Version 21 of Haskell

Updated 2014-08-18 16:20:50 by pooryorick

Haskell is a polymorphicly-typed, type-safe, lazy, purely functional language.

See Also

Interfacing Tcl with Haskell

Monads

Playing Haskell

Tcl and other languages

FranTk

is a declarative GUI binding of Tk

Description

wdb: In Haskell it is not possible to assign a value to a variable. Therefore a program runs completely side-effect free.

Notation

'

surrounds a character

"

surrounds a sequence of characters, indicating a list composed of those characters in that sequence

(thing1,thing2)

"pair of things, each having its own type"

(type1,type2)

"pair of types"

(Tree a)

"a, which is of type Tree"

+

polymorphic infix operator for addition

++

polymorphic infix operator for concatenation

-

polymorphic infix operator for subtraction

->

(left) "maps to" (right)

.

infix operator for function composition

..

arithmetic sequence indicator

:

"is prepended to"

::

"has type"

<-

(left) "maps from" (right)

=>

"evaluates to", "reduces to"

=

"is defined as"

[]

"empty list"

[(a,b)]

"list where each thing is a pair of a thing having type a and a thing having type b"

[a]

"list of things which are of type a"

`

surrounds a function to indicate that it is being used as an infix operator

\

lambda function.

_|_

abstract notation for a non-terminating expression. Also known as "bottonm"

| (in a type declaration)

"or"

| (in a list comprehension)

"where"

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