Ok, then. Here's a code block that demonstrates how to do it by using a dependency structure: 
#!/usr/bin/perl

use strict;
use warnings;

my %vars;
my %depend;

while (<DATA>) {
  chomp;
  if (/^\s*(\w+)\s*=\s*(?:"([^"]*)"|(.*))/) {
    my ($name, $val) = ($1, $+);
    $vars{$name} = $val;
    $depend{$name} = [ $vars{$name} =~ /\$(\w+)/g ];
  }
}

expand(\%vars, \%depend);

sub expand {
  my ($varhash, $dephash, $queue) = @_;

  $queue ||= [ keys %$varhash ];

  # for each item in the queue
  for (@$queue) {

    # make sure its dependencies are expanded
    expand($varhash, $dephash, $dephash->{$_});

    # then interpolate the variables in this item
    $varhash->{$_} =~ s/\$(\w+)/$varhash->{$1}/g;
  }
}

use Data::Dumper;
print Dumper(\%vars);

__DATA__
VAR1 = "say $VAR2"
VAR2 = "hi $VAR3"
VAR3 = jeff

[download]
You can see I parse my variables a little differently. If it's more complex for you, then so be it, but I used simple cases. I used the $+ variable because I want to match the string INSIDE quotes (not the quotes themselves) or else an un-quoted string, and I don't know which of these matches, so $+ gives me the last matching capture group. It's like writing defined($2) ? $2 : $3 in this case, but I didn't want to do that.

You can see how expand() looks similar to the post-order traversal code I showed you a day or two ago. It's a similar concept. The function, when called with only the two hashrefs, uses the keys of the %vars hash as its queue. Each recursive call uses the dependent variables of the current one as its queue. I hope it's understandable.

_____________________________________________________
Jeff[japhy]Pinyan: Perl, regex, and perl hacker, who'd like a job (NYC-area)
s++=END;++y(;-P)}y js++=;shajsj<++y(p-q)}?print:??;

In reply to Re: Re: Re: simulating bash by japhy
in thread simulating bash by agaffney

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.