120 lines
4.1 KiB
Text
120 lines
4.1 KiB
Text
/-
|
||
Copyright (c) 2020 Microsoft Corporation. All rights reserved.
|
||
Released under Apache 2.0 license as described in the file LICENSE.
|
||
Authors: Leonardo de Moura
|
||
-/
|
||
prelude
|
||
import Init.Data.Array.Basic
|
||
|
||
universes u v w
|
||
|
||
structure Subarray (α : Type u) where
|
||
as : Array α
|
||
start : Nat
|
||
stop : Nat
|
||
h₁ : start ≤ stop
|
||
h₂ : stop ≤ as.size
|
||
|
||
namespace Subarray
|
||
|
||
@[inline] unsafe def forInUnsafe {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (s : Subarray α) (b : β) (f : α → β → m (ForInStep β)) : m β :=
|
||
let sz := USize.ofNat s.stop
|
||
let rec @[specialize] loop (i : USize) (b : β) : m β := do
|
||
if i < sz then
|
||
let a := s.as.uget i lcProof
|
||
match (← f a b) with
|
||
| ForInStep.done b => pure b
|
||
| ForInStep.yield b => loop (i+1) b
|
||
else
|
||
pure b
|
||
loop (USize.ofNat s.start) b
|
||
|
||
-- TODO: provide reference implementation
|
||
@[implementedBy Subarray.forInUnsafe]
|
||
constant forIn {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (s : Subarray α) (b : β) (f : α → β → m (ForInStep β)) : m β :=
|
||
pure b
|
||
|
||
@[inline]
|
||
def foldlM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : β → α → m β) (init : β) (as : Subarray α) : m β :=
|
||
as.as.foldlM f (init := init) (start := as.start) (stop := as.stop)
|
||
|
||
@[inline]
|
||
def foldrM {α : Type u} {β : Type v} {m : Type v → Type w} [Monad m] (f : α → β → m β) (init : β) (as : Subarray α) : m β :=
|
||
as.as.foldrM f (init := init) (start := as.stop) (stop := as.start)
|
||
|
||
@[inline]
|
||
def anyM {α : Type u} {m : Type → Type w} [Monad m] (p : α → m Bool) (as : Subarray α) : m Bool :=
|
||
as.as.anyM p (start := as.start) (stop := as.stop)
|
||
|
||
@[inline]
|
||
def allM {α : Type u} {m : Type → Type w} [Monad m] (p : α → m Bool) (as : Subarray α) : m Bool :=
|
||
as.as.allM p (start := as.start) (stop := as.stop)
|
||
|
||
@[inline]
|
||
def forM {α : Type u} {m : Type v → Type w} [Monad m] (f : α → m PUnit) (as : Subarray α) : m PUnit :=
|
||
as.as.forM f (start := as.start) (stop := as.stop)
|
||
|
||
@[inline]
|
||
def forRevM {α : Type u} {m : Type v → Type w} [Monad m] (f : α → m PUnit) (as : Subarray α) : m PUnit :=
|
||
as.as.forRevM f (start := as.stop) (stop := as.start)
|
||
|
||
@[inline]
|
||
def foldl {α : Type u} {β : Type v} (f : β → α → β) (init : β) (as : Subarray α) : β :=
|
||
Id.run <| as.foldlM f (init := init)
|
||
|
||
@[inline]
|
||
def foldr {α : Type u} {β : Type v} (f : α → β → β) (init : β) (as : Subarray α) : β :=
|
||
Id.run <| as.foldrM f (init := init)
|
||
|
||
@[inline]
|
||
def any {α : Type u} (p : α → Bool) (as : Subarray α) : Bool :=
|
||
Id.run <| as.anyM p
|
||
|
||
@[inline]
|
||
def all {α : Type u} (p : α → Bool) (as : Subarray α) : Bool :=
|
||
Id.run <| as.allM p
|
||
|
||
end Subarray
|
||
|
||
namespace Array
|
||
variable {α : Type u}
|
||
|
||
def toSubarray (as : Array α) (start stop : Nat) : Subarray α :=
|
||
if h₂ : stop ≤ as.size then
|
||
if h₁ : start ≤ stop then
|
||
{ as := as, start := start, stop := stop, h₁ := h₁, h₂ := h₂ }
|
||
else
|
||
{ as := as, start := stop, stop := stop, h₁ := Nat.leRefl _, h₂ := h₂ }
|
||
else
|
||
if h₁ : start ≤ as.size then
|
||
{ as := as, start := start, stop := as.size, h₁ := h₁, h₂ := Nat.leRefl _ }
|
||
else
|
||
{ as := as, start := as.size, stop := as.size, h₁ := Nat.leRefl _, h₂ := Nat.leRefl _ }
|
||
|
||
def ofSubarray (s : Subarray α) : Array α := do
|
||
let mut as := mkEmpty (s.stop - s.start)
|
||
for a in s do
|
||
as := as.push a
|
||
return as
|
||
|
||
def extract (as : Array α) (start stop : Nat) : Array α :=
|
||
ofSubarray (as.toSubarray start stop)
|
||
|
||
instance : Coe (Subarray α) (Array α) := ⟨ofSubarray⟩
|
||
|
||
syntax:max term noWs "[" term ":" term "]" : term
|
||
syntax:max term noWs "[" term ":" "]" : term
|
||
syntax:max term noWs "[" ":" term "]" : term
|
||
|
||
macro_rules
|
||
| `($a[$start : $stop]) => `(Array.toSubarray $a $start $stop)
|
||
| `($a[ : $stop]) => `(Array.toSubarray $a 0 $stop)
|
||
| `($a[$start : ]) => `(let a := $a; Array.toSubarray a $start a.size)
|
||
|
||
end Array
|
||
|
||
def Subarray.toArray (s : Subarray α) : Array α :=
|
||
Array.ofSubarray s
|
||
|
||
instance : HAppend (Subarray α) (Subarray α) (Array α) where
|
||
hAppend x y := x.toArray ++ y.toArray
|