Prelude.Unicode

If the Haddock documentation is unreadable, look the source.

This module adds unicode notation for some definitions in Prelude.

The following notations are built in GHC (enabled with the UnicodeSyntax language extension):

• '' ('\x2192') is equivalent to '->'.
• '' ('\x2190') is equivalent to '<-'.
• '' ('\x2237') is equivalent to '::'.
• '' ('\x21d2') is equivalent to '=>'.
• '' ('\x2200') is equivalent to forall (use the Rank2Types language extension).

The following notations are not built in GHC (see also http://hackage.haskell.org/trac/haskell-prime/wiki/UnicodeInHaskellSource):

• '' ('\x2025') is equivalent to '..'.
• '' ('\x2203') is equivalent to exists (with ExistentialQuantification).

Usage examples

 even  succ    Integral a  a  Bool 

 25  [xx | x[1..10], x2]    Bool

 foldl (flip (:)) ()    [a]  [a]

 (\a  a  a  a)    a  a : a : a

 (\a b  ()(a  b)  ()a  ()b)    Bool  Bool  Bool

Data structures

type :× a b = (a, b)

Pair.

(×) :: a -> b -> a :× b

Pair creation. It is not a constructor so can not be used in patterns.

Boolean functions and operators

(¬) :: Bool -> Bool

Boolean not.

(∧) :: Bool -> Bool -> Bool

Boolean and.

(∨) :: Bool -> Bool -> Bool

Boolean or.

(⇔) :: Bool -> Bool -> Bool

Boolean equality check.

Comparisons

(≡) :: Eq a => a -> a -> Bool

Equal.

(≠) :: Eq a => a -> a -> Bool

Not equal.

(≢) :: Eq a => a -> a -> Bool

Not equal.

(≤) :: Ord a => a -> a -> Bool

Less or equal.

(≥) :: Ord a => a -> a -> Bool

Greater or equal.

(≮) :: Ord a => a -> a -> Bool

Not less.

(≯) :: Ord a => a -> a -> Bool

Not greater.

Numbers

π :: Floating a => a

1. 1415..

(÷) :: Fractional a => a -> a -> a

Division.

· :: Num a => a -> a -> a

Multiplication.

Functions

(◦) :: (b -> c) -> (a -> b) -> a -> c

Function composition.

Lists

(∅) :: [a]

The empty list.

(∈) :: Eq a => a -> [a] -> Bool

The list membership predicate.

(∉) :: Eq a => a -> [a] -> Bool

The negation of the list membership predicate.

Misc

(⊥) :: a

Undefined value.