I bashed out some regexes to no avail - not an easy problem (well unless you are japhy or I0 - UPDATE: or The dreadpiratepeter ... man that was so simple!). Couple of suggestions if you want to continue this route:
  1. [^\s] is the same thing as \S
  2. you might be better off joining @ARGV into a string: 
    $_ = join ' ', @ARGV;

my %defaults;
$defaults{$1} = $2 while /([^\=]+)\=(\S+)/g;

    [download]
    but that doesn't work for escaped spaces ...
After getting tired of trying the regex way, i opted for something different: 
my %defaults = ();
my ($k,$v);
for (@ARGV) {
   if (($k,$v) = split('=',$_,2)) {
      $defaults{$k} = $v;
   }
   else {
      $defaults{$k} += " $v";
   }
}

[download]
This worked on the following execution: 
./foo.pl QUICK=BROWN\ FOX JUMPED=OVER\ THE\ LAZY\ DOG
Not that each space is escaped except the one before a 'key', otherwise this does not work.

Now, go ye forth and use a CPAN module to do this! ;) At least break one open and see how they solve the problem, which should hint at the complexity involved: what about multiple options? flag options? what about dashes in front of the keys? etc. Learning is good, but sometimes getting stuff done is better.

jeffa

L-LL-L--L-LL-L--L-LL-L--
-R--R-RR-R--R-RR-R--R-RR
B--B--B--B--B--B--B--B--
H---H---H---H---H---H---
(the triplet paradiddle with high-hat)

In reply to (jeffa) Re: Regular expression double grouping negation headache by jeffa
in thread Regular expression double grouping negation headache by JayBonci

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