our
- our TYPE VARLIST
- our VARLIST : ATTRS
- our TYPE VARLIST : ATTRS
our
makes a lexical alias to a package (i.e. global) variable of the same name in the current package for use within the current lexical scope.our
has the same scoping rules asmy
orstate
, meaning that it is only valid within a lexical scope. Unlikemy
andstate
, which both declare new (lexical) variables,our
only creates an alias to an existing variable: a package variable of the same name.This means that when
use strict 'vars'
is in effect,our
lets you use a package variable without qualifying it with the package name, but only within the lexical scope of theour
declaration. This applies immediately--even within the same statement.This works even if the package variable has not been used before, as package variables spring into existence when first used.
Because the variable becomes legal immediately under
use strict 'vars'
, so long as there is no variable with that name is already in scope, you can then reference the package variable again even within the same statement.If more than one variable is listed, the list must be placed in parentheses.
- our($bar, $baz);
An
our
declaration declares an alias for a package variable that will be visible across its entire lexical scope, even across package boundaries. The package in which the variable is entered is determined at the point of the declaration, not at the point of use. This means the following behavior holds:Multiple
our
declarations with the same name in the same lexical scope are allowed if they are in different packages. If they happen to be in the same package, Perl will emit warnings if you have asked for them, just like multiplemy
declarations. Unlike a secondmy
declaration, which will bind the name to a fresh variable, a secondour
declaration in the same package, in the same scope, is merely redundant.An
our
declaration may also have a list of attributes associated with it.The exact semantics and interface of TYPE and ATTRS are still evolving. TYPE is currently bound to the use of the
fields
pragma, and attributes are handled using theattributes
pragma, or, starting from Perl 5.8.0, also via theAttribute::Handlers
module. See Private Variables via my() in perlsub for details, and fields, attributes, and Attribute::Handlers.Note that with a parenthesised list,
undef
can be used as a dummy placeholder, for example to skip assignment of initial values:our
differs fromuse vars
, which allows use of an unqualified name only within the affected package, but across scopes.