Data.Restricted

Type-level restricted data. This module allows for type declarations which embed certain restrictions, such as value bounds. E.g. Restricted N0 N1 Int denotes an Int which can only have values [0 .. 1]. When creating such a value, the constructor functions restrict or toRestricted ensure that the restrictions are obeyed. Code that consumes restricted types does not need to check the constraints.

N.B. This module is more or less tailored to be used within ZMQ3. Therefore the provided type level restrictions are limited.

Documentation

data Restricted r v

Type level restriction.

Instances

Show v => Show (Restricted r v)

class Restriction r v where

A uniform way to restrict values.

Methods

toRestricted :: v -> Maybe (Restricted r v)

Create a restricted value. Returns Nothing if the given value does not satisfy all restrictions.

restrict :: v -> Restricted r v

Create a restricted value. If the given value does not satisfy the restrictions, a modified variant is used instead, e.g. if an integer is larger than the upper bound, the upper bound value is used.

Instances

Restriction Div5 ByteString

Restriction Div4 ByteString

Integral a => Restriction (N1, Int32) a

Integral a => Restriction (N1, Int64) a

Integral a => Restriction (N1, Inf) a

Restriction (N1, N254) String

Restriction (N1, N254) ByteString

Integral a => Restriction (N0, Int32) a

Integral a => Restriction (N0, Int64) a

Integral a => Restriction (N0, Inf) a

Integral a => Restriction (Nneg1, Int32) a

Integral a => Restriction (Nneg1, Int64) a

Integral a => Restriction (Nneg1, Inf) a

rvalue :: Restricted r v -> v

Get the actual value.

data Nneg1

type level -1

Instances

Show Nneg1

Integral a => Restriction (Nneg1, Int32) a

Integral a => Restriction (Nneg1, Int64) a

Integral a => Restriction (Nneg1, Inf) a

data N1

type-level 1

Instances

Show N1

Integral a => Restriction (N1, Int32) a

Integral a => Restriction (N1, Int64) a

Integral a => Restriction (N1, Inf) a

Restriction (N1, N254) String

Restriction (N1, N254) ByteString

data N0

type-level 0

Instances

Show N0

Integral a => Restriction (N0, Int32) a

Integral a => Restriction (N0, Int64) a

Integral a => Restriction (N0, Inf) a

data N254

type-level 254

Instances

Show N254

Restriction (N1, N254) String

Restriction (N1, N254) ByteString

data Inf

type-level infinity

Instances

Show Inf

Integral a => Restriction (N1, Inf) a

Integral a => Restriction (N0, Inf) a

Integral a => Restriction (Nneg1, Inf) a

data Div4

divisable by 4

Instances

Show Div4

Restriction Div4 ByteString

data Div5

divisable by 5

Instances

Show Div5

Restriction Div5 ByteString