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Messing w/ print

DEBUGGING AND LEARNING

Sometimes I mess around with Perl like this:

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#!/usr/bin/env perl
use strict;
use warnings;

sub post {
    my ($a, $b) = @_;
    return $a + $b;
}

my throw_up = post(22, 33);
print(throw_up);
Just trying to write a simple script to sum two numbers and print the result. Here’s what I started with ᕕ( ᐛ )ᕗ When I ran that random script, I got this error:

No such class throw_up at app.pl line 11, near "my $throw_up"
syntax error at app.pl line 11, near "my $throw_up ="
Execution of app.pl aborted due to compilation errors.

I was a bit confused, So I looked carefully at the message, and turns out. The error was due to forgetting the dollar sign ($) in front of my variable haha.. I forget that in Perl, variables need that $ to show they’re scalars. So I fixed my code like this:

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my $throw_up = post(22, 33);
print $throw_up;

That fixed the error, but I still had some questions in my mind, what if:

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my $throw_up = 5;
print ($throw_up) + 2;

I got some warnings that made me scratch my head 🙆:

Useless use of addition (+) in void context at app.pl line 12.

The result is just 5, I didn’t understand why the + 2 didn’t seem to change anything. I thought maybe printing $throw_up again would show that the addition somehow affected its value. So I ran this code:

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print($throw_up, "\n") + 2;
print $throw_up, "\n";

The output still showed 5, not 7. It became clear that the addition was ignored, even after printing $throw_up again. Such a stupidity ଘ( ᐛ ) ଓ

To simplify things, I rewrote the code:

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my $result = $throw_up + 2;
print $result, "\n";
And like this:

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print $throw_up + 2, "\n";

And also like this:

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print($throw_up + 2, "\n");

All of these work.

Remember about context, context, context...
It's made clearer and easier to understand this wierdo language in my opinion ╮ (. ❛ ᴗ ❛.) ╭