Class: TSJSON::Parser

Inherits:
Object
  • Object
show all
Defined in:
lib/language/parser/parser.rb

Instance Method Summary collapse

Constructor Details

#initialize(source) ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/language/parser/parser.rb', line 8

def initialize(source)
  source = Source.new(source) unless source.is_a?(Source)
  @lexer = Lexer.new(source)
end

Instance Method Details

#current_token ⇒ Object

Returns current token from lexer



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# File 'lib/language/parser/parser.rb', line 345

def current_token
  @lexer.token
end

#expect_optional_token(kind) ⇒ Object

If the next token is of the given kind, return that token after advancing the lexer. Otherwise, do not change the parser state and return undefined.



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# File 'lib/language/parser/parser.rb', line 428

def expect_optional_token(kind)
  token = current_token
  if token.kind === kind
    @lexer.advance
    return token
  end
  return nil
end

#expect_token(kind) ⇒ Object

If the next token is of the given kind, return that token after advancing the lexer. Otherwise, do not change the parser state and throw an error.



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# File 'lib/language/parser/parser.rb', line 410

def expect_token(kind)
  token = current_token
  if (token.kind == kind)
    @lexer.advance
    return token
  end

  raise TSJSONSyntaxError.syntax_error(
          @lexer.source,
          token.start_pos,
          "Expected #{LexerUtils.get_token_kind_desc(kind)}, found #{
            LexerUtils.get_token_desc(token)
          }."
        )
end

#loc(start_token) ⇒ Object

Returns a location object, used to identify the place in the source that created a given parsed object.



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# File 'lib/language/parser/parser.rb', line 362

def loc(start_token)
  end_token = @lexer.last_token
  return {} #Location.new(start_token, end_token, @lexer.source)
end

#parse_definition ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 27

def parse_definition
  if (peek(TokenKind::NAME))
    case current_token.value
    when 'type'
      return parse_type_alias_definition
    when 'enum'
      return parse_enum_definition
    end
  end

  raise unexpected
end

#parse_document ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 13

def parse_document
  return(
    {
      kind: AST::Kind::Document,
      definitions:
        parse_optional_many(
          TokenKind::SOF,
          :parse_definition,
          TokenKind::EOF
        )
    }
  )
end

#parse_enum_definition ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 308

def parse_enum_definition
  start = expect_token(TokenKind::NAME)
  name = parse_name
  members =
    parse_many(
      TokenKind::BRACE_L,
      :parse_enum_member,
      TokenKind::BRACE_R,
      TokenKind::COMMA
    )
  expect_optional_token(TokenKind::SEMICOLON)

  return(
    { kind: AST::Kind::Enum, name: name, members: members, loc: loc(start) }
  )
end

#parse_enum_member ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 325

def parse_enum_member
  start = current_token
  name = parse_name

  value = nil
  value = parse_string_literal if (expect_optional_token(TokenKind::EQUALS))

  return(
    {
      kind: AST::Kind::EnumMember,
      name: name,
      value: value,
      loc: loc(start)
    }
  )
end

#parse_float ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 225

def parse_float()
  token = expect_token(TokenKind::FLOAT)
  return(
    { kind: AST::Kind::Float, value: token.value.to_f, loc: loc(token) }
  )
end

#parse_int ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 220

def parse_int()
  token = expect_token(TokenKind::INT)
  return { kind: AST::Kind::Int, value: token.value.to_i, loc: loc(token) }
end

#parse_many(open_kind, parse_fn_symbol, close_kind, delimeter_kind = nil) ⇒ Object

Returns a non-empty list of parse nodes, determined by the parseFn. This list begins with a lex token of openKind and ends with a lex token of closeKind. Advances the parser to the next lex token after the closing token.



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# File 'lib/language/parser/parser.rb', line 375

def parse_many(open_kind, parse_fn_symbol, close_kind, delimeter_kind = nil)
  expect_token(open_kind)
  nodes = []
  loop do
    nodes.push(self.send(parse_fn_symbol))
    expect_token(delimeter_kind) if (delimeter_kind && !peek(close_kind))
    break if expect_optional_token(close_kind)
  end
  return nodes
end

#parse_name ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 75

def parse_name
  token = expect_token(TokenKind::NAME)
  return { kind: AST::Kind::Name, value: token.value, loc: loc(token) }
end

#parse_operation ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 140

def parse_operation
  expect_optional_token(TokenKind::PIPE)
  nodes = [parse_type_definition]
  operations = []

  execute_operation =
    lambda do
      operation = operations.shift
      right = nodes.pop
      left = nodes.pop

      new_operation = nil
      if (operation == TokenKind::AMP)
        if (left[:kind] == AST::Kind::IntersectionType)
          new_operation = {
            kind: AST::Kind::IntersectionType,
            types: left[:types].concat([right])
          }
        else
          new_operation = {
            kind: AST::Kind::IntersectionType,
            types: [left, right]
          }
        end
      elsif (operation == TokenKind::PIPE)
        if (left[:kind] == AST::Kind::UnionType)
          new_operation = {
            kind: AST::Kind::UnionType,
            types: left[:types].concat([right])
          }
        else
          new_operation = {
            kind: AST::Kind::UnionType,
            types: [left, right]
          }
        end
      end
      nodes.push(new_operation)
    end

  operation_kind = nil
  loop do
    unless (
             LexerUtils.is_operation_token(
               (operation_kind = current_token.kind)
             )
           )
      break
    end
    loop do
      unless (
               operations.length > 0 &&
                 TokenKind.operation_precedence(operations[0]) >=
                   TokenKind.operation_precedence(operation_kind)
             )
        break
      end
      execute_operation.call
    end

    operations.unshift(operation_kind)
    @lexer.advance
    nodes.push(parse_type_definition)
  end

  loop do
    break unless (operations.length > 0)
    execute_operation.call
  end

  return nodes[0]
end

#parse_optional_many(open_kind, parse_fn_symbol, close_kind, delimeter_kind = nil) ⇒ Object

Returns a list of parse nodes, determined by the parseFn. It can be empty only if open token is missing otherwise it will always return non-empty list that begins with a lex token of openKind and ends with a lex token of closeKind. Advances the parser to the next lex token after the closing token.



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# File 'lib/language/parser/parser.rb', line 390

def parse_optional_many(
  open_kind,
  parse_fn_symbol,
  close_kind,
  delimeter_kind = nil
)
  if (expect_optional_token(open_kind))
    nodes = []
    loop do
      break if expect_optional_token(close_kind)
      nodes.push(self.send(parse_fn_symbol))
      expect_token(delimeter_kind) if (delimeter_kind && !peek(close_kind))
    end
    return nodes
  end
  return []
end

#parse_parenthesized_type ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 301

def parse_parenthesized_type()
  start = expect_token(TokenKind::PAREN_L)
  type = parse_operation
  expect_token(TokenKind::PAREN_R)
  return { kind: AST::Kind::ParenthesizedType, type: type, loc: loc(start) }
end

#parse_property_signature ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 282

def parse_property_signature()
  start = current_token
  name = parse_name
  optional = expect_optional_token(TokenKind::QUESTION_MARK).nil?.!
  expect_token(TokenKind::COLON)
  type = parse_operation
  expect_token(TokenKind::SEMICOLON)

  return(
    {
      kind: AST::Kind::PropertySignature,
      name: name,
      type: type,
      optional: optional,
      loc: loc(start)
    }
  )
end

#parse_string_literal ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 213

def parse_string_literal()
  token = expect_token(TokenKind::STRING)
  return(
    { kind: AST::Kind::StringLiteral, value: token.value, loc: loc(token) }
  )
end

#parse_tuple ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 253

def parse_tuple
  start = current_token
  types =
    parse_many(
      TokenKind::BRACKET_L,
      :parse_type_definition,
      TokenKind::BRACKET_R,
      TokenKind::COMMA
    )
  return { kind: AST::Kind::Tuple, types: types, loc: loc(start) }
end

#parse_type_alias_definition ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 40

def parse_type_alias_definition
  start = expect_token(TokenKind::NAME)

  name = parse_name
  parameters =
    parse_optional_many(
      TokenKind::CHEVRON_L,
      :parse_type_parameter,
      TokenKind::CHEVRON_R,
      TokenKind::COMMA
    )

  expect_token(TokenKind::EQUALS)
  definition = parse_operation

  expect_optional_token(TokenKind::SEMICOLON)

  return(
    {
      kind: AST::Kind::TypeAlias,
      name: name,
      parameters: parameters,
      definition: definition,
      loc: loc(start)
    }
  )
end

#parse_type_definition ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 80

def parse_type_definition()
  start = current_token
  type = nil
  if (peek(TokenKind::NAME))
    type = parse_type_reference
  elsif (peek(TokenKind::BRACE_L))
    type = parse_type_literal
  elsif (peek(TokenKind::PAREN_L))
    type = parse_parenthesized_type
  elsif (peek(TokenKind::BRACKET_L))
    type = parse_tuple
  elsif (peek(TokenKind::STRING))
    type = parse_string_literal
  elsif (peek(TokenKind::INT))
    type = parse_int
  elsif (peek(TokenKind::FLOAT))
    type = parse_float
  end

  throw unexpected if (!type)

  loop do
    unless [TokenKind::BRACKET_L, TokenKind::DOT].include?(
             current_token.kind
           )
      break
    end

    if (expect_optional_token(TokenKind::BRACKET_L))
      if (expect_optional_token(TokenKind::BRACKET_R))
        type = { kind: AST::Kind::ArrayType, type: type, loc: loc(start) }
      else
        index = parse_string_literal
        expect_token(TokenKind::BRACKET_R)
        type = {
          kind: AST::Kind::IndexAccess,
          target: type,
          index: index,
          loc: loc(start)
        }
      end
    elsif (expect_optional_token(TokenKind::DOT))
      property = parse_name
      type = {
        kind: AST::Kind::PropertyAccess,
        target: type,
        property: property,
        loc: loc(start)
      }
    end
  end

  if (expect_optional_token(TokenKind::BRACKET_L))
    expect_token(TokenKind::BRACKET_R)
    type = { kind: AST::Kind::ArrayType, type: type, loc: loc(start) }
  end

  return type
end

#parse_type_literal ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 265

def parse_type_literal
  start = current_token
  properties =
    parse_optional_many(
      TokenKind::BRACE_L,
      :parse_property_signature,
      TokenKind::BRACE_R
    )
  return(
    {
      kind: AST::Kind::TypeLiteral,
      properties: properties,
      loc: loc(start)
    }
  )
end

#parse_type_parameter ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 68

def parse_type_parameter
  start = current_token
  name = parse_name

  return { kind: AST::Kind::TypeParameter, name: name, loc: loc(start) }
end

#parse_type_reference ⇒ Object 



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# File 'lib/language/parser/parser.rb', line 232

def parse_type_reference
  start = current_token
  name = parse_name
  args =
    parse_optional_many(
      TokenKind::CHEVRON_L,
      :parse_operation,
      TokenKind::CHEVRON_R,
      TokenKind::COMMA
    )

  return(
    {
      kind: AST::Kind::TypeReference,
      name: name,
      args: args,
      loc: loc(start)
    }
  )
end

#peek(kind) ⇒ Object

Determines if the next token is of a given kind



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# File 'lib/language/parser/parser.rb', line 368

def peek(kind)
  current_token.kind == kind
end

#unexpected(at_token = nil) ⇒ Object

Helper function for creating an error when an unexpected lexed token is encountered.



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# File 'lib/language/parser/parser.rb', line 350

def unexpected(at_token = nil)
  token = at_token || current_token
  return(
    TSJSONSyntaxError.syntax_error(
      @lexer.source,
      token.start_pos,
      "Unexpected #{LexerUtils.get_token_desc(token)}."
    )
  )
end