IdrisDoc: Prelude.Basics

# Prelude.Basics

the : (a : Type) -> (value : a) -> a

  Manually assign a type to an expression.

  a

    the type to assign

  value

    the element to get the type

snd : ( a, b) -> b

  Return the second element of a pair.

id : a -> a

  Identity function.

fst : ( a, b) -> a

  Return the first element of a pair.

flip : (f : a -> b -> c) -> b -> a -> c

  Takes in the first two arguments in reverse order.

  f

    the function to flip

const : a -> b -> a

  Constant function. Ignores its second argument.

cong : (a = b) -> f a = f b

  Equality is a congruence.

apply : (a -> b) -> a -> b

  Function application.

Not : Type -> Type
data Dec : Type -> Type

  Decidability. A decidable property either holds or is a contradiction.

  Yes : (prf : prop) -> Dec prop

    The case where the property holds

    prf

      the proof

  No : (contra : prop -> Void) -> Dec prop

    The case where the property holding would be a contradiction

    contra

      a demonstration that prop would be a contradiction

(.) : (b -> c) -> (a -> b) -> a -> c

  Function composition

  Fixity
    Left associative, precedence 9