92 lines
2.4 KiB
Text
92 lines
2.4 KiB
Text
/-
|
||
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.uint
|
||
@[inline, reducible] def is_valid_char (n : uint32) : Prop :=
|
||
n < 0xd800 ∨ (0xdfff < n ∧ n < 0x110000)
|
||
|
||
/-- The `char` type represents an unicode scalar value.
|
||
See http://www.unicode.org/glossary/#unicode_scalar_value). -/
|
||
structure char :=
|
||
(val : uint32) (valid : is_valid_char val)
|
||
|
||
instance : has_sizeof char :=
|
||
⟨λ c, c.val.to_nat⟩
|
||
|
||
namespace char
|
||
local infix `&`:65 := uint32.land
|
||
|
||
def utf8_size (c : char) : uint32 :=
|
||
let v := c.val in
|
||
if v & 0x80 = 0 then 1
|
||
else if v & 0xE0 = 0xC0 then 2
|
||
else if v & 0xF0 = 0xE0 then 3
|
||
else if v & 0xF8 = 0xF0 then 4
|
||
else if v & 0xFC = 0xF8 then 5
|
||
else if v & 0xFE = 0xFC then 6
|
||
else if v = 0xFF then 1
|
||
else 0
|
||
|
||
protected def lt (a b : char) : Prop := a.val < b.val
|
||
protected def le (a b : char) : Prop := a.val ≤ b.val
|
||
|
||
instance : has_lt char := ⟨char.lt⟩
|
||
instance : has_le char := ⟨char.le⟩
|
||
|
||
instance dec_lt (a b : char) : decidable (a < b) :=
|
||
uint32.dec_lt _ _
|
||
|
||
instance dec_le (a b : char) : decidable (a ≤ b) :=
|
||
uint32.dec_le _ _
|
||
|
||
@[noinline, pattern] def of_nat (n : nat) : char :=
|
||
if h : is_valid_char (uint32.of_nat n) then {val := uint32.of_nat n, valid := h} else {val := 0, valid := sorry}
|
||
|
||
@[inline] def to_nat (c : char) : nat :=
|
||
c.val.to_nat
|
||
|
||
lemma eq_of_veq : ∀ {c d : char}, c.val = d.val → c = d
|
||
| ⟨v, h⟩ ⟨_, _⟩ rfl := rfl
|
||
|
||
lemma veq_of_eq : ∀ {c d : char}, c = d → c.val = d.val
|
||
| _ _ rfl := rfl
|
||
|
||
lemma ne_of_vne {c d : char} (h : c.val ≠ d.val) : c ≠ d :=
|
||
λ h', absurd (veq_of_eq h') h
|
||
|
||
lemma vne_of_ne {c d : char} (h : c ≠ d) : c.val ≠ d.val :=
|
||
λ h', absurd (eq_of_veq h') h
|
||
|
||
instance : decidable_eq char :=
|
||
{dec_eq := λ i j, decidable_of_decidable_of_iff
|
||
(dec_eq i.val j.val) ⟨char.eq_of_veq, char.veq_of_eq⟩}
|
||
|
||
instance : inhabited char :=
|
||
⟨'A'⟩
|
||
|
||
def is_whitespace (c : char) : bool :=
|
||
c = ' ' || c = '\t' || c = '\n'
|
||
|
||
def is_upper (c : char) : bool :=
|
||
c.val ≥ 65 && c.val ≤ 90
|
||
|
||
def is_lower (c : char) : bool :=
|
||
c.val ≥ 97 && c.val ≤ 122
|
||
|
||
def is_alpha (c : char) : bool :=
|
||
c.is_upper || c.is_lower
|
||
|
||
def is_digit (c : char) : bool :=
|
||
c.val ≥ 48 && c.val ≤ 57
|
||
|
||
def is_alphanum (c : char) : bool :=
|
||
c.is_alpha || c.is_digit
|
||
|
||
def to_lower (c : char) : char :=
|
||
let n := to_nat c in
|
||
if n >= 65 ∧ n <= 90 then of_nat (n + 32) else c
|
||
|
||
end char
|