and scan* see Language::Functional. If you want a zip_with, patching Language::Functional would perhaps be a good idea.

For spices see Sub::Curry.

ihb

See perltoc if you don't know which perldoc to read!
Read argumentation in its context!