Context Managers in Python Post: 302954900

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Top Forums Shell Programming and Scripting Context Managers in Python Post 302954900 by Aia on Saturday 12th of September 2015 01:00:19 PM

09-12-2015

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A Context Manager is any class that must, at least, implement a __enter__() method and a __exit__() method. The purpose of this class is to setup, or build up an object and tear it down when you are done with it.
The __enter__() method would initialize the object, it would utilized the try, except and finally statements, and it would produce a proper return.
The __exit__() method would do the proper clean up after the object is not necessary any longer.

A common example of using a Context Manager is with opening files.
If you do it manually, you would have to do the checks necessary: that the file exists, that it can be accessed and opened, etc. After that you need to release the object file by closing it. This setup and tear-down action can be taken care of, nicely, using a Context Manager.

Last edited by Aia; 09-12-2015 at 08:57 PM..

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LEARN ABOUT MOJAVE

moosex::declare::context::namespaced

MooseX::Declare::Context::Namespaced(3pm)		User Contributed Perl Documentation		 MooseX::Declare::Context::Namespaced(3pm)

NAME

       MooseX::Declare::Context::Namespaced - Namespaced context

DESCRIPTION

       This context trait will add namespace functionality to the context.

ATTRIBUTES

   namespace
       This will be set when the "strip_namespace" method is called and the namespace wasn't anonymous. It will contain the specified namespace,
       not the fully qualified one.

METHODS

   strip_namespace
	 Maybe[Str] Object->strip_namespace()

       This method is intended to parse the main namespace of a namespaced keyword.  It will use Devel::Declare::Context::Simples "strip_word"
       method and store the result in the "namespace" attribute if true.

   qualify_namespace
	 Str Object->qualify_namespace(Str $namespace)

       If the $namespace passed it begins with a "::", it will be prefixed with the outer namespace in the file. If there is no outer namespace,
       an error will be thrown.

SEE ALSO

       o   MooseX::Declare

       o   MooseX::Declare::Context

AUTHOR

       Florian Ragwitz <rafl@debian.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2008 by Florian Ragwitz.

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

perl v5.18.2							    2013-12-14				 MooseX::Declare::Context::Namespaced(3pm)