103 lines
2.3 KiB
Haskell
103 lines
2.3 KiB
Haskell
-- | This is the AST meant to be executed.
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module Language.GraphQL.AST.Core
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( Alias
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, Argument(..)
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, Document
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, Field(..)
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, Name
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, ObjectField(..)
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, Operation(..)
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, Value(..)
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) where
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import Data.Int (Int32)
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import Data.List.NonEmpty (NonEmpty)
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import Data.String
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import Data.Text (Text)
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-- | Name
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type Name = Text
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-- | GraphQL document is a non-empty list of operations.
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type Document = NonEmpty Operation
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-- | GraphQL has 3 operation types: queries, mutations and subscribtions.
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--
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-- Currently only queries and mutations are supported.
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data Operation
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= Query (Maybe Text) (NonEmpty Field)
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| Mutation (Maybe Text) (NonEmpty Field)
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deriving (Eq, Show)
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-- | A single GraphQL field.
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--
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-- Only required property of a field, is its name. Optionally it can also have
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-- an alias, arguments or a list of subfields.
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--
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-- Given the following query:
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--
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-- @
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-- {
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-- zuck: user(id: 4) {
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-- id
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-- name
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-- }
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-- }
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-- @
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--
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-- * "user", "id" and "name" are field names.
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-- * "user" has two subfields, "id" and "name".
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-- * "zuck" is an alias for "user". "id" and "name" have no aliases.
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-- * "id: 4" is an argument for "name". "id" and "name don't have any
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-- arguments.
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data Field = Field (Maybe Alias) Name [Argument] [Field] deriving (Eq, Show)
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-- | Alternative field name.
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--
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-- @
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-- {
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-- smallPic: profilePic(size: 64)
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-- bigPic: profilePic(size: 1024)
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-- }
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-- @
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--
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-- Here "smallPic" and "bigPic" are aliases for the same field, "profilePic",
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-- used to distinquish between profile pictures with different arguments
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-- (sizes).
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type Alias = Name
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-- | Single argument.
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--
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-- @
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-- {
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-- user(id: 4) {
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-- name
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-- }
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-- }
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-- @
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--
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-- Here "id" is an argument for the field "user" and its value is 4.
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data Argument = Argument Name Value deriving (Eq, Show)
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-- | Represents accordingly typed GraphQL values.
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data Value
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= ValueInt Int32
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-- GraphQL Float is double precision
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| ValueFloat Double
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| ValueString Text
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| ValueBoolean Bool
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| ValueNull
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| ValueEnum Name
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| ValueList [Value]
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| ValueObject [ObjectField]
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deriving (Eq, Show)
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instance IsString Value where
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fromString = ValueString . fromString
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-- | Key-value pair.
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--
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-- A list of 'ObjectField's represents a GraphQL object type.
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data ObjectField = ObjectField Name Value deriving (Eq, Show)
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