34 lines
851 B
Text
34 lines
851 B
Text
/-
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Copyright (c) 2016 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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Author: Leonardo de Moura
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-/
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prelude
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import init.fin
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open nat
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definition char_sz : nat := succ 255
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definition char := fin char_sz
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namespace char
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/- We cannot use tactic dec_trivial here because the tactic framework has not been defined yet. -/
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private lemma zero_lt_char_sz : 0 < char_sz :=
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zero_lt_succ _
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attribute [pattern]
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definition of_nat (n : nat) : char :=
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if H : n < char_sz then fin.mk n H else fin.mk 0 zero_lt_char_sz
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definition to_nat (c : char) : nat :=
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fin.val c
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end char
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attribute [instance]
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definition char_has_decidable_eq : decidable_eq char :=
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have decidable_eq (fin char_sz), from fin.has_decidable_eq _,
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this
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attribute [instance]
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definition char_is_inhabited : inhabited char :=
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⟨'A'⟩
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