lean2/library/standard/data/option.lean

------------------------------------------------------------------------------------------------------ Copyright (c) 2014 Microsoft Corporation. All rights reserved.
-- Released under Apache 2.0 license as described in the file LICENSE.
-- Author: Leonardo de Moura
----------------------------------------------------------------------------------------------------

import logic.classes.inhabited

inductive option (A : Type) : Type :=
| none {} : option A
| some    : A → option A

theorem inhabited_option [instance] (A : Type) : inhabited (option A) :=
inhabited_intro none
refactor(library/standard): organize files into a hierarchy 2014-08-01 01:40:09 +00:00			`------------------------------------------------------------------------------------------------------ Copyright (c) 2014 Microsoft Corporation. All rights reserved.`
chore(library/standard): add copyright to library files Signed-off-by: Leonardo de Moura <leonardo@microsoft.com> 2014-06-30 18:44:47 +00:00			`-- Released under Apache 2.0 license as described in the file LICENSE.`
			`-- Author: Leonardo de Moura`
refactor(library/standard): organize files into a hierarchy 2014-08-01 01:40:09 +00:00			`----------------------------------------------------------------------------------------------------`

			`import logic.classes.inhabited`
feat(library/standard): add inhabited, and files option and unit Signed-off-by: Leonardo de Moura <leonardo@microsoft.com> 2014-06-30 02:30:38 +00:00
			`inductive option (A : Type) : Type :=`
			`\| none {} : option A`
			`\| some : A → option A`

refactor(library/standard): use new coding style, rename bool.b0 and bool.b1 to bool.ff and bool.tt Signed-off-by: Leonardo de Moura <leonardo@microsoft.com> 2014-07-29 02:58:57 +00:00			`theorem inhabited_option [instance] (A : Type) : inhabited (option A) :=`
			`inhabited_intro none`