lean2/hott/init/function.hlean
Floris van Doorn f513538631 feat(hott): more cleanup of HoTT library
remove funext class,
remove a couple of sorry's,
add characterization of equality in trunctypes,
use Jeremy's format for headers everywhere in the HoTT library,
continue working on Yoneda embedding
2015-02-26 13:19:54 -05:00

61 lines
1.6 KiB
Text

/-
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Module: init.function
Author: Leonardo de Moura
General operations on functions.
-/
prelude
import init.reserved_notation
namespace function
variables {A : Type} {B : Type} {C : Type} {D : Type} {E : Type}
definition compose [reducible] (f : B → C) (g : A → B) : A → C :=
λx, f (g x)
definition id [reducible] (a : A) : A :=
a
definition on_fun [reducible] (f : B → B → C) (g : A → B) : A → A → C :=
λx y, f (g x) (g y)
definition combine [reducible] (f : A → B → C) (op : C → D → E) (g : A → B → D) : A → B → E :=
λx y, op (f x y) (g x y)
definition const [reducible] (B : Type) (a : A) : B → A :=
λx, a
definition dcompose [reducible] {B : A → Type} {C : Π {x : A}, B x → Type}
(f : Π {x : A} (y : B x), C y) (g : Πx, B x) : Πx, C (g x) :=
λx, f (g x)
definition flip [reducible] {C : A → B → Type} (f : Πx y, C x y) : Πy x, C x y :=
λy x, f x y
definition app [reducible] {B : A → Type} (f : Πx, B x) (x : A) : B x :=
f x
precedence `∘'`:60
precedence `on`:1
precedence `$`:1
variables {f g : A → B}
infixr ∘ := compose
infixr ∘' := dcompose
infixl on := on_fun
infixr $ := app
notation f `-[` op `]-` g := combine f op g
-- Trick for using any binary function as infix operator
notation a `⟨` f `⟩` b := f a b
end function
-- copy reducible annotations to top-level
export [reduce-hints] function