I belive '+' has some importance.

if (!defined($how_decide) || lc($how_decide) eq 'header') {
            return +($r->header_in('Accept-Encoding')||'') =~ /gzip/;
          } elsif (lc($how_decide) eq 'user-agent') {
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updated: Removed the duplicate "found" word in my comment.

In that example the + tells perl that the parens are not enclosing the arguments to a function call, so it is parsed correctly.

Here's a nice simple example of when you might need to use it:

$ perl -e 'print (2+3)/5'
5
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How on earth does that print 5? Because it evaluates as "print the result of 2 + 3, then divide print's return value (which is 1 if print worked) by 5, and then do nothing with the result". This is obvious if you stick another print in there:

$ perl -e 'print print (2+3)/5'
50.2
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which is parsed as:

print((print(2+3))/5)

I belive '+' has some importance.

For me, return values of +0, -0, and 0 are indistinguishable from each other - which means that the '+' has no significance at all:

C:\_32>perl -MDevel::Peek -e "Dump(+0)"
SV = IV(0x1fe2d28) at 0x343cbc
  REFCNT = 1
  FLAGS = (PADBUSY,PADTMP,IOK,READONLY,pIOK)
  IV = 0

C:\_32>perl -MDevel::Peek -e "Dump(-0)"
SV = IV(0x432d2c) at 0xd73cec
  REFCNT = 1
  FLAGS = (PADBUSY,PADTMP,IOK,READONLY,pIOK)
  IV = 0

C:\_32>perl -MDevel::Peek -e "Dump(0)"
SV = IV(0x2492d28) at 0x23cbc
  REFCNT = 1
  FLAGS = (PADBUSY,PADTMP,IOK,READONLY,pIOK)
  IV = 0
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(Replace the double quotes with single quotes if you're on a *nix-type operating system.)

Cheers,
Rob

Just note that -.0 is distinct from .0.

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