When should you prefer my vs our vs local, and when should you avoid it?

In Perl, the use of variable declarations (my, our, and local) can significantly affect how variables are scoped and accessed within your code. Understanding when to use each can lead to more effective programming practices.

my

Use my to declare a variable with a lexical scope. This means that the variable is only accessible within the block in which it was defined. This is useful for encapsulating variables and avoiding conflicts.

my $variable = "I am local to this block"; { my $inner_variable = "I am local to the inner block"; print $inner_variable; # Works } print $inner_variable; # Error: Variable not found

our

Use our to declare a variable with package scope. This allows the variable to be accessed throughout the package, making it suitable for global variables when you need shared state.

our $global_variable = "I am accessible anywhere in the package"; sub example { print $global_variable; # Works }

local

Use local to temporarily change the value of a global variable within a certain scope. This is quite useful for overriding global variables in subroutines, but it can lead to hard-to-track bugs if overused.

our $global_variable = "Original value"; sub example { local $global_variable = "Changed value"; print $global_variable; # Works: prints "Changed value" } example(); print $global_variable; # Works: prints "Original value"

When to Avoid

Avoid using our and local unless necessary, as they can introduce bugs due to variable shadowing and side effects. Prefer using my for variable declarations whenever possible.


Perl variable scope my vs our vs local Perl programming practices lexical scope in Perl package variables in Perl

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