It was thus said that the Great A. Pagaltzis once stated:
> * Sean Conner <s...@conman.org> [2006-12-22 21:35]:
> > But *neolithic code*?
>
> Yeah.
>
> > What? I should do
> >
> > map
> > {
> > open INPUT $_;
> > &do_some_process;
> > close INPUT;
> > } @ARGV;
>
> Almost. You can do it that way if you prefer it, but in cases
> such as this one I'd write it like so:
>
> for ( @ARGV ) {
> # ...
> }
Ah, the Bronze Age code (more on this in a bit).
> Or you can call it `foreach` if you like that better.
> Independently of that, if you don't like the `$_`, you can name
> a variable explicitly:
>
> foreach my $file ( @ARGV ) {
> # and use $file here
> }
>
> There is never a good reason to use `for(;;)` in Perl. If you
> need to iterate over indices, you do it this way:
>
> for my $i ( 0 .. $#ARGV ) {
> # ... and use $ARGV[ $i ] here
> }
>
> As a side effect, you get to lose the `<` vs `<=` source of
> off-by-one errors.
I think this makes Peter daSilva's argument about Perl and it's "There Is
More Than One Way To Do It" paradigm. Let's see ...
for ( <init> ; <cond> ; <incr> )
for ( <max-count> )
for <var> ( <lower-bound> .. <upper-bound> )
No wonder it's taking so long for Perl 6 to come out---the parser alone
must be horribly complex to disambiguate all these constructs (and from
other messages, the Parl 6 parser is even *more* complex).
Anyway, the bit about your code being the Bronze Age.
If the way I do it is neolithic, your's isn't much better. It still
implies an order to the operations, whereas map doesn't have that
restriction and the code can be parallelized easier, and thus is a more
modern way of programming, especially given the rise of multicore processors
in even home PCs.
That's why I picked that particular example.
> But there is relatvely rarely even a need to index into an array.
> Most of the time you just want to either iterate over the whole
> thing or push/pop/shift/unshift elements. Makes code easier to
> read, too, and reduces coupling even at the most local scales.
Perhaps for what you do. I just checked some Perl code I wrote and I hit
specific spots in multiple arrays and can't see a way around that (LOG
refers to a webserver log file):
while(<LOG>)
{
my @entry = m/$c_parse_apache/o;
my $size = @entry;
if ($size)
{
$g_hits++;
$g_transfer += $entry[LOG_BYTES] unless $entry[LOG_BYTES] eq "-";
$g_hits[$entry[LOG_STATUS] / 100]++;
&sort_entry(@entry);
}
}
If you have a better way of coding this, I'm all ears (in fact, if you
want the entire script, I'm happy to send it to you ... )
-spc (And don't ask me how the data is structured---I don't recall, since
Perl lacks proper structures ... )
