forked from OSS/graphql
693b7d18dc
In the Transform module the Full AST will converted to Core AST. This commit also includes a partial implementation of Fragment replacement.
87 lines
3.0 KiB
Haskell
87 lines
3.0 KiB
Haskell
module Data.GraphQL.AST.Transform where
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import Control.Applicative (empty)
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import Data.Bifunctor (first)
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import Data.Either (partitionEithers)
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import qualified Data.List.NonEmpty as NonEmpty
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-- import Data.List.NonEmpty (NonEmpty((:|)))
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import Data.Monoid (Alt(Alt,getAlt))
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import Data.Foldable (foldMap)
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import Data.Text (Text)
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import qualified Data.GraphQL.AST as Full
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import qualified Data.GraphQL.AST.Core as Core
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import qualified Data.GraphQL.Schema as Schema
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type Name = Text
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-- | Replaces a fragment name by a list of 'Field'. If the name doesn't match an
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-- empty list is returned.
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type Fragmenter = Name -> [Core.Field]
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document :: Schema.Subs -> Full.Document -> Core.Document
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document subs defs = operations subs fr ops
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where
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(fr, ops) = first foldFrags . partitionEithers . NonEmpty.toList $ defrag <$> defs
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foldFrags :: [Fragmenter] -> Fragmenter
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foldFrags fs n = getAlt $ foldMap (Alt . ($ n)) fs
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-- * Fragment replacement
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-- | Extract Fragments into a single Fragmenter function and a Operation
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-- Definition.
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defrag :: Full.Definition -> Either Fragmenter Full.OperationDefinition
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defrag (Full.DefinitionOperation op) = Right op
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defrag (Full.DefinitionFragment fragDef) = Left $ fragmentDefinition fragDef
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fragmentDefinition :: Full.FragmentDefinition -> Fragmenter
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fragmentDefinition (Full.FragmentDefinition name _tc _dirs sels) name' =
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if name == name' then NonEmpty.toList (selection <$> sels) else empty
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selection :: Full.Selection -> Core.Field
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selection (Full.SelectionField _fld) = field _fld
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selection (Full.SelectionFragmentSpread _) = error "Nested fragments not supported yet"
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selection (Full.SelectionInlineFragment _) =
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error "Inline fragments within fragments not supported yet"
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field :: Full.Field -> Core.Field
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field (Full.Field a n args _ sels) =
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Core.Field a n (argument <$> args) (selection <$> sels)
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argument :: Full.Argument -> Core.Argument
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argument (Full.Argument n v) = Core.Argument n (value v)
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value :: Full.Value -> Core.Value
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value (Full.ValueVariable _) = error "Variables within fragments not supported yet"
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value (Full.ValueInt i) = Core.ValueInt i
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value (Full.ValueFloat f) = Core.ValueFloat f
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value (Full.ValueString x) = Core.ValueString x
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value (Full.ValueBoolean b) = Core.ValueBoolean b
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value Full.ValueNull = Core.ValueNull
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value (Full.ValueEnum e) = Core.ValueEnum e
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value (Full.ValueList l) = Core.ValueList (value <$> l)
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value (Full.ValueObject o) = Core.ValueObject (objectField <$> o)
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objectField :: Full.ObjectField -> Core.ObjectField
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objectField (Full.ObjectField n v) = Core.ObjectField n (value v)
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-- * Operation
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operations
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:: Schema.Subs
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-> Fragmenter
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-> [Full.OperationDefinition]
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-> Core.Document
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-- XXX: Replace `fromList` by proper error: at least a Query or Mutation
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-- operation must be present
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operations subs fr = NonEmpty.fromList . fmap (operation subs fr)
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operation
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:: Schema.Subs
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-> Fragmenter
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-> Full.OperationDefinition
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-> Core.Operation
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operation _subs _fr _op = undefined
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