175 lines
6.0 KiB
Haskell
175 lines
6.0 KiB
Haskell
-- | This module defines an abstract syntax tree for the @GraphQL@ language based on
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-- <https://facebook.github.io/graphql/ Facebook's GraphQL Specification>.
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module Data.GraphQL.AST where
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import Data.Int (Int32)
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import Data.String (IsString(fromString))
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import Data.Text (Text, pack)
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-- * Name
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type Name = Text
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-- * Document
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newtype Document = Document [Definition] deriving (Eq,Show)
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data Definition = DefinitionOperation OperationDefinition
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| DefinitionFragment FragmentDefinition
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| DefinitionType TypeDefinition
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deriving (Eq,Show)
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data OperationDefinition = Query Node
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| Mutation Node
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deriving (Eq,Show)
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data Node = Node Name [VariableDefinition] [Directive] SelectionSet
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deriving (Eq,Show)
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data VariableDefinition = VariableDefinition Variable Type (Maybe DefaultValue)
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deriving (Eq,Show)
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newtype Variable = Variable Name deriving (Eq,Show)
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instance IsString Variable where
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fromString = Variable . pack
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type SelectionSet = [Selection]
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data Selection = SelectionField Field
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| SelectionFragmentSpread FragmentSpread
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| SelectionInlineFragment InlineFragment
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deriving (Eq,Show)
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-- | A 'SelectionSet' is primarily composed of 'Field's. A 'Field' describes one
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-- discrete piece of information available to request within a 'SelectionSet'.
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--
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-- Some 'Field's describe complex data or relationships to other data. In
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-- order to further explore this data, a 'Field' may itself contain a
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-- 'SelectionSet', allowing for deeply nested requests. All @GraphQL@ operations
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-- must specify their 'Selection's down to 'Field's which return scalar values to
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-- ensure an unambiguously shaped response.
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--
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-- <https://facebook.github.io/graphql/#sec-Language.Query-Document.Fields Field Specification>
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data Field = Field Alias Name [Argument] [Directive] SelectionSet
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deriving (Eq,Show)
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type Alias = Name
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-- | 'Field's are conceptually functions which return values, and occasionally accept
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-- 'Argument's which alter their behavior. These 'Argument's often map directly to
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-- function arguments within a @GraphQL@ server’s implementation.
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--
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-- <https://facebook.github.io/graphql/#sec-Language.Query-Document.Arguments Argument Specification>
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data Argument = Argument Name Value deriving (Eq,Show)
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-- * Fragments
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data FragmentSpread = FragmentSpread Name [Directive]
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deriving (Eq,Show)
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data InlineFragment =
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InlineFragment TypeCondition [Directive] SelectionSet
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deriving (Eq,Show)
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data FragmentDefinition =
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FragmentDefinition Name TypeCondition [Directive] SelectionSet
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deriving (Eq,Show)
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type TypeCondition = NamedType
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-- * Values
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-- | 'Field' and 'Directive' 'Arguments' accept input values of various literal
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-- primitives; input values can be scalars, enumeration values, lists, or input
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-- objects.
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--
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-- If not defined as constant (for example, in 'DefaultValue'), input values
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-- can be specified as a 'Variable'. List and inputs objects may also contain
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-- 'Variable's (unless defined to be constant).
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--
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-- <https://facebook.github.io/graphql/#sec-Input-Values Input Value Specification>
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data Value = ValueVariable Variable
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| ValueInt Int32
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-- GraphQL Float is double precison
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| ValueFloat Double
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| ValueBoolean Bool
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| ValueString Text
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| ValueEnum Name
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| ValueList ListValue
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| ValueObject ObjectValue
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deriving (Eq,Show)
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newtype ListValue = ListValue [Value] deriving (Eq,Show)
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newtype ObjectValue = ObjectValue [ObjectField] deriving (Eq,Show)
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data ObjectField = ObjectField Name Value deriving (Eq,Show)
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type DefaultValue = Value
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-- * Directives
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data Directive = Directive Name [Argument] deriving (Eq,Show)
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-- * Type Reference
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data Type = TypeNamed NamedType
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| TypeList ListType
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| TypeNonNull NonNullType
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deriving (Eq,Show)
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newtype NamedType = NamedType Name deriving (Eq,Show)
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newtype ListType = ListType Type deriving (Eq,Show)
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data NonNullType = NonNullTypeNamed NamedType
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| NonNullTypeList ListType
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deriving (Eq,Show)
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-- * Type definition
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data TypeDefinition = TypeDefinitionObject ObjectTypeDefinition
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| TypeDefinitionInterface InterfaceTypeDefinition
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| TypeDefinitionUnion UnionTypeDefinition
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| TypeDefinitionScalar ScalarTypeDefinition
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| TypeDefinitionEnum EnumTypeDefinition
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| TypeDefinitionInputObject InputObjectTypeDefinition
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| TypeDefinitionTypeExtension TypeExtensionDefinition
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deriving (Eq,Show)
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data ObjectTypeDefinition = ObjectTypeDefinition Name Interfaces [FieldDefinition]
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deriving (Eq,Show)
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type Interfaces = [NamedType]
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data FieldDefinition = FieldDefinition Name ArgumentsDefinition Type
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deriving (Eq,Show)
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type ArgumentsDefinition = [InputValueDefinition]
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data InputValueDefinition = InputValueDefinition Name Type (Maybe DefaultValue)
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deriving (Eq,Show)
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data InterfaceTypeDefinition = InterfaceTypeDefinition Name [FieldDefinition]
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deriving (Eq,Show)
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data UnionTypeDefinition = UnionTypeDefinition Name [NamedType]
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deriving (Eq,Show)
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data ScalarTypeDefinition = ScalarTypeDefinition Name
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deriving (Eq,Show)
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data EnumTypeDefinition = EnumTypeDefinition Name [EnumValueDefinition]
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deriving (Eq,Show)
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newtype EnumValueDefinition = EnumValueDefinition Name
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deriving (Eq,Show)
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data InputObjectTypeDefinition = InputObjectTypeDefinition Name [InputValueDefinition]
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deriving (Eq,Show)
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newtype TypeExtensionDefinition = TypeExtensionDefinition ObjectTypeDefinition
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deriving (Eq,Show)
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