Cannot fire subroutine inside a hash of subroutines in perl

Hi I'm quite new to perl. I have a perl hash containing subroutines. I've tried to run it in various ways that I found online. But nothing seems to work. My code :

%hashfun = (

start=>sub { print 'hello' },
end=>sub { print 'bye' } 

);

And I've tried the following and more.

print "\n $hashfun{start} \n";

which results in the following output:

CODE(< HexaDecimal Value >)

Then I tried

print "\n $hashfun{start}->() \n";

which results in the following

CODE(< HexaDecimal Value >) ->()

How to fix?

Solution

Your last attempt ist the right syntax, but in the wrong place. You cannot run code inside of a string interpolation¹. Move it outside of the double quotes "".

print "\n";
$hashfun{start}->();
print"\n";

It's important not to print the actual call to $hashfun{start}, because that would return 1. That's because a sub in Perl always returns the return value of the last statement inside the sub (which can be a return). Here, it's a print. And the return value of print is 1 if the printing succeeded. So print "\n", $hashfun{start}->(), "\n"; would output

hello
1

^{1) Actually you can, but you really shouldn't.print "\n@{[&{$hashfun{start}}]}\n"; will work. It's very magical and you should really not do that.}

^{Because arrays can be interpolated into strings, an array deref works inside of double quotes. The stuff inside that deref is being run, so the &$hashfun{start} (which is a different way of calling the coderef) gets run. But because it returns 1 and that's not an array ref, we need to wrap it in [] to put it into an array ref that is then being dereferenced. Please don't use that!}