/-
Copyright (c) 2016 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
-/
prelude
import init.data.fin.basic

open nat
def char_sz : nat := succ 255

def char := fin char_sz

instance : has_sizeof char :=
⟨fin.sizeof _⟩

namespace char
/- We cannot use tactic dec_trivial here because the tactic framework has not been defined yet. -/
lemma zero_lt_char_sz : 0 < char_sz :=
zero_lt_succ _

@[pattern] def of_nat (n : nat) : char :=
if h : n < char_sz then fin.mk n h else fin.mk 0 zero_lt_char_sz

def to_nat (c : char) : nat :=
fin.val c
end char

instance : decidable_eq char :=
have decidable_eq (fin char_sz), from fin.decidable_eq _,
this

instance : inhabited char :=
⟨'A'⟩
