Perhaps you meant $terminal->[0]?

-- Randal L. Schwartz, Perl hacker
Be sure to read my standard disclaimer if this is a reply.

By reducing your subroutine to the bare essentials, we appear to get the following (with some variable name munging to make it easier to read):

my ($initial_enthalpy, $initial_entropy) 
    = get_initials ($terminal[0], $initial_enths[1], $initial_entros[1
+]);

sub get_initials {
  my ($terminal, $enths, $entros) = @_;

  my ($initial_entropy, $initial_enthalpy);
  if ( $terminal =~ /^[GC]/) )    {
    return ($enths, $entros);
  }
}
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Which is the same as:

my ($initial_enthalpy, $initial_entropy) = $terminal[0] =~ /^[GC]/
    ? ($initial_enths[1], $initial_entros[1])
    : (undef undef);
[download]

From what I see, your += assignments in the subroutine suggest that you expect these variables to be incremented, even though their initial scope is in this subroutine and thus will be equivalent to zero wheen incrementing. Perhaps if you tell us what you're trying to do (and show us sample inputs and outputs), we can clear this up for you.

Cheers,
Ovid

New address of my CGI Course.
Silence is Evil (feel free to copy and distribute widely - note copyright text)

use strict;
use warnings;
[download]

—John

Can anyone spot anything?

my @ar = qw/ foo bar baz /;
func(\@ar);

sub func {
  my $ar = shift;

  ## note the dereference via ->
  print $ar->[0];
}

__output__

foo
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_________
broquaint

Isn't that the same as saying:

my $ar = qw/ foo bar baz /;
func(\@ar);

sub func {
  my $ar = @_;
}
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I ask, 'cause that's what he did.

--Coplan

Some misunderstandings:

my $ar = qw/ foo bar baz /;

In the line above, you're assigning a list in scalar context. You're going to get the last element of that list (baz) assigned to $ar.

func(\@ar);

That will throw a warning under strict because you declared a scalar ($ar), not an array (@ar).

my $ar = @_;

Now you're accessing an array in scalar context. This will result in $ar being set the the number of elements in @_. Here's a quick demonstration:

$ perl -e 'sub aa {my $a = @_;print $a}; aa(qw(foo bar baz))'
3
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I realie those seem tricky and frankly, it's often a matter of memorizing how those things behave.

Cheers,
Ovid

New address of my CGI Course.
Silence is Evil (feel free to copy and distribute widely - note copyright text)