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authorJakub Hampl <kopomir@gmail.com>2019-02-14 15:23:49 +0000
committerGitHub <noreply@github.com>2019-02-14 15:23:49 +0000
commit6bd5f8ccbd8c44c3311ef36b0e2de9ede4fa71ed (patch)
treede40a36d34cb734c2765a705506436f8b38e28a9 /style-generator/src/Decoder/Generic.elm
parentf0c36a3d49fad46e0fb6cafeb7a021dd5d775993 (diff)
New Style Generator (#8)
Diffstat (limited to 'style-generator/src/Decoder/Generic.elm')
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+module Decoder.Generic exposing (combine, pair, resultToDecoder, subdecode, tail, withDefault)
+
+import Json.Decode as D exposing (Decoder)
+
+
+withDefault : a -> Decoder a -> Decoder a
+withDefault fallback decoder =
+ D.oneOf
+ [ decoder
+ , D.succeed fallback
+ ]
+
+
+combine : List (Decoder a) -> Decoder (List a)
+combine =
+ List.foldr (D.map2 (::)) (D.succeed [])
+
+
+subdecode : Decoder a -> D.Value -> Decoder a
+subdecode d v =
+ D.decodeValue d v |> resultToDecoder
+
+
+tail : Decoder a -> Decoder (List a)
+tail itemDecoder =
+ D.list D.value
+ |> D.andThen
+ (\l ->
+ case l of
+ [] ->
+ D.fail "Can't get tail of empty"
+
+ head :: t ->
+ List.map (subdecode itemDecoder) t |> combine
+ )
+
+
+pair : Decoder a -> Decoder b -> Decoder ( a, b )
+pair aDecoder bDecoder =
+ D.map2 Tuple.pair
+ (D.index 0 aDecoder)
+ (D.index 1 bDecoder)
+
+
+resultToDecoder : Result D.Error a -> Decoder a
+resultToDecoder res =
+ case res of
+ Ok a ->
+ D.succeed a
+
+ Err e ->
+ D.fail (D.errorToString e)