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brandonchinn178brandonchinn178
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Use same Decoder type across Monad/Arrow
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Lines changed: 113 additions & 754 deletions

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‎kdl-hs.cabal‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -24,11 +24,12 @@ library
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hs-source-dirs: src
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exposed-modules:
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Data.KDL
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Data.KDL.Arrow
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Data.KDL.Decoder
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Data.KDL.Decoder.Arrow
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Data.KDL.Decoder.Arrow.Internal
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Data.KDL.Decoder.Internal.DecodeM
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Data.KDL.Decoder.Internal.Error
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Data.KDL.Decoder.Internal.Monad
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Data.KDL.Decoder.Monad
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Data.KDL.Decoder.Schema
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Data.KDL.Parser

‎src/Data/KDL.hs‎

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@@ -3,6 +3,10 @@ This module is intended to be imported qualified as:
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> import Data.KDL qualified as KDL
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This provides a Monad interface for decoding KDL files, which is sufficient for
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most cases. You may wish to use "Data.KDL.Arrow" if you would like to
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statically analyze a decoder's schema, e.g. to generate documentation.
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= Quickstart
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Given a file @config.kdl@:
@@ -47,14 +51,14 @@ data Dep = Dep
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deriving (Show)
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instance KDL.DecodeNode Config where
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nodeDecoder = KDL.noSchema $ do
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nodeDecoder = do
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name <- KDL.argAt "name"
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version <- KDL.argAt "version"
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dependencies <- KDL.nodeWith "dependencies" . KDL.children $ KDL.remainingNodes
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pure Config{..}
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instance KDL.DecodeNode Dep where
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nodeDecoder = KDL.noSchema $ do
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nodeDecoder = do
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version <- KDL.arg
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optional <- KDL.option False $ KDL.prop "optional"
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pure Dep{..}

‎src/Data/KDL/Arrow.hs‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,78 @@
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{-|
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This module defines the Arrow interface for decoding a KDL document. Intended to
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be imported qualified as:
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> import Data.KDL.Arrow qualified as KDL
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For most use-cases, the Monad interface exported by "Data.KDL" is sufficient. You
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may wish to use the Arrow interface if you would like to statically analyze a
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decoder's schema, e.g. to generate documentation.
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= Quickstart
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Given a file @config.kdl@:
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@
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package {
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name my-pkg
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version "1.2.3"
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dependencies {
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aeson ">= 2.2.3.0" optional=#true
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text ">= 2"
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}
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}
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@
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Parse it with:
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@
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{\-# LANGUAGE Arrows #-\}
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import Data.KDL.Decoder.Arrow qualified as KDL
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main :: IO ()
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main = do
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config <- KDL.decodeFileWith decoder "config.kdl"
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print config
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decoder :: KDL.Decoder Config
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decoder = KDL.document $ proc () -> do
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KDL.node "package" -< ()
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data Config = Config
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{ name :: Text
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, version :: Text
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, dependencies :: Map Text Dep
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}
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deriving (Show)
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data Dep = Dep
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{ version :: Text
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, optional :: Bool
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}
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deriving (Show)
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instance KDL.DecodeNode Config where
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nodeDecoder = proc () -> do
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name <- KDL.argAt "name" -< ()
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version <- KDL.argAt "version" -< ()
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dependencies <- KDL.nodeWith "dependencies" . KDL.children $ KDL.remainingNodes -< ()
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returnA -< Config{..}
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instance KDL.DecodeNode Dep where
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nodeDecoder = proc () -> do
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version <- KDL.arg -< ()
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optional <- KDL.option False $ KDL.prop "optional" -< ()
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returnA -< Dep{..}
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@
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-}
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module Data.KDL.Arrow (
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module X,
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) where
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import Data.KDL.Decoder.Arrow as X
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import Data.KDL.Decoder.Schema as X
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import Data.KDL.Parser as X
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import Data.KDL.Render as X
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import Data.KDL.Types as X

‎src/Data/KDL/Decoder/Arrow.hs‎

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Original file line numberDiff line numberDiff line change
@@ -5,75 +5,6 @@
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{-# LANGUAGE OverloadedStrings #-}
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{-# LANGUAGE TypeFamilies #-}
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{-|
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This module defines the Arrow interface for decoding a KDL document. Intended to
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be imported qualified as:
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> import Data.KDL.Decoder.Arrow qualified as KDL
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For most use-cases, the Monad interface exported by "Data.KDL" is sufficient. You
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may wish to use the Arrow interface if you would like to statically analyze a
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decoder's schema, e.g. to generate documentation.
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18-
= Quickstart
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Given a file @config.kdl@:
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@
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package {
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name my-pkg
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version "1.2.3"
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dependencies {
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aeson ">= 2.2.3.0" optional=#true
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text ">= 2"
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}
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}
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@
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Parse it with:
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@
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{\-# LANGUAGE Arrows #-\}
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import Data.KDL.Decoder.Arrow qualified as KDL
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main :: IO ()
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main = do
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config <- KDL.decodeFileWith decoder "config.kdl"
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print config
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decoder :: KDL.Decoder Config
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decoder = KDL.document $ proc () -> do
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KDL.node "package" -< ()
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data Config = Config
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{ name :: Text
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, version :: Text
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, dependencies :: Map Text Dep
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}
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deriving (Show)
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data Dep = Dep
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{ version :: Text
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, optional :: Bool
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}
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deriving (Show)
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instance KDL.DecodeNode Config where
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nodeDecoder = proc () -> do
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name <- KDL.argAt "name" -< ()
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version <- KDL.argAt "version" -< ()
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dependencies <- KDL.nodeWith "dependencies" . KDL.children $ KDL.remainingNodes -< ()
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returnA -< Config{..}
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instance KDL.DecodeNode Dep where
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nodeDecoder = proc () -> do
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version <- KDL.arg -< ()
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optional <- KDL.option False $ KDL.prop "optional" -< ()
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returnA -< Dep{..}
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@
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-}
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module Data.KDL.Decoder.Arrow (
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decodeWith,
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decodeFileWith,
@@ -160,8 +91,8 @@ import Control.Monad.Trans.State.Strict (StateT)
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import Control.Monad.Trans.State.Strict qualified as StateT
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import Data.Bits (finiteBitSize)
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import Data.Int (Int64)
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import Data.KDL.Decoder.Arrow.Internal
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import Data.KDL.Decoder.Internal.DecodeM
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import Data.KDL.Decoder.Internal.Monad
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import Data.KDL.Decoder.Schema (
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Schema (..),
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SchemaItem (..),

src/Data/KDL/Decoder/Arrow/Internal.hs renamed to src/Data/KDL/Decoder/Internal/Monad.hs

Lines changed: 11 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,7 @@
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{-# LANGUAGE OverloadedRecordDot #-}
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{-# LANGUAGE TypeFamilies #-}
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4-
module Data.KDL.Decoder.Arrow.Internal (
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module Data.KDL.Decoder.Internal.Monad (
55
-- * Decoder
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Decoder (..),
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liftDecodeM,
@@ -94,7 +94,8 @@ runDecodeStateM o hist m =
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-- | @Decoder o a b@ represents an arrow with input @a@ and output @b@, within
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-- the context of decoding a KDL object of type @o@. It also knows the expected
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-- schema of @o@.
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-- schema of @o@. Most of the time, @a@ is @()@; it would only be different if
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-- you're using Arrows notation.
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--
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-- We're using arrows here so that we can:
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--
@@ -140,6 +141,14 @@ instance Alternative (Decoder o a) where
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in go
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many (Decoder sch run) = some (Decoder sch run) <|> pure []
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-- | Eliminates all schema information; avoid whenever possible.
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instance Monad (Decoder o a) where
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Decoder _ run1 >>= k =
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Decoder SchemaUnknown $ \a -> do
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x <- run1 a
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let Decoder _ run2 = k x
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run2 a
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liftDecodeM :: (a -> DecodeM b) -> Decoder o a b
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liftDecodeM f = Decoder (SchemaAnd []) (Trans.lift . f)
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