DA.Action

Reference documentation for Daml module DA.Action.

DA.Action

Action

Module Snapshot

Lifecycle

Stable.

Notices

Status: active Introduced in: 3.4.9 Removed in: - Warnings: 0 Deprecations: 0 Deprecated since: -

Functions

when

when : Applicative f => Bool -> f () -> f ()

Conditional execution of Action expressions. For example,

  when final (archive contractId)

will archive the contract contractId if the Boolean value final is True, and otherwise do nothing.

This function has short-circuiting semantics, i.e., when both arguments are present and the first arguments evaluates to False, the second argument is not evaluated at all.

unless

unless : Applicative f => Bool -> f () -> f ()

The reverse of when.

This function has short-circuiting semantics, i.e., when both arguments are present and the first arguments evaluates to True, the second argument is not evaluated at all.

foldrA

foldrA : Action m => (a -> b -> m b) -> b -> [a] -> m b

The foldrA is analogous to foldr, except that its result is encapsulated in an action. Note that foldrA works from right-to-left over the list arguments.

foldr1A

foldr1A : Action m => (a -> a -> m a) -> [a] -> m a

foldr1A is like foldrA but raises an error when presented with an empty list argument.

foldlA

foldlA : Action m => (b -> a -> m b) -> b -> [a] -> m b

foldlA is analogous to foldl, except that its result is encapsulated in an action. Note that foldlA works from left-to-right over the list arguments.

foldl1A

foldl1A : Action m => (a -> a -> m a) -> [a] -> m a

The foldl1A is like foldlA but raises an errors when presented with an empty list argument.

filterA

filterA : Applicative m => (a -> m Bool) -> [a] -> m [a]

Filters the list using the applicative function: keeps only the elements where the predicate holds. Example: given a collection of Iou contract IDs one can find only the GBPs.

filterA (fmap (\iou -> iou.currency == "GBP") . fetch) iouCids

replicateA

replicateA : Applicative m => Int -> m a -> m [a]

replicateA n act performs the action n times, gathering the results.

replicateA_

replicateA_ : Applicative m => Int -> m a -> m ()

Like replicateA, but discards the result.

>=>

>=> : Action m => (a -> m b) -> (b -> m c) -> a -> m c

Left-to-right composition of Kleisli arrows.

<=<

<=< : Action m => (b -> m c) -> (a -> m b) -> a -> m c

Right-to-left composition of Kleisli arrows. @(’>=>’)@, with the arguments flipped.