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85 lines
1.9 KiB
Text
85 lines
1.9 KiB
Text
module [
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Task,
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succeed,
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fail,
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await,
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map,
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onFail,
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attempt,
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result,
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fromResult,
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loop,
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]
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import pf.Effect
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Task ok err : Effect.Effect (Result ok err)
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loop : state, (state -> Task [Step state, Done done] err) -> Task done err
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loop = \state, step ->
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looper = \current ->
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step current
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|> Effect.map
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\res ->
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when res is
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Ok (Step newState) -> Step newState
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Ok (Done res2) -> Done (Ok res2)
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Err e -> Done (Err e)
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Effect.loop state looper
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succeed : val -> Task val *
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succeed = \val ->
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Effect.always (Ok val)
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fail : err -> Task * err
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fail = \val ->
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Effect.always (Err val)
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fromResult : Result a e -> Task a e
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fromResult = \res ->
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when res is
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Ok a -> succeed a
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Err e -> fail e
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attempt : Task a b, (Result a b -> Task c d) -> Task c d
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attempt = \effect, transform ->
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Effect.after
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effect
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\res ->
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when res is
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Ok ok -> transform (Ok ok)
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Err err -> transform (Err err)
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await : Task a err, (a -> Task b err) -> Task b err
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await = \effect, transform ->
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Effect.after
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effect
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\res ->
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when res is
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Ok a -> transform a
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Err err -> Task.fail err
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onFail : Task ok a, (a -> Task ok b) -> Task ok b
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onFail = \effect, transform ->
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Effect.after
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effect
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\res ->
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when res is
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Ok a -> Task.succeed a
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Err err -> transform err
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map : Task a err, (a -> b) -> Task b err
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map = \effect, transform ->
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Effect.after
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effect
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\res ->
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when res is
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Ok a -> Task.succeed (transform a)
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Err err -> Task.fail err
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result : Task ok err -> Task (Result ok err) *
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result = \effect ->
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Effect.after
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effect
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\res -> Task.succeed res
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