{-# LANGUAGE NoImplicitPrelude, UnicodeSyntax #-}

module Data.List.Unicode
    ( (⧺)
    , (∈), (∋), (∉), (∌)
    , (∪), (∖), (∆), (∩)
    , (‼)
    , 𝜀
    ) where

-------------------------------------------------------------------------------
-- Imports
-------------------------------------------------------------------------------

-- from base:
import Prelude       ( Int )
import Data.Bool     ( Bool )
import Data.Eq       ( Eq )
import Data.Function ( flip )
import Data.List     ( (++), elem, notElem, union, (\\), intersect, (!!) )


-------------------------------------------------------------------------------
-- Fixities
-------------------------------------------------------------------------------

infix  4 ∈
infix  4 ∋
infix  4 ∉
infix  4 ∌
infixr 5 ⧺
infixl 6 ∪
infixr 6 ∩
infixl 9 ∖
infixl 9 ∆
infixl 9 ‼


-------------------------------------------------------------------------------
-- Symbols
-------------------------------------------------------------------------------

{-|
(⧺) = ('++')

U+29FA, DOUBLE PLUS
-}
(⧺) ∷ [α] → [α] → [α]
⧺ :: forall α. [α] -> [α] -> [α]
(⧺) = [α] -> [α] -> [α]
forall α. [α] -> [α] -> [α]
(++)
{-# INLINE (⧺) #-}

{-|
(∈) = 'elem'

U+2208, ELEMENT OF
-}
(∈) ∷ Eq α ⇒ α → [α] → Bool
∈ :: forall α. Eq α => α -> [α] -> Bool
(∈) = α -> [α] -> Bool
forall α. Eq α => α -> [α] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
elem
{-# INLINE (∈) #-}

{-|
(∋) = 'flip' (∈)

U+220B, CONTAINS AS MEMBER
-}
(∋) ∷ Eq α ⇒ [α] → α → Bool
∋ :: forall α. Eq α => [α] -> α -> Bool
(∋) = (α -> [α] -> Bool) -> [α] -> α -> Bool
forall a b c. (a -> b -> c) -> b -> a -> c
flip α -> [α] -> Bool
forall α. Eq α => α -> [α] -> Bool
(∈)
{-# INLINE (∋) #-}

{-|
(∉) = 'notElem'

U+2209, NOT AN ELEMENT OF
-}
(∉) ∷ Eq α ⇒ α → [α] → Bool
∉ :: forall α. Eq α => α -> [α] -> Bool
(∉) = α -> [α] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
notElem
{-# INLINE (∉) #-}

{-|
(∌) = 'flip' (∉)

U+220C, DOES NOT CONTAIN AS MEMBER
-}
(∌) ∷ Eq α ⇒ [α] → α → Bool
∌ :: forall α. Eq α => [α] -> α -> Bool
(∌) = (α -> [α] -> Bool) -> [α] -> α -> Bool
forall a b c. (a -> b -> c) -> b -> a -> c
flip α -> [α] -> Bool
forall α. Eq α => α -> [α] -> Bool
(∉)
{-# INLINE (∌) #-}

{-|
(∪) = 'union'

U+222A, UNION
-}
(∪) ∷ Eq α ⇒ [α] → [α] → [α]
∪ :: forall α. Eq α => [α] -> [α] -> [α]
(∪) = [α] -> [α] -> [α]
forall α. Eq α => [α] -> [α] -> [α]
union
{-# INLINE (∪) #-}

{-|
(∖) = ('\\')

U+2216, SET MINUS
-}
(∖) ∷ Eq α ⇒ [α] → [α] → [α]
∖ :: forall α. Eq α => [α] -> [α] -> [α]
(∖) = [α] -> [α] -> [α]
forall α. Eq α => [α] -> [α] -> [α]
(\\)
{-# INLINE (∖) #-}

{-|
Symmetric difference

a ∆ b = (a ∖ b) ∪ (b ∖ a)

U+2206, INCREMENT
-}
(∆) ∷ Eq α ⇒ [α] → [α] → [α]
[α]
a ∆ :: forall α. Eq α => [α] -> [α] -> [α]
∆ [α]
b = ([α]
a [α] -> [α] -> [α]
forall α. Eq α => [α] -> [α] -> [α]
∖ [α]
b) [α] -> [α] -> [α]
forall α. Eq α => [α] -> [α] -> [α]
∪ ([α]
b [α] -> [α] -> [α]
forall α. Eq α => [α] -> [α] -> [α]
∖ [α]
a)
{-# INLINE (∆) #-}

{-|
(∩) = 'intersect'

U+2229, INTERSECTION
-}
(∩) ∷ Eq α ⇒ [α] → [α] → [α]
∩ :: forall α. Eq α => [α] -> [α] -> [α]
(∩) = [α] -> [α] -> [α]
forall α. Eq α => [α] -> [α] -> [α]
intersect
{-# INLINE (∩) #-}

{-|
(‼) = ('!!')

U+203C, DOUBLE EXCLAMATION MARK
-}
(‼) ∷ [α] → Int → α
‼ :: forall α. [α] -> Int -> α
(‼) = [α] -> Int -> α
forall a. HasCallStack => [a] -> Int -> a
(!!)
{-# INLINE (‼) #-}

{-|
Epsilon, the empty word (or list)

(ε) = []

(U+3B5, GREEK SMALL LETTER EPSILON)
-}
𝜀 ∷ [a]
𝜀 :: forall a. [a]
𝜀 = []