{-# LANGUAGE NoImplicitPrelude, UnicodeSyntax #-}

{-|
Module     : PreludePlus.Unicode
Copyright  : 2018 Joshua Booth
License    : BSD3 (see the file LICENSE)
Maintainer : Joshua Booth <joshua.n.booth@gmail.com>

Various unicode synonyms for basic functions.
-}

module PreludePlus.Unicode
    ( -- * Functional
      (∘)
    , (↦)
    , (↤)
    , (↤∘)
    , (≫=)
    , (≫)
    , (=≪)
    -- * Boolean
    , (∨)
    , (∧)
    -- * Comparison
    , (≡)
    , (≠)
    , (≤)
    , (≥)
    -- * Arithmetic
    , (÷)
    , (٪)
    , (—)
    -- * Collections
    , (⌥)
    , (∈)
    , (∉)
    , (⧺)
    , (∪)
    , (∩)
    , (⩀)
    , (∖)
    , ø
    ) where

import Control.Applicative (Alternative, (<|>))
import Control.Monad       (Monad, (>>=), (>>), (=<<))
import Data.Bool           (Bool, (&&), (||), not)
import Data.Eq             (Eq, (==), (/=))
import Data.Foldable       (Foldable, elem, notElem)
import Data.Function       ((.), ($), flip)
import Data.Functor        (Functor, fmap)
import Data.Monoid         (Monoid, mempty)
import Data.List           ((\\), intersect, null, union)
import Data.Ord            (Ord, (<=), (>=))
import Data.Semigroup      (Semigroup, (<>))
import GHC.Num             (Num, (-))
import GHC.Real            (Integral, quot, mod)

------------
-- Functions
------------

-- | @(∘) = ('.')@
--
-- U+2218, RING OPERATOR
infixr 9 ∘
(∘) ∷ (b → g) → (a → b) → (a → g)
(∘) = (.)
{-# INLINE (∘) #-}

-- | @(↦) = 'flip' 'fmap'@
--
-- U+21A6, RIGHTWARDS ARROW FROM BAR
infixl 4 ↦
(↦) ∷ Functor f => f a → (a → b) → f b
(↦) = flip fmap
{-# INLINE (↦) #-}

-- | @(↤) = 'fmap'@
--
-- U+21A4, LEFTWARDS ARROW FROM BAR
infixl 4 ↤
(↤) ∷ Functor f => (a → b) → f a → f b
(↤) = fmap
{-# INLINE (↤) #-}

-- | @f ↤∘ g = 'fmap' f ∘ g@
--
-- (U+21A4, LEFTWARDS ARROW FROM BAR) + (U+2218, RING OPERATOR)
infixr 7 ↤∘
(↤∘) ∷ Functor f => (a → b) → (c → f a) → c → f b
f ↤∘ g = fmap f ∘ g

-- | @(≫=) = ('>>=')@
--
-- (U+226B, MUCH GREATER-THAN) + (U+003D, EQUALS SIGN)
infixl 1 ≫=
(≫=) ∷ Monad m => m a → (a → m b) → m b
(≫=) = (>>=)
{-# INLINE (≫=) #-}

-- | @(≫) = ('>>')@
--
-- U+226B, MUCH GREATER-THAN
infixl 1 ≫
(≫) ∷ Monad m => m a → m b → m b
(≫) = (>>)
{-# INLINE (≫) #-}

-- | @(=≪) = ('=<<')@
--
-- (U+003D, EQUALS SIGN) + (U+226A, MUCH LESS-THAN)
infixr 1 =≪
(=≪) ∷ Monad m => (a → m b) → m a → m b
(=≪) = (=<<)
{-# INLINE (=≪) #-}

----------
-- Boolean
----------

-- | @(∨) = ('||')@
--
-- U+2228, LOGICAL OR
infixr 2 ∨
(∨) ∷ Bool → Bool → Bool
(∨) = (||)
{-# INLINE (∨) #-}

-- | @(∧) = ('&&')@
--
-- U+2227, LOGICAL AND
infixr 3 ∧
(∧) ∷ Bool → Bool → Bool
(∧) = (&&)
{-# INLINE (∧) #-}

-------------
-- Comparison
-------------

-- | @(≡) = ('==')@
--
-- U+2261, IDENTICAL TO
infix  4 ≡
(≡) ∷ Eq a => a → a → Bool
(≡) = (==)
{-# INLINE (≡) #-}

-- | @(≠) = ('/=')@
--
-- U+2260, NOT EQUAL TO
infix  4 ≠
(≠) ∷ Eq a => a → a → Bool
(≠) = (/=)
{-# INLINE (≠) #-}

-- | @(≤) = ('<=')@
--
-- U+2264, LESS-THAN OR EQUAL TO
infix  4 ≤
(≤) ∷ Ord a => a → a → Bool
(≤) = (<=)
{-# INLINE (≤) #-}

-- | @(≥) = ('>=')@
--
-- U+2265, GREATER-THAN OR EQUAL TO
infix  4 ≥
(≥) ∷ Ord a => a → a → Bool
(≥) = (>=)
{-# INLINE (≥) #-}

-------------
-- Arithmetic
-------------

-- | @(÷) = 'quot'@
--
-- U+00F7, DIVISION SIGN
infixl 7 ÷
(÷) ∷ Integral a => a → a → a
(÷) = quot
{-# INLINE (÷) #-}

-- | @(٪) = 'mod'@
--
-- U+066A, ARABIC PERCENT SIGN
infixl 7 ٪
(٪) ∷ Integral a => a → a → a
(٪) = mod
{-# INLINE (٪) #-}

-- | @(—) = ('-')@
--
-- U+2014, EM DASH
--
-- Allows for sections, as in @(—3)@.
(—) ∷ Num a => a → a → a
(—) = (-) 

--------------
-- Collections
--------------

-- | @(⌥) = ('<|>')@
--
-- U+2325, OPTION KEY
(⌥) ∷ Alternative f => f a → f a → f a
(⌥) = (<|>)

-- | @(∈) = 'elem'@
--
-- U+2208, ELEMENT OF
infix  4 ∈
(∈) ∷ (Foldable a, Eq b) => b → a b → Bool
(∈) = elem
{-# INLINE (∈) #-}

-- | @(∉) = 'notElem'@
--
-- U+2209, NOT AN ELEMENT OF
infix 4 ∉
(∉) ∷ (Foldable a, Eq b) => b → a b → Bool
(∉) = notElem
{-# INLINE (∉) #-}

-- | @(⧺) = ('<>')@
--
-- U+29FA, DOUBLE PLUS
infixr 5 ⧺
(⧺) ∷ Semigroup m => m → m → m
(⧺) = (<>)
{-# INLINE (⧺) #-}

-- | @(∖) = ('\\')@
--
-- U+2216, SET MINUS
infixr 5 ∖
(∖) ∷ Eq a => [a] → [a] → [a]
(∖) = (\\)

-- | @(∪) = 'union'@
--
-- U+22A, UNION
infixl 6 ∪
(∪) ∷ Eq a => [a] → [a] → [a]
(∪) = union
{-# INLINE (∪) #-}

-- | @(∩) = 'intersect'@
--
-- U+2229, INTERSECTION
infixr 6 ∩
(∩) ∷ Eq a => [a] → [a] → [a]
(∩) = intersect

-- | @(⩀) a b = 'not' ∘ 'null' $ 'intersect' a b@
--
-- U+2A40, INTERSECTION WITH DOT
infixr 6 ⩀
(⩀) ∷ Eq a => [a] → [a] → Bool
(⩀) a b = not ∘ null $ intersect a b

-- | @ø = 'mempty'@
--
-- U+00F8, LATIN SMALL LETTER O WITH STROKE
ø ∷ Monoid a => a
ø = mempty