\Q and \E vs. quotemeta?

OK, that seems clear hdp, but I'm confused by the following snippet (using \t instead of \a for visibility) in which perlfunc:quotemeta appears to behave differently than /Q/E:

$foo = "\tfoo";
$_ = ">>ha<<\n";  s/ha/$foo/;      print;
$_ = ">>ha<<\n";  s/ha/\Q$foo\E/;  print;
quotemeta $foo;  # update: this is doing nothing!
$_ = ">>ha<<\n";  s/ha/$foo/;      print;

$foo = '\tfoo';
$_ = ">>ha<<\n";  s/ha/$foo/;      print;
$_ = ">>ha<<\n";  s/ha/\Q$foo\E/;  print;
quotemeta $foo;  # update: this is doing nothing!
$_ = ">>ha<<\n";  s/ha/$foo/;      print;
[download]

which produces:

>>      foo<<
>>\     foo<<
>>      foo<<
>>\tfoo<<
>>\\tfoo<<
>>\tfoo<<
[download]

What am I forgetting here?

Update Aarghhh! How bloody embarrassing! Thanks tye, that's what I get for minimizing my keystrokes!
Useless use of quotemeta in void context at D:\Perl\tmp\quotemeta.pl line 9.
Useless use of quotemeta in void context at D:\Perl\tmp\quotemeta.pl line 15.
/me smacks himself in the forehead

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(tye)Re: \Q and \E vs. quotemeta? by tye (Sage) on Apr 30, 2001 at 20:52 UTC
`$foo= '\t\a\b\c'; print "foo=($foo)\n"; quotemeta $foo; print "foo=($foo)\n"; $foo= quotemeta $foo; print "foo=($foo)\n"; __END__ Produces: foo=(\t\a\b\c) foo=(\t\a\b\c) foo=(\\t\\a\\b\\c)` [download] That is, quotemeta doesn't modify in place, it returns a modified value so your uses of quotemeta are useless. If you had turned on warnings, then you would have been told: `Useless use of quotemeta in void context at quotemeta.pl line 5.` which is why we often urge people to do stuff like that. q-: - tye (but my friends call me "Tye")	[reply] [d/l] [select]

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(tye)Re: \Q and \E vs. quotemeta?
by tye (Sage) on Apr 30, 2001 at 20:52 UTC

$foo= '\t\a\b\c';
print "foo=($foo)\n";
quotemeta $foo;
print "foo=($foo)\n";
$foo= quotemeta $foo;
print "foo=($foo)\n";
__END__
Produces:
foo=(\t\a\b\c)
foo=(\t\a\b\c)
foo=(\\t\\a\\b\\c)
[download]

That is, quotemeta doesn't modify in place, it returns a modified value so your uses of quotemeta are useless.

If you had turned on warnings, then you would have been told: Useless use of quotemeta in void context at quotemeta.pl line 5. which is why we often urge people to do stuff like that. q-:

tye

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