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Pipeline.elm
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Pipeline.elm
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module Pipeline exposing (custom, decode, hardcoded, list, listCustom, required)
import Bytes.Decode as Decode exposing (Decoder, Step(..), loop, map)
custom : Decoder a -> Decoder (a -> b) -> Decoder b
custom decoder wrapped =
Decode.map2 (<|) wrapped decoder
decode : a -> Decoder a
decode =
Decode.succeed
required : Decoder a -> Decoder (a -> b) -> Decoder b
required valDecoder decoder =
custom valDecoder decoder
list : Int -> Decoder a -> Decoder (List a)
list len decoder =
loop ( len, [] ) (listStep decoder)
listStep : Decoder a -> ( Int, List a ) -> Decoder (Step ( Int, List a ) (List a))
listStep decoder ( n, xs ) =
if n <= 0 then
Decode.succeed (Done xs)
else
map (\x -> Loop ( n - 1, x :: xs )) decoder
listCustom : List a -> (a -> Decoder b) -> Decoder (List b)
listCustom lens decoder =
loop ( lens, [] ) (listStepCustom decoder)
listStepCustom : (a -> Decoder b) -> ( List a, List b ) -> Decoder (Step ( List a, List b ) (List b))
listStepCustom decoder ( ls, xs ) =
case ls of
[] ->
Decode.succeed (Done xs)
l :: ls2 ->
map (\x -> Loop ( ls2, x :: xs )) (decoder l)
hardcoded : a -> Decoder (a -> b) -> Decoder b
hardcoded =
Decode.succeed >> custom