How do I toggle printing to STDOUT/STDERR dynamically in Perl?

Question

I'm curious if I can toggle between printing to STDOUT or STDERR based on some value or inline expression (without using an if statement).

print ($someFlag ? STDOUT : STDERR) "hello world!"

Obviously, that syntax doesn't work.

Answer 1

I think this will do what you want:

print {$someFlag ? *STDOUT : *STDERR} "hello world!";

A similar example can be seen in the documentation for print. Use typeglobs so that it will run under use strict.

Another strategy is to define your own printing function that will behave differently, depending on the value of $someFlag.

Answer 2

Do you need to evaluate for each call to print?

If not, would this work for you:

my $redir = $someFlag ? STDOUT : STDERR;
print $redir "hello world!\n";