// https://spec.graphql.org/June2018/

// TODO:
// - try removing precedence operators
// - match tokens more
// - add lexical tokens thing

@top document { Document }
@precedence {
  alias,
  directive,
  defn
}

@skip { whitespace | Comment | ","}
@detectDelim

/* macros */
kw<word> { @specialize[@name={word}]<name, word> }

/* https://spec.graphql.org/June2018/#sec-Appendix-Grammar-Summary.Lexical-Tokens */
@tokens {
  // Punctuator { $[!\$():=@\[\]{|}] | "..." }
  
  name { $[_A-Za-z] $[_0-9A-Za-z]* }

  IntValue { IntegerPart }

  IntegerPart { NegativeSign? "0" | NegativeSign? NonZeroDigit Digit* }

  NegativeSign { "-" }

  Digit { $[0-9] }

  NonZeroDigit { $[1-9] }

  FloatValue {
    IntegerPart FractionalPart |
    IntegerPart ExponentPart |
    IntegerPart FractionalPart ExponentPart
  }

  FractionalPart { "." Digit* }
  
  ExponentPart { ExponentIndicator Sign? Digit+ }

  ExponentIndicator { "e" | "E" }

  Sign { "+" | "-" }

  StringValue { '"' (![\\\n"] | "\\" _)* '"'? }

  boolean { "true" | "false" }
  null { "null" }
  whitespace { $[ \t] }

  Comment { "#" ![\n\r]* }

  "{" "}"

  @precedence {
    boolean,
    null,
    FloatValue,
    IntValue,
    name
  }
}

/* https://spec.graphql.org/June2018/#sec-Appendix-Grammar-Summary.Document */

// https://spec.graphql.org/June2018/#Document
Document { Definition+ }

// https://spec.graphql.org/June2018/#Definition
Definition {
  ExecutableDefinition |
  TypeSystemDefinition |
  TypeSystemExtension
}

// https://spec.graphql.org/June2018/#ExecutableDefinition
ExecutableDefinition {
  OperationDefinition |
  FragmentDefinition
}

// https://spec.graphql.org/June2018/#OperationDefinition
OperationDefinition {
  OperationType name? VariableDefinitions? Directives? SelectionSet |
  SelectionSet
}

// https://spec.graphql.org/June2018/#OperationType
OperationType {
  kw<"query"> |
  kw<"mutation"> |
  kw<"subscription">
}

// https://spec.graphql.org/June2018/#SelectionSet
SelectionSet {
  "{" Selection+ "}"
}

// https://spec.graphql.org/June2018/#Selection
Selection {
  Field |
  FragmentSpread |
  InlineFragment
}

// https://spec.graphql.org/June2018/#Field
Field {
  Alias? name Arguments? Directives? SelectionSet?
}

// https://spec.graphql.org/June2018/#Alias
Alias {
  name ":" !alias
}

// https://spec.graphql.org/June2018/#Arguments
Arguments {
  "(" Argument+ ")"
}

Arguments_Const {
  "(" Argument_Const+ ")"
}

// https://spec.graphql.org/June2018/#Argument
Argument {
  name ":" Value
}

Argument_Const {
  name ":" Value_Const
}

// https://spec.graphql.org/June2018/#FragmentSpread
FragmentSpread {
  "..." FragmentName Directives?
}

// https://spec.graphql.org/June2018/#InlineFragment
InlineFragment {
  "..." TypeCondition? Directives? SelectionSet
}

// https://spec.graphql.org/June2018/#FragmentDefinition
FragmentDefinition {
  kw<"fragment"> FragmentName TypeCondition Directives? SelectionSet
}

// https://spec.graphql.org/June2018/#FragmentName
FragmentName {
  name
}

// https://spec.graphql.org/June2018/#TypeCondition
TypeCondition {
  kw<"on"> NamedType
}

// https://spec.graphql.org/June2018/#Value
Value {
  Variable |
  IntValue |
  FloatValue |
  StringValue |
  BooleanValue |
  NullValue |
  EnumValue |
  ListValue |
  ObjectValue
}

Value_Const {
  IntValue |
  FloatValue |
  StringValue |
  BooleanValue |
  NullValue |
  EnumValue |
  ListValue_Const |
  ObjectValue_Const
}

// https://spec.graphql.org/June2018/#BooleanValue
BooleanValue {
  boolean
}

// https://spec.graphql.org/June2018/#NullValue
NullValue {
  null
}

// https://spec.graphql.org/June2018/#EnumValue
EnumValue {
  name
}

// https://spec.graphql.org/June2018/#ListValue
ListValue {
  "[" Value* "]"
}

ListValue_Const {
  "[" Value_Const* "]"
}

// https://spec.graphql.org/June2018/#ObjectValue
ObjectValue {
  "{" ObjectField* "}"
}

ObjectValue_Const {
  "{" ObjectField_Const* "}"
}

// https://spec.graphql.org/June2018/#ObjectField
ObjectField {
  name ":" Value
}

ObjectField_Const {
  name ":" Value_Const
}

// https://spec.graphql.org/June2018/#VariableDefinitions
VariableDefinitions {
  "(" VariableDefinition+ ")"
}

// https://spec.graphql.org/June2018/#VariableDefinition
VariableDefinition {
  Variable ":" Type DefaultValue?
}

// https://spec.graphql.org/June2018/#Variable
Variable {
  "$" name
}

// https://spec.graphql.org/June2018/#DefaultValue
DefaultValue {
  "=" Value_Const
}

// https://spec.graphql.org/June2018/#Type
Type {
  NamedType |
  ListType |
  NonNullType
}

// https://spec.graphql.org/June2018/#NamedType
NamedType {
  name
}

// https://spec.graphql.org/June2018/#ListType
ListType {
  "[" Type "]"
}

// https://spec.graphql.org/June2018/#NonNullType
NonNullType {
  NamedType "!" |
  ListType "!"
}

// https://spec.graphql.org/June2018/#Directives
Directives {
  Directive+
}

Directives_Const {
  Directive_Const+
}

// https://spec.graphql.org/June2018/#Directive
Directive {
  "@" name Arguments?
}

Directive_Const {
  "@" name Arguments_Const?
}

// https://spec.graphql.org/June2018/#TypeSystemDefinition
TypeSystemDefinition {
  SchemaDefinition |
  TypeDefinition |
  DirectiveDefinition
}

// https://spec.graphql.org/June2018/#TypeSystemExtension
TypeSystemExtension {
  SchemaExtension |
  TypeExtension
}

// https://spec.graphql.org/June2018/#SchemaDefinition
SchemaDefinition {
  kw<"schema"> Directives_Const? "{" OperationTypeDefinition+ "}"
}

// https://spec.graphql.org/June2018/#SchemaExtension
SchemaExtension {
  kw<"extend"> kw<"schema"> Directives_Const? !alias "{" OperationTypeDefinition+ "}" |
  kw<"extend"> kw<"schema"> Directives_Const
}

// https://spec.graphql.org/June2018/#OperationTypeDefinition
OperationTypeDefinition {
  OperationType ":" NamedType
}

// https://spec.graphql.org/June2018/#Description
Description {
  StringValue
}

// https://spec.graphql.org/June2018/#TypeDefinition
TypeDefinition {
  ScalarTypeDefinition |
  ObjectTypeDefinition |
  InterfaceTypeDefinition |
  UnionTypeDefinition |
  EnumTypeDefinition |
  InputObjectTypeDefinition
}

// https://spec.graphql.org/June2018/#TypeExtension
TypeExtension {
  ScalarTypeExtension |
  ObjectTypeExtension |
  InterfaceTypeExtension |
  UnionTypeExtension |
  EnumTypeExtension |
  InputObjectTypeExtension
}

// https://spec.graphql.org/June2018/#ScalarTypeDefinition
ScalarTypeDefinition {
  Description? kw<"scalar"> name Directives_Const?
}

// https://spec.graphql.org/June2018/#ScalarTypeExtension
ScalarTypeExtension {
  kw<"extend"> kw<"scalar"> name Directives_Const
}

// https://spec.graphql.org/June2018/#ObjectTypeDefinition
ObjectTypeDefinition {
  Description? kw<"type"> name ImplementsInterfaces? Directives_Const? FieldsDefinition?
}

// https://spec.graphql.org/June2018/#ObjectTypeExtension
ObjectTypeExtension {
  kw<"extend"> kw<"type"> name ImplementsInterfaces? Directives_Const? FieldsDefinition |
  kw<"extend"> kw<"type"> name ImplementsInterfaces? Directives_Const |
  kw<"extend"> kw<"type"> name ImplementsInterfaces
}

// https://spec.graphql.org/June2018/#ImplementsInterfaces
ImplementsInterfaces {
  kw<"implements"> "&"? NamedType |
  ImplementsInterfaces "&" NamedType
}

// https://spec.graphql.org/June2018/#FieldsDefinition
FieldsDefinition {
  !defn "{" FieldDefinition+ "}"
} 

// https://spec.graphql.org/June2018/#FieldDefinition
FieldDefinition {
  Description? name ArgumentsDefinition? ":" Type Directives_Const? 
}

// https://spec.graphql.org/June2018/#ArgumentsDefinition
ArgumentsDefinition {
  "(" InputValueDefinition+ ")"
}

// https://spec.graphql.org/June2018/#InputValueDefinition
InputValueDefinition {
  Description? name ":" Type DefaultValue? Directives_Const? 
}

// https://spec.graphql.org/June2018/#InterfaceTypeDefinition
InterfaceTypeDefinition {
  Description? kw<"interface"> name Directives_Const? FieldsDefinition? 
}

// https://spec.graphql.org/June2018/#InterfaceTypeExtension
InterfaceTypeExtension {
  kw<"extend"> kw<"interface"> name Directives_Const? FieldsDefinition |
  kw<"extend"> kw<"interface"> name Directives_Const
}

// https://spec.graphql.org/June2018/#UnionTypeDefinition
UnionTypeDefinition {
  Description? kw<"union"> name Directives_Const? UnionMemberTypes? 
}

// https://spec.graphql.org/June2018/#UnionMemberTypes
UnionMemberTypes {
  "=" "|"? NamedType |
  UnionMemberTypes "|" NamedType
}

// https://spec.graphql.org/June2018/#UnionTypeExtension
UnionTypeExtension {
  kw<"extend"> kw<"union"> name Directives_Const? UnionMemberTypes |
  kw<"extend"> kw<"union"> name Directives_Const
}

// https://spec.graphql.org/June2018/#EnumTypeDefinition
EnumTypeDefinition {
  Description? kw<"enum"> name Directives_Const? EnumValuesDefinition? 
}

// https://spec.graphql.org/June2018/#EnumValuesDefinition
EnumValuesDefinition {
  !defn
  "{" EnumValueDefinition+ "}"
}

// https://spec.graphql.org/June2018/#EnumValueDefinition
EnumValueDefinition {
  Description? EnumValue Directives_Const? 
}

// https://spec.graphql.org/June2018/#EnumTypeExtension
EnumTypeExtension {
  kw<"extend"> kw<"enum"> name Directives_Const? EnumValuesDefinition |
  kw<"extend"> kw<"enum"> name Directives_Const
}

// https://spec.graphql.org/June2018/#InputObjectTypeDefinition
InputObjectTypeDefinition {
  Description? kw<"input"> name Directives_Const? InputFieldsDefinition? 
}

// https://spec.graphql.org/June2018/#InputFieldsDefinition
InputFieldsDefinition {
  !defn
  "{" InputValueDefinition+ "}"
}

// https://spec.graphql.org/June2018/#InputObjectTypeExtension
InputObjectTypeExtension {
  kw<"extend"> kw<"input"> name Directives_Const? InputFieldsDefinition |
  kw<"extend"> kw<"input"> name Directives_Const
}

// https://spec.graphql.org/June2018/#DirectiveDefinition
DirectiveDefinition {
  Description? kw<"directive"> "@" name ArgumentsDefinition? kw<"on"> DirectiveLocations
}

// https://spec.graphql.org/June2018/#DirectiveLocations
DirectiveLocations {
  "|"? DirectiveLocation |
  DirectiveLocations "|" DirectiveLocation
}

// https://spec.graphql.org/June2018/#DirectiveLocation
DirectiveLocation {
  ExecutableDirectiveLocation |
  TypeSystemDirectiveLocation
}

// https://spec.graphql.org/June2018/#ExecutableDirectiveLocation
ExecutableDirectiveLocation {
  "QUERY" |
  "MUTATION" |
  "SUBSCRIPTION" |
  "FIELD" |
  "FRAGMENT_DEFINITION" |
  "FRAGMENT_SPREAD" |
  "INLINE_FRAGMENT"
}

// https://spec.graphql.org/June2018/#TypeSystemDirectiveLocation
TypeSystemDirectiveLocation {
  "SCHEMA" |
  "SCALAR" |
  "OBJECT" |
  "FIELD_DEFINITION" |
  "ARGUMENT_DEFINITION" |
  "INTERFACE" |
  "UNION" |
  "ENUM" |
  "ENUM_VALUE" |
  "INPUT_OBJECT" |
  "INPUT_FIELD_DEFINITION"
}