use strict; use warnings; use feature 'say'; sub f {a => 1, b=>2} my $foo = f(); my $bar = join '_', f(); say $foo; say $bar; #outputs 2 a_1_b_2 #### sub f {a => 1, b=>2} my @all_key = keys f(); #### sub f {a => 1, b=>2} my %h = (c => 3); say keys %h, f(); #output: c #### sub f {a => 1, b=>2} my %h = (c => 3); say keys f(), %h; #warnings: Experimental keys on scalar is now forbidden at perl.pl line 11. Type of arg 1 to keys must be hash or array (not subroutine entry) at perl.pl line 11, near ")," Execution of perl.pl aborted due to compilation errors. #### use strict; use warnings; use feature 'say'; sub f {a => 1, b=>2} my $foo = f(); my $bar = join '_', f(); say $foo; say $bar; #output 2 a_1_b_2 sub f {a => 1, b=>2} my @all_key = keys f(); #warnings: Experimental keys on scalar is now forbidden at call_art.pl line 7. Type of arg 1 to keys must be hash or array (not subroutine entry) at call_art.pl line 7, near ");" Execution of call_art.pl aborted due to compilation errors. sub f {a => 1, b=>2} my %h = (c => 3); say keys %h, f(); #output ca1b2 sub f {a => 1, b=>2} my %h = (c => 3); say keys f(), %h; #warnings: Experimental keys on scalar is now forbidden at call_art.pl line 8. Type of arg 1 to keys must be hash or array (not subroutine entry) at call_art.pl line 8, near ")," Execution of call_art.pl aborted due to compilation errors.