Perl : use strict 'refs';

#strictStudy.pl


use strict 'refs';
$ref = \$foo;
print $$ref;
$ref = "foo";


#print $$ref;
#note:symbolic reference forbidden.


$file = "STDOUT";
$file2 = "STDIN";
print $file," Hi!";
#note:function case is exception case.
$bar = \&{'foo'}; #$bar get ref to function foo
&$bar;#Use &$bar to invoke the referenced function.


sub foo{
    print "foo function invoked..\n";
}
sub bar{
    print "bar function invoked...\n";
}


#輸出結果:
STDOUT Hi!foo function invoked..