mirror of
https://github.com/roc-lang/roc.git
synced 2025-09-27 05:49:08 +00:00
46 lines
1.2 KiB
Text
46 lines
1.2 KiB
Text
interface Task
|
|
exposes [ Task, succeed, fail, after, map, putLine, getInt ]
|
|
imports [ Effect ]
|
|
|
|
|
|
Task ok err : Effect.Effect (Result ok err)
|
|
|
|
|
|
succeed : val -> Task val *
|
|
succeed = \val ->
|
|
Effect.always (Ok val)
|
|
|
|
|
|
fail : err -> Task * err
|
|
fail = \val ->
|
|
Effect.always (Err val)
|
|
|
|
after : Task a err, (a -> Task b err) -> Task b err
|
|
after = \effect, transform ->
|
|
Effect.after effect \result ->
|
|
when result is
|
|
Ok a -> transform a
|
|
Err err -> Task.fail err
|
|
|
|
map : Task a err, (a -> b) -> Task b err
|
|
map = \effect, transform ->
|
|
Effect.after effect \result ->
|
|
when result is
|
|
Ok a -> Task.succeed (transform a)
|
|
Err err -> Effect.always (Err err) # Task.fail err does not work. WEIRD!
|
|
|
|
putLine : Str -> Task {} *
|
|
putLine = \line -> Effect.map (Effect.putLine line) (\_ -> Ok {})
|
|
|
|
getInt : Task I64 []
|
|
getInt =
|
|
Effect.after Effect.getInt \{ isError, value, errorCode } ->
|
|
when isError is
|
|
True ->
|
|
when errorCode is
|
|
# A -> Task.fail InvalidCharacter
|
|
# B -> Task.fail IOError
|
|
_ -> Task.succeed -1
|
|
|
|
False ->
|
|
Task.succeed value
|