a2abbdbf9a
This is just a draft. ``` for f in `find . -name '*.lean'`; do echo $f; gsed "/^import/s/\b\(.\)/\u\1/g" $f > tmp; gsed "/^Import/s/Import/import/g" tmp > $f; done ```
72 lines
1.7 KiB
Text
72 lines
1.7 KiB
Text
/-
|
||
Copyright (c) 2019 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.List.Basic
|
||
import Init.Util
|
||
|
||
universes u
|
||
|
||
namespace List
|
||
/- The following functions can't be defined at `init.data.list.basic`, because they depend on `init.util`,
|
||
and `init.util` depends on `init.data.list.basic`. -/
|
||
|
||
variables {α : Type u}
|
||
|
||
def get! [Inhabited α] : Nat → List α → α
|
||
| 0, a::as => a
|
||
| n+1, a::as => get! n as
|
||
| _, _ => panic! "invalid index"
|
||
|
||
def get? : Nat → List α → Option α
|
||
| 0, a::as => some a
|
||
| n+1, a::as => get? n as
|
||
| _, _ => none
|
||
|
||
def getD (idx : Nat) (as : List α) (a₀ : α) : α :=
|
||
(as.get? idx).getD a₀
|
||
|
||
def head! [Inhabited α] : List α → α
|
||
| [] => panic! "empty list"
|
||
| a::_ => a
|
||
|
||
def head? : List α → Option α
|
||
| [] => none
|
||
| a::_ => some a
|
||
|
||
def headD : List α → α → α
|
||
| [], a₀ => a₀
|
||
| a::_, _ => a
|
||
|
||
def tail! : List α → List α
|
||
| [] => panic! "empty list"
|
||
| a::as => as
|
||
|
||
def tail? : List α → Option (List α)
|
||
| [] => none
|
||
| a::as => some as
|
||
|
||
def tailD : List α → List α → List α
|
||
| [], as₀ => as₀
|
||
| a::as, _ => as
|
||
|
||
def getLast : ∀ (as : List α), as ≠ [] → α
|
||
| [], h => absurd rfl h
|
||
| [a], h => a
|
||
| a::b::as, h => getLast (b::as) (fun h => List.noConfusion h)
|
||
|
||
def getLast! [Inhabited α] : List α → α
|
||
| [] => panic! "empty list"
|
||
| a::as => getLast (a::as) (fun h => List.noConfusion h)
|
||
|
||
def getLast? : List α → Option α
|
||
| [] => none
|
||
| a::as => some (getLast (a::as) (fun h => List.noConfusion h))
|
||
|
||
def getLastD : List α → α → α
|
||
| [], a₀ => a₀
|
||
| a::as, _ => getLast (a::as) (fun h => List.noConfusion h)
|
||
|
||
end List
|