Mastering Modern Perl: Writing Efficient and Maintainable Code/

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State vs Closures and Pseudo-State

State vs Closures and Pseudo-State

Learn about the difference between state and closure and between state and pseudo-state.

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State vs. closure

Closures use lexical scope to control access to lexical variables, even with named functions:

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{
  my $safety = 0;
  
  sub enable_safety { $safety = 1 }
  sub disable_safety { $safety = 0 }
  
  sub do_something_awesome {
    return if $safety;
    say "Keep learning with Educative";
  }
  enable_safety();
  do_something_awesome();
  disable_safety();
  do_something_awesome();
}

All three functions encapsulate that shared state without exposing the lexical variable outside their shared scope. This idiom works well for cases where multiple functions access that lexical, but it’s clunky when only one function does.

Use state variables

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