execute function with name passed as string parameter

[rgcosma]

Hello good Monks,
I'm trying to pass the name of a function as parameter, and thought the below would work:

perl -e '$choice='1'; %hash=( '0' => &one, '1' => &two ); ${\$hash{$ch
+oice}}; sub one {print "one"}; sub two {print "two"}'

On execution, it prints "onetwo" while I expected it to run only $hash{1}? What am i doing wrong?

[Utilitarian]

You are not assigning a code_ref in your hash, but rather the out put of your routines, this causes them to run on assignment.

perl -e '$choice="1"; %hash=( 0 => one, 1 => two ); sub one {print "on
+e\n"}; sub two {print "two\n"} &{$hash{$choice}}'
two

[shmem]

What the other monks said, but TIMTOWTDI. You can also store subroutine references in your hash and execute them.

perl -le '$choice='1'; %hash=( '0' => \&one, '1' => \&two ); $hash{$ch
+oice}->(); sub one {print "one"}; sub two {print "two"}'

You could also call the subroutine reference via &{$hash{choice}} - but be aware that there's a subtle difference:

$\="\n"; # output record separator
$choice='1';
%hash=( '0' => \&one, '1' => \&two );
@_ = "fish";
$hash{$choice}->();
&{$hash{$choice}};
one;
&one;

sub one { print "one", @_ }
sub two { print "two", @_ }
__END__
two
twofish
one
onefish

That is, &sub, &$sub, &{gimme_a_subref()} and so on - without parens - pass the current @_ to the called subroutine. Of course, &{$hash{$choice}}() - with parens - passes an empty list.

[rgcosma]

OK, so it was a syntax misunderstanding, thank you all.

[chakreey]

& symbol in &one, &two is meant for calling subroutines. If your intention is not to call subroutines, but just assign subroutine names, then, use 'one', 'two' For calling subroutine, use &{$hash{$choice}}

perl -e '$choice='1'; %hash=( '0' => 'one', '1' => 'two');&{$hash{$choice}}; sub one {print "one"};sub two {print "two"}'

[NetWallah]

Simpler calling convention for using a variable as a sub-name - use parens:

perl -e '$choice="1"; %hash=( 0 => one, 1 => two ); sub one {print "on
+e\n"}; sub two {print "two\n"};$hash{1}()'

prints : "two"