Module: Rucc::Parser::Enum

Included in:
Rucc::Parser
Defined in:
lib/rucc/parser/enum.rb

Instance Method Summary collapse

Instance Method Details

#read_enum_def ⇒ Type

Returns:



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# File 'lib/rucc/parser/enum.rb', line 5

def read_enum_def
  tag = nil
  tok = get

  # Enum is handled as a synonym for int. We only check if the enum
  # is declared.
  if tok.kind == T::IDENT
    tag = tok.sval
    tok = get
  end
  if tag
    ty = @tags[tag]
    if ty && ty.kind != Kind::ENUM
      Util.errort!(tok, "declarations of #{tag} does not match")
    end
  end
  if !Token.is_keyword?(tok, '{')
    if !tag || !@tags[tag]
      Util.errort!(tok, "enum tag #{tag} is not defined")
    end
    @lexer.unget_token(tok)
    return Type::INT
  end

  # NOTE: read enum declaration
  if tag
    @tags[tag] = Type::ENUM
  end

  val = 0
  while true
    tok = get
    if Token.is_keyword?(tok, '}')
      break
    end
    if tok.kind != T::IDENT
      Util.errort!(tok, "identifier expected, but got #{tok}")
    end
    name = tok.sval

    if next_token?('=')
      val = read_intexpr
    end
    constval = Node.ast_inttype(Type::INT, val)
    val += 1
    env[name] = constval
    if next_token?(',')
      next
    end
    if next_token?('}')
      break
    end
    Util.errort!(peek(), "',' or '}' expected, but got #{peek}")
  end

  Type::INT
end