using System;
using System.Collections.Generic;
namespace sharp.parser
{
	public class Lexer
	{
		List<TokenDefinition> tokenDefinitions = new List<TokenDefinition>();

		public Lexer(){
		}
		public Lexer(TokenDefinition[] tokenDefinitions)
		{
			this.tokenDefinitions.AddRange(tokenDefinitions);
		}

		public void AddTokenDefinition(TokenDefinition tokenDefinition)
		{
			this.tokenDefinitions.Add(tokenDefinition);
		}
		public void RemoveTokenDefinition(TokenDefinition tokenDefinition)
		{
			this.tokenDefinitions.Remove(tokenDefinition);
		}


		public Token[] parse(CharBuffer buffer){
			List<Token> tokens = new List<Token>();

			while (!buffer.EndOfBuffer()){
				Token t = null;

				foreach (TokenDefinition tdef in tokenDefinitions)
				{
					t = tdef.tryParse(buffer);
					if (t != null)
					{
						break;
					}
				}

				if (t == null)
				{
					break;
				}

				tokens.Add(t);
			}

			if (!buffer.EndOfBuffer())
			{
				throw new FormatException(String.Format("Unexpected character at line {0} position {1}. '{2}'", buffer.CurrentLineNumber, buffer.CurrentLinePosition, buffer.Current));
			}
			return tokens.ToArray();
		}



	}
}