railt/json

/**
 * --------------------------------------------------------------------------
 *  JSON5 Grammar
 * --------------------------------------------------------------------------
 *
 * The JSON5 Data Interchange Format (JSON5) is a superset of JSON that
 * aims to alleviate some of the limitations of JSON by expanding its
 * syntax to include some productions from ECMAScript 5.1.
 *
 * Similar to JSON, JSON5 can represent four primitive types
 * (strings, numbers, Booleans, and null) and two structured types
 * (objects and arrays).
 *
 * A string is a sequence of zero or more Unicode characters. Note that
 * this citation references the latest version of Unicode rather than a
 * specific release. It is not expected that future changes in the Unicode
 * specification will impact the syntax of JSON5.
 *
 * An object is an unordered collection of zero or more name/value pairs,
 * where a name is a string or identifier and a value is a string, number,
 * Boolean, null, object, or array.
 *
 * An array is an ordered sequence of zero or more values.
 *
 * @see https://spec.json5.org/
 * @see http://www.unicode.org/versions/Unicode11.0.0/
 * @see https://tools.ietf.org/html/rfc7159
 * @see https://www.ecma-international.org/ecma-262/5.1/
 */

%include lexemes.pp2


#Json -> Railt\Json\Json5\Ast\Json5Node
  : Value()
  ;

Value
  : Object()
  | Array()
  | String()
  | Boolean()
  | Null()
  | Inf()
  | NaN()
  | Hex()
  | Float()
  | Int()
  ;

#Object -> Railt\Json\Json5\Ast\ObjectNode
  : ::T_BRACE_OPEN::
      ObjectBody()? ::T_COMMA::?
    ::T_BRACE_CLOSE::
  ;

ObjectBody
  : (ObjectPair() ::T_COMMA::)* ObjectPair()
  ;

#ObjectPair
  : ObjectKey() ::T_COLON:: ObjectValue()
  ;

ObjectKey
  : String()
  | Identifier()
  ;

ObjectValue
  : Value()
  ;

#Array -> Railt\Json\Json5\Ast\ArrayNode
  : ::T_BRACKET_OPEN::
      ArrayBody()? ::T_COMMA::?
    ::T_BRACKET_CLOSE::
  ;

ArrayBody
  : (Value() ::T_COMMA::)* Value()
  ;

#String -> Railt\Json\Json5\Ast\StringNode
  : <T_DOUBLE_QUOTED_STRING>
  | <T_SINGLE_QUOTED_STRING>
  ;

#Boolean -> Railt\Json\Json5\Ast\BoolNode
  : <T_BOOL_TRUE>
  | <T_BOOL_FALSE>
  ;

#Null -> Railt\Json\Json5\Ast\NullNode
  : ::T_NULL::
  ;

#Identifier -> Railt\Json\Json5\Ast\IdentifierNode
  : <T_IDENTIFIER>
  ;

//
// Numbers
//

#Sign
  : <T_PLUS>
  | <T_MINUS>
  ;

#ExponentPart
  : <T_EXPONENT_PART>
  ;

#Inf -> Railt\Json\Json5\Ast\InfNode
  : Sign()? <T_INF>
  ;

#NaN -> Railt\Json\Json5\Ast\NaNNode
  : Sign()? <T_NAN>
  ;

#Float -> Railt\Json\Json5\Ast\FloatNode
  : Sign()? (<T_FLOAT_LD_NUMBER> | <T_FLOAT_TG_NUMBER>) ExponentPart()?
  ;

#Int -> Railt\Json\Json5\Ast\IntNode
  : Sign()? <T_INT_NUMBER> ExponentPart()?
  ;

#Hex -> Railt\Json\Json5\Ast\HexNode
  : Sign()? <T_HEX_NUMBER>
  ;