RE: scalarmap - some new perl syntax

This is fun to play with. A few comments:

You wrote:
```
    my $fancy_join = scalarmap {  $a . $b } "", 'a'..'z';
[download]
```
This isn't doing what you think it is. If "" is the initial element, it's not going to be used to join each of the elements together into a string. Well, it's not going to do so as join would do it, at least. Try it with something like ", " to see.
In case you don't feel like trying it, here's the results of:
```
    print  scalarmap {  $a . $b } ", ", 'a'..'z';
[download]
```
```
    , abcdefghijklmnopqrstuvwxyz
[download]
```
I'm not sure I like the use of $a and $b. That's too reminiscent of sort, where the elements are "equivalent" in terms of their relation to each other; they're both elements in the list, in other words.
Here, though, $a is actually the *total* of whatever has come before in the list, where "total" means whatever you've defined it to mean in your code reference. And $b is just a lowly element. :)
So they're not on the same "level" of meaning as it were. I like using $_ inside of map blocks. If it were me, I'd change $b to $_, and $a to something special and local, like $T, for total, or something like that. I don't know.
This is just getting snippy :), but I don't like having the initial value being the parameter following the code block. Because the code block is "acting" on the list, so it makes sense to follow the code block with the list.
Maybe move the inital value in front of the code block?

Anyway, I like this. Thanks for posting it.

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RE (tilly) 2: scalarmap - some new perl syntax by tilly (Archbishop) on Sep 01, 2000 at 07:29 UTC
An advantage to $a and $b is that they [utomatically pass strict. (Specifically because of sort.) This is also a disadvantage, but oh well.	[reply]
RE: RE (tilly) 2: scalarmap - some new perl syntax by ncw (Friar) on Sep 01, 2000 at 11:32 UTC
That is why I chose $a and $b, because of the sort magic. I did consider setting $_ to a 2 element anonymous array, then you'd use it like this. `scalarmap { $_->[0] + $_->[1] } 0, @z;` [download] But that isn't as elegant. I considered using $a and $_ but that offended me too! I see from merlyn's post below that the maker of List::Util::reduce came to the same conclusions...	[reply] [d/l]
RE: RE: scalarmap - some new perl syntax by ncw (Friar) on Sep 01, 2000 at 11:48 UTC
You are quite right about the join thing! I just wanted an example with a string and I didn't intend it to be a full blown join replacement! See my reply to tilly for $a and $b. I agree with you about having the initial value first, but I couldn't get it to work. Trying to prototype the subroutine as ($&@) meant that I couldn't call it for some reason. If I try this :- `sub scalarmap ($&@) { local ($a, $b) = ( shift ); my $code = shift; foreach $b (@_) { $a = &$code; } return $a; } my @array = 1..10; my $sum = scalarmap 0, { $a + $b } @array;` [download] Then when I run it I get `Array found where operator expected at scalarmap2.pl line 32, near " +} " (Missing operator before ?) syntax error at scalarmap2.pl line 32, near "} @array"` [download] Which is puzzling...	[reply] [d/l] [select]