graphql/Data/GraphQL/AST.hs
2016-11-27 12:56:44 -03:00

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