コード例 #1
0
ファイル: Lexer.cs プロジェクト: Hyosya/Yoron
 /// <summary>
 /// 変数名を決めるための条件
 /// </summary>
 /// <param name="c"></param>
 /// <returns></returns>
 private static bool IdentifierTake(char c)
 {
     return(!Assign.IsMatch(c) &&
            !EndOfLine.IsMatch(c.ToString()) &&
            !LeftParenthesis.IsMatch(c) &&
            !RightParenthesis.IsMatch(c) &&
            c != ' ' &&
            c != '\t');
 }
コード例 #2
0
ファイル: Lexer.cs プロジェクト: Hyosya/Yoron
        /// <summary>
        /// ソースコードを解析してトークン列を生成
        /// </summary>
        /// <param name="targets"></param>
        /// <returns></returns>
        private static IEnumerable <Token> Analysis(string targets)
        {
            if (targets.EndsWith(";") == false || targets.EndsWith("\r\n") == false)
            {
                targets += "\r\n";
            }
            while (targets.Length > 0)
            {
                //スペースとタブは変換しない
                if (targets[0] == ' ' || targets[0] == '\t')
                {
                    targets = targets.Remove(0, 1);
                    continue;
                }

                if (targets[0] == '\"')
                {
                    var literal = targets
                                  .Skip(1)
                                  .TakeWhile(c => c != '\"')
                                  .Aggregate(new StringBuilder(), (sb, c) => sb.Append(c))
                                  .ToString();
                    targets = targets.Remove(0, literal.Length + 2);
                    yield return(new StringLiteral(literal));

                    continue;
                }

                if (LeftParenthesis.IsMatch(targets[0]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new LeftParenthesis());

                    continue;
                }

                if (RightParenthesis.IsMatch(targets[0]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new RightParenthesis());

                    continue;
                }

                if (BlockBegin.IsMatch(targets[0]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new BlockBegin());

                    continue;
                }

                if (BlockEnd.IsMatch(targets[0]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new BlockEnd());

                    continue;
                }

                if (targets.StartsWith("Writeln"))
                {
                    targets = targets.Remove(0, 7);
                    yield return(new StandardOutput());

                    continue;
                }

                if (targets.StartsWith("Readln()"))
                {
                    targets = targets.Remove(0, 8);
                    yield return(new StandardInput());

                    continue;
                }

                if (Int32Literal.SpecifiedCollection.Contains(targets[0]))
                {
                    var value = targets.TakeWhile(c => Int32Literal.SpecifiedCollection.Contains(c)).ToArray();
                    targets = targets.Remove(0, value.Length);
                    yield return(new Int32Literal(new string(value)));

                    continue;
                }

                if (EndOfLine.IsMatch(targets[0].ToString()) || EndOfLine.IsMatch(new string(targets.Take(2).ToArray())))
                {
                    var value = targets.TakeWhile(i => i == ';' || i == '\r' || i == '\n').Count();
                    targets = targets.Remove(0, value);
                    yield return(new EndOfLine());

                    continue;
                }

                if (targets.Length > 1 && Assign.IsMatch(targets[0]) && !Assign.IsMatch(targets[1]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new Assign());

                    continue;
                }

                if (targets.Length > 1 && AddAssign.IsMatch(targets[0], targets[1]))
                {
                    targets = targets.Remove(0, 2);
                    yield return(new AddAssign());

                    continue;
                }

                if (targets.StartsWith("var "))
                {
                    var varVariableName = targets.Skip(4)
                                          .TakeWhile(c => c != ' ' && c != '\t' && c != '=')
                                          .Aggregate(new StringBuilder(), (sb, c) => sb.Append(c))
                                          .ToString();
                    if (!(JudgeWord(varVariableName) is Identifier))
                    {
                        throw new Exception("変数にキーワードが使われています。");
                    }
                    targets = targets.Remove(0, 4 + varVariableName.Length);
                    yield return(new VarDeclaration(varVariableName));

                    continue;
                }

                if (PlusOperator.IsMatch(targets[0]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new PlusOperator());

                    continue;
                }

                if (MinusOperator.IsMatch(targets[0]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new MinusOperator());

                    continue;
                }

                if (MultiplyOperator.IsMatch(targets[0]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new MultiplyOperator());

                    continue;
                }

                if (DivideOperator.IsMatch(targets[0]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new DivideOperator());

                    continue;
                }

                if (ModuloOperator.IsMatch(targets[0]))
                {
                    targets = targets.Remove(0, 1);
                    yield return(new ModuloOperator());

                    continue;
                }

                if (targets.Length > 1 && targets[0] == '=' && targets[1] == '=')
                {
                    targets = targets.Remove(0, 2);
                    yield return(new EqualOperator());

                    continue;
                }

                if (targets.Length > 1 && targets[0] == '!' && targets[1] == '=')
                {
                    targets = targets.Remove(0, 2);
                    yield return(new NotEqualOperator());

                    continue;
                }

                if (targets.Length > 1 && targets[0] == '>')
                {
                    if (targets[1] == '=')
                    {
                        targets = targets.Remove(0, 2);
                        yield return(new GreaterThanOrEqualOperator());

                        continue;
                    }
                    targets = targets.Remove(0, 1);
                    yield return(new GreaterThanOperator());

                    continue;
                }

                if (targets.Length > 1 && targets[0] == '<')
                {
                    if (targets[1] == '=')
                    {
                        targets = targets.Remove(0, 2);
                        yield return(new LessThanOrEqualOperator());

                        continue;
                    }
                    targets = targets.Remove(0, 1);
                    yield return(new LessThanOperator());

                    continue;
                }

                if (targets.Length > 1 && targets[0] == '&' && targets[1] == '&')
                {
                    targets = targets.Remove(0, 2);
                    yield return(new AndAlsoOperator());

                    continue;
                }

                if (targets.Length > 1 && targets[0] == '|' && targets[1] == '|')
                {
                    targets = targets.Remove(0, 2);
                    yield return(new OrElseOperator());

                    continue;
                }

                var word = targets.TakeWhile(IdentifierTake)
                           .Aggregate(new StringBuilder(), (sb, c) => sb.Append(c))
                           .ToString();
                if (word.Length == 0)
                {
                    throw new Exception("変数名なのに文字数がゼロ");
                }
                targets = targets.Remove(0, word.Length);
                yield return(JudgeWord(word));
            }
        }