larkdown/Parser/Lexer/LineStartState.cs

using System;
using System.Collections.Generic;
using System.Text;
using System.Text.RegularExpressions;

namespace Larkdown.Parser.Lexer
{
	class LineStartState : State
	{
		public override State Next(Lexer lexer)
		{
			var indent = lexer.Read(new Regex("^[\t ]*"));
			if (indent.Length > 0)
			{
				lexer.Emit(new Token(TokenType.Indentation, indent));
			}

			if (lexer.IsEof())
			{
				lexer.Emit(new Token(TokenType.Eof));
				return null;
			}

			switch (lexer.Peek())
			{
				case '\n':
					lexer.Emit(new Token(TokenType.Empty));
					lexer.Read();
					return this;

				default:
					return new TextState();
			}
		}
	}
}