Move related modules to Language.GraphQL.AST

Fixes #18.

- `Language.GraphQL.Encoder` moved to `Language.GraphQL.AST.Encoder`.
- `Language.GraphQL.Parser` moved to `Language.GraphQL.AST.Parser`.
- `Language.GraphQL.Lexer` moved to `Language.GraphQL.AST.Lexer`.
- All `Language.GraphQL.AST.Value` data constructor prefixes were removed. The
  module should be imported qualified.
- All `Language.GraphQL.AST.Core.Value` data constructor prefixes were removed.
  The module should be imported qualified.
- `Language.GraphQL.AST.Transform` is now isn't exposed publically anymore.

src/Language/GraphQL/AST.hs

@@ -29,16 +29,15 @@ module Language.GraphQL.AST
 import Data.Int (Int32)
 import Data.List.NonEmpty (NonEmpty)
 import Data.Text (Text)
-import Language.GraphQL.AST.Core ( Alias
-                                 , Name
-                                 , TypeCondition
-                                 )
 
 -- * Document
 
 -- | GraphQL document.
 type Document = NonEmpty Definition
 
+-- | Name
+type Name = Text
+
 -- | Directive.
 data Directive = Directive Name [Argument] deriving (Eq, Show)
 
@@ -82,12 +81,56 @@ data Selection
 
 -- * Field
 
--- | GraphQL field.
+-- | Single GraphQL field.
+--
+-- The only required property of a field is its name. Optionally it can also
+-- have an alias, arguments or a list of subfields.
+--
+-- Given the following query:
+--
+-- @
+-- {
+--   zuck: user(id: 4) {
+--     id
+--     name
+--   }
+-- }
+-- @
+--
+-- * "user", "id" and "name" are field names.
+-- * "user" has two subfields, "id" and "name".
+-- * "zuck" is an alias for "user". "id" and "name" have no aliases.
+-- * "id: 4" is an argument for "name". "id" and "name don't have any
+-- arguments.
 data Field
     = Field (Maybe Alias) Name [Argument] [Directive] SelectionSetOpt
     deriving (Eq, Show)
 
--- | Argument.
+-- | Alternative field name.
+--
+-- @
+-- {
+--   smallPic: profilePic(size: 64)
+--   bigPic: profilePic(size: 1024)
+-- }
+-- @
+--
+-- Here "smallPic" and "bigPic" are aliases for the same field, "profilePic",
+-- used to distinquish between profile pictures with different arguments
+-- (sizes).
+type Alias = Name
+
+-- | Single argument.
+--
+-- @
+-- {
+--   user(id: 4) {
+--     name
+--   }
+-- }
+-- @
+--
+--  Here "id" is an argument for the field "user" and its value is 4.
 data Argument = Argument Name Value deriving (Eq,Show)
 
 -- * Fragments
@@ -107,15 +150,15 @@ data FragmentDefinition
 -- * Inputs
 
 -- | Input value.
-data Value = ValueVariable Name
-           | ValueInt Int32
-           | ValueFloat Double
-           | ValueString Text
-           | ValueBoolean Bool
-           | ValueNull
-           | ValueEnum Name
-           | ValueList [Value]
-           | ValueObject [ObjectField]
+data Value = Variable Name
+           | Int Int32
+           | Float Double
+           | String Text
+           | Boolean Bool
+           | Null
+           | Enum Name
+           | List [Value]
+           | Object [ObjectField]
            deriving (Eq, Show)
 
 -- | Key-value pair.
@@ -127,13 +170,15 @@ data ObjectField = ObjectField Name Value deriving (Eq, Show)
 data VariableDefinition = VariableDefinition Name Type (Maybe Value)
                           deriving (Eq, Show)
 
+-- | Type condition.
+type TypeCondition = Name
+
 -- | Type representation.
 data Type = TypeNamed   Name
           | TypeList    Type
           | TypeNonNull NonNullType
             deriving (Eq, Show)
 
-
 -- | Helper type to represent Non-Null types and lists of such types.
 data NonNullType = NonNullTypeNamed Name
                  | NonNullTypeList  Type