Perl Pocket Reference, 5th Edition

Packages and Modules

import module [ list ]

Usually imports subroutines and variables from module into the current package. import is not a built-in, but an ordinary class method that may be inherited from UNIVERSAL.

no module [ list ]

At compile time, requires the module and calls its unimport method on list. See use on the next page.

package namespace [ version ] [ block ]

Designates the block as a package with a namespace. Without block, applies to the remainder of the current block or file. Sets package variable $VERSION to version, if specified.

require version

Requires Perl to be at least this version. version can be numeric like 5.005 or 5.008001, or a v-string like v5.8.1.

require expr†

If expr is numeric, behaves like require version. Otherwise expr must be the name of a file that is included from the Perl library. Does not include more than once, and yields a fatal error if the file does not evaluate to true. If expr is a bare word, assumes extension .pm for the name of the file.

unimport module [ list ]

Usually cancels the effects of a previous import or use. Like import, unimport is not a built-in, but an ordinary class method.

use version

use pragma

See the section Pragmatic Modules below.

By convention, pragma names start with a lowercase letter.

use module [ version ] [ list ]

At compile time, requires the module, optionally verifies the version, and calls its import method on list.

If list is (), doesn’t call import.

Normally used to import a list of variables and subroutines from ...