lean2/library/standard/option.lean
Leonardo de Moura 105c29b51e 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>
2014-07-28 19:59:38 -07:00

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-- 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
inductive option (A : Type) : Type :=
| none {} : option A
| some : A → option A
theorem inhabited_option [instance] (A : Type) : inhabited (option A) :=
inhabited_intro none