Module DA.Set¶

Note: This is only supported in DAML-LF 1.11 or later.

This module exports the generic set type Set k and associated functions. This module should be imported qualified, for example:

import DA.Set (Set)
import DA.Set qualified as S

This will give access to the Set type, and the various operations as S.lookup, S.insert, S.fromList, etc.

Set k internally uses the built-in order for the type k. This means that keys that contain functions are not comparable and will result in runtime errors. To prevent this, the Ord k instance is required for most set operations. It is recommended to only use Set k for key types that have an Ord k instance that is derived automatically using deriving:

data K = ...
  deriving (Eq, Ord)

This includes all built-in types that aren’t function types, such as Int, Text, Bool, (a, b) assuming a and b have default Ord instances, Optional t and [t] assuming t has a default Ord instance, Map k v assuming k and v have default Ord instances, and Set k assuming k has a default Ord instance.

Data Types¶

data Set k

The type of a set. This is a wrapper over the Map type.

Set

Field Type Description

map Map k ()

instance Ord k => Monoid (Set k)

instance Ord k => Semigroup (Set k)

instance IsParties (Set Party)

instance Ord k => Eq (Set k)

instance Ord k => Ord (Set k)

instance (Ord k, Show k) => Show (Set k)