/// <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');
}
/// <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));
}
}