While building up regex strings, I came across this conundrum. For example, 
my $x = "(quantifier)";
my %x = ( "1" => "(hash_value)" );
my $z = 'quantifier hash_value';

print "_$1_\n" if $z =~ /$x{1}/;         # {1} is quantifier
print "_$1_\n" if $z =~ /@{[$x{1}]}[0]/; # {1} is hash key 

__END__

_quantifier_
_hash_value_

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(1) How does Perl disambiguate (a) exactly 1 occurence of $x and (b) the hash value $x{1}?

(2) You can see that Perl chooses (a) for /$x{1}/. If I want (b), is there a better way than @{[$x{1}]}[0]?

(3) If we had it to do over, is there a better way for Perl to resolve this?

-QM
--
Quantum Mechanics: The dreams stuff is made of

In reply to Hash Key vs. Quantifier Ambiguity in Regex Context by QM

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