15 lines
444 B
Text
15 lines
444 B
Text
/-
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Copyright (c) 2017 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura
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-/
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prelude
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import init.category.monad init.data.string.basic
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universes u v
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class monad_fail (m : Type u → Type v) extends monad m :=
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(fail : Π {a}, string → m a)
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def match_failed {α : Type u} {m : Type u → Type v} [monad_fail m] : m α :=
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monad_fail.fail m "match failed"
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