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Re: Can you find the name of a variable?

by afoken (Parson)
on Nov 14, 2009 at 10:57 UTC ( #807126=note: print w/ replies, xml ) Need Help??


in reply to Can you find the name of a variable?

If you want to know the name of a variable, you usually try to do something stupid. Most times, the answer is to use a hash instead. Also in this case, you can use a hash to get named parameters instead of positional parameters.

Something like this:

sub blah { my %args=(@_); foreach my $needed (qw( foo bar baz )) { exists $args{$needed} or die "blah() needs a $needed parameter +"; } # .... } blah(foo => 42, bar => "don't forget this", baz => 'oh!'); blah(foo => 42, baz => 'oh!'); # <-- will die()

Back to the "what's the name of the variable problem". What should a hypothetical nameThatVariable() function return for the following cases?

$foo=42; print nameThatVariable($foo); # '$foo', of course. $foo=[ 42 ]; print nameThatVariable($foo); # still '$foo'. @bar=( 42 ); print nameThatVariable(@bar); # '@bar', of course. $baz=$foo=\@bar; print nameThatVariable($foo); # 'reference to @bar' or '$foo'? print nameThatVariable($baz); # 'reference to @bar' or '$foo' or '$baz +' ? print nameThatVariable(\@bar); # 'reference to @bar'? print nameThatVariable(do { my $tmp=23 }); # '$tmp'? print nameThatVariable([ 23,45 ]); # ?

Alexander

--
Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)


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