Search⌘ K
AI Features
Home
Courses
Mastering Modern Perl: Writing Efficient and Maintainable Code

Types of Scope II

Explore how dynamic scope differs from lexical scope in Perl, including the role of package variables and localization. Understand lexical pads for managing variable storage in recursive calls, and discover how the state keyword allows persistent lexical variables with one-time initialization to improve function behavior and caching.

We'll cover the following...

Dynamic scope

Dynamic scope resembles lexical scope in its visibility rules. Still, instead of looking outward in compile-time scopes, lookup traverses backward through all of the function calls we’ve made to reach the current code. Dynamic scope applies only to global and package global variables (since lexicals aren’t visible outside their scopes). While a global package variable may be visible ...

Perl
our $scope;
sub inner {
    say $scope;
}
sub main {
    say $scope;
    local $scope = 'main() scope';
    middle();
}
sub middle {
    say $scope;
    inner();
}
$scope = 'outer scope';
main();
say $scope;

The ...