CODEWITHSUNDEEP
perlsubroutine
Vantuz
Vantuz

Reputation: 48

Defining lexical variable after defining subroutine

In Perl if you try to lexically declare variable with my after you declared a subroutine, this subroutine won't see this variable. However, subroutine declared after the variable will see the variable:

sub lol {
    if (@arr) {
        print "defined\n";
    } else {
        print "not defined\n";
    }
}
my @arr = (1,2,3);
sub lol2 {
    if (@arr) {
        print "defined\n";
    } else {
        print "not defined\n";
    }
}
lol; #prints "not defined"
lol2; #prints "defined"

However, if you set a variable without declaring it (@arr = (1,2,3);) or declare variable with our, both subroutines will see the variable.

Is it a bug or a feature?

Upvotes: 0

Views: 97

Answers (1)

mpapec
mpapec

Reputation: 50657

All variables which are not defined with my are implicitly our (global/package) variables. So it is a feature. use strict; pragma will force you to either use our or my explicitly in variable declaration.

To be more precise, quote from perldoc

strict vars

This generates a compile-time error if you access a variable that was neither explicitly declared (using any of my, our, state, or use vars ) nor fully qualified. (Because this is to avoid variable suicide problems and subtle dynamic scoping issues, a merely local variable isn't good enough.)

Upvotes: 1

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