diff --git a/CharBuffer.cs b/CharBuffer.cs
new file mode 100644
index 0000000..e03c41b
--- /dev/null
+++ b/CharBuffer.cs
@@ -0,0 +1,164 @@
+using System;
+using sharp.extensions;
+using System.Collections.Generic;
+using System.Linq;
+namespace sharp.parser
+{
+	public class CharBuffer
+	{
+		char[] chars;
+		int position;
+
+		int lineno, linepos, linestart;
+
+		int[] lineStarts;
+
+		public char[] Characters { get { return this.chars; } }
+
+		public CharBuffer(char[] source)
+		{
+			this.chars = source;
+			this.initialize();
+		}
+		public CharBuffer(string source){
+			this.chars = source.ToCharArray();
+			this.initialize();
+		}
+
+		private void initialize(){
+			this.lineno = 1;
+			this.linepos = 1;
+			this.linestart = 0;
+
+			List<int> lineStartList = new List<int>();
+			lineStartList.Add(0);
+
+			for (int n = 0; n < this.chars.Length;n++)
+			{
+				if (this.chars[n] == 0x0a){
+					lineStartList.Add(n);
+				}
+			}
+			lineStartList.Add(this.chars.Length);
+
+			this.lineStarts = lineStartList.ToArray();
+		}
+
+		private int lineEnd(){
+			int p = position;
+			while (this.chars[p]!='\n'){
+				p++;
+				if (p >= this.chars.Length){
+					break;
+				}
+			}
+			return p;
+		}
+
+		public string getLineAt(int pos){
+			int n;
+
+			if (pos >= this.chars.Length){
+				return null;
+			}
+
+			for (n = 0; n < this.lineStarts.Count();n++){
+				if (pos >= this.lineStarts[n]){
+					break;
+				}
+			}
+
+			return new string( this.chars.Segment(this.lineStarts[n],this.lineStarts[n+1]-this.lineStarts[n]) );
+		}
+
+		public int Position {
+			get { return position; }
+			set { this.position = value >= chars.Length ? chars.Length : value; }
+		}
+
+		public bool MoveNext(){
+			if (position < this.chars.Length){
+				position++;
+
+				this.linepos++;
+
+				if (Last == '\n'){
+					this.linepos = 1;
+					this.linestart = position;
+					this.lineno++;
+				}
+
+				return true;
+			}
+			return false;
+		}
+
+		public bool MoveBack(){
+			if (position > 0){
+				position--;
+				return true;
+			}
+			return false;
+		}
+
+		public bool EndOfBuffer(){
+			return (this.position >= this.chars.Length);
+		}
+
+		public void BypassWhiteSpace(){
+			while (Current <= 0x20){
+				MoveNext();
+			}
+		}
+
+		public int CurrentLineNumber { get { return this.lineno; } }
+		public int CurrentLinePosition { get { return this.linepos; } }
+
+		public string CurrentLine { get { return new String(this.chars.Segment(this.linestart,lineEnd()-this.linestart)); } }
+
+		public char Last { 
+			get { 
+				if (position > 0) {
+					return this.chars[position - 1]; 
+				};
+				throw new IndexOutOfRangeException("No character before the first one");
+			}
+		}
+		public char Current
+		{
+			get {
+				if (position < this.chars.Length){
+					return this.chars[position];
+				}
+				throw new IndexOutOfRangeException("No character after the last one");
+			}
+		}
+		public char Next
+		{
+			get {
+				if (position < this.chars.Length-1) {
+					return this.chars[position + 1]; 
+				};
+				throw new IndexOutOfRangeException("No character after the last one");
+
+			}
+		}
+
+		public string Following(int len)
+		{
+			return new string(this.chars.Segment(position, len));
+		}
+		public string Preceding(int len)
+		{
+			return new string(this.chars.Segment(position-len, len));
+		}
+
+		public void Pass(char ch){
+			if (Current != ch){
+				throw new ParserFormatException(String.Format("Expected {0}, but got {1}",ch,Current),lineno,linepos,CurrentLine);
+			}
+			MoveNext();
+		}
+
+	}
+}
diff --git a/CharGroup.cs b/CharGroup.cs
new file mode 100644
index 0000000..9cc6afa
--- /dev/null
+++ b/CharGroup.cs
@@ -0,0 +1,77 @@
+using System;
+using sharp.extensions;
+namespace sharp.parser
+{
+	public class CharGroup
+	{
+		public static readonly CharGroup digit = new CharGroup('0', '9');
+		public static readonly CharGroup zero = new CharGroup('0');
+		public static readonly CharGroup digit19 = new CharGroup('1', '9');
+		public static readonly CharGroup plusminus = new CharGroup(new char[] { '+', '-' });
+		public static readonly CharGroup minus = new CharGroup(new char[] { '+', '-' });
+		public static readonly CharGroup plus = new CharGroup(new char[] { '+' });
+		public static readonly CharGroup az = new CharGroup('a','z');
+		public static readonly CharGroup AZ = new CharGroup('A','Z');
+		public static readonly CharGroup aAzZ = az + AZ;
+		public static readonly CharGroup LF = new CharGroup((char)0x0A);
+		public static readonly CharGroup CR = new CharGroup((char)0x0D);
+		public static readonly CharGroup HTAB = new CharGroup((char)0x09);
+		public static readonly CharGroup WS = new CharGroup(new char[] { (char)0x09, (char)0x0A, (char)0x0B, (char)0x0C, (char)0x0D, (char)0x20});
+		public static readonly CharGroup hexdigits = new CharGroup('a','f') + new CharGroup('A','F') + digit;
+
+		char[] chars;
+
+		public CharGroup(char ch)
+		{
+			chars = new char[] { ch };
+		}
+		public CharGroup(char[] chars)
+		{
+			this.chars = chars.Segment(0);
+		}
+		public CharGroup(char first,char last)
+		{
+			int l = (int)last - (int)first;
+			this.chars = new char[l+1];
+
+			for (int n = 0; n <= l;n++){
+				this.chars[n] = (char)(first + n);
+			}
+		}
+
+		public bool Contains(char ch){
+			foreach (char c in chars){
+				if (c == ch){
+					return true;
+				}
+			}
+			return false;
+		}
+
+		public bool Intersects(CharGroup other){
+			foreach (char ch in chars){
+				if (other.Contains(ch)){
+					return true;
+				}
+			}
+			return false;
+		}
+
+
+
+		public static CharGroup operator +(CharGroup cg1, CharGroup cg2)
+		{
+			return new CharGroup(cg1.chars.Combine(cg2.chars));
+		}
+
+		public static CharGroup operator -(CharGroup cg1, CharGroup cg2)
+		{
+			return new CharGroup(cg1.chars.Remove(cg2.chars));
+		}
+
+		public override string ToString()
+		{
+			return string.Format("[CharGroup '{0}']",new string(this.chars));
+		}
+	}
+}
diff --git a/Lexer.cs b/Lexer.cs
new file mode 100644
index 0000000..f1d5a59
--- /dev/null
+++ b/Lexer.cs
@@ -0,0 +1,59 @@
+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();
+		}
+
+
+
+	}
+}
diff --git a/LexerPathSegment.cs b/LexerPathSegment.cs
new file mode 100644
index 0000000..5fd63a8
--- /dev/null
+++ b/LexerPathSegment.cs
@@ -0,0 +1,148 @@
+using System;
+using System.Collections.Generic;
+namespace sharp.parser
+{
+	public class LexerPathSegment
+	{
+		public CharGroup CharGroup { get; private set; }
+		public bool MayFinish { get; set; }
+
+		public LexerPathSegment[] Followers { get { return followers.ToArray(); } }
+		private List<LexerPathSegment> followers = new List<LexerPathSegment>();
+
+		public LexerPathSegment(){
+			this.CharGroup = null;
+		}
+
+		public LexerPathSegment(LexerPathSegment follower)
+		{
+			this.CharGroup = null;
+			this.AddFollower(follower);
+		}
+
+		public LexerPathSegment(CharGroup charGroup)
+		{
+			this.CharGroup = charGroup;
+		}
+
+		public LexerPathSegment(char[] chars){
+			this.CharGroup = new CharGroup(chars);
+		}
+
+		public LexerPathSegment(char ch)
+		{
+			this.CharGroup = new CharGroup(ch);
+		}
+
+		public LexerPathSegment(char first,char last)
+		{
+			this.CharGroup = new CharGroup(first,last);
+		}
+
+		public LexerPathSegment(CharGroup charGroup,bool mayFinish)
+		{
+			this.CharGroup = charGroup;
+			this.MayFinish = mayFinish;
+		}
+
+		public LexerPathSegment(char[] chars,bool mayFinish)
+		{
+			this.CharGroup = new CharGroup(chars);
+			this.MayFinish = mayFinish;
+		}
+
+		public LexerPathSegment(char ch,bool mayFinish)
+		{
+			this.CharGroup = new CharGroup(ch);
+			this.MayFinish = mayFinish;
+		}
+
+		public LexerPathSegment(char first, char last,bool mayFinish)
+		{
+			this.CharGroup = new CharGroup(first, last);
+			this.MayFinish = mayFinish;
+		}
+
+		public LexerPathSegment(CharGroup charGroup, LexerPathSegment follower)
+		{
+			this.CharGroup = charGroup;
+			this.AddFollower(follower);
+		}
+
+		public LexerPathSegment(char[] chars, LexerPathSegment follower)
+		{
+			this.CharGroup = new CharGroup(chars);
+            this.AddFollower(follower);
+		}
+
+		public LexerPathSegment(char ch, LexerPathSegment follower)
+		{
+			this.CharGroup = new CharGroup(ch);
+            this.AddFollower(follower);
+		}
+
+		public LexerPathSegment(char first, char last, LexerPathSegment follower)
+		{
+			this.CharGroup = new CharGroup(first, last);
+            this.AddFollower(follower);
+		}
+
+
+
+		public void AddFollower(LexerPathSegment path, params LexerPathSegment[] paths)
+		{
+			AddFollower(path);
+			foreach (LexerPathSegment p in paths)
+			{
+				AddFollower(p);
+			}
+		}
+		public void AddFollower(LexerPathSegment path)
+		{
+			followers.Add(path);
+		}
+
+		public void RemoveFollower(LexerPathSegment path)
+		{
+			followers.Remove(path);
+		}
+
+		public int walk(CharBuffer buffer){
+
+			if (this.CharGroup == null){
+
+				foreach (LexerPathSegment next in followers){
+					int n = next.walk(buffer);
+					if (n > 0){
+						return n;
+					}
+				}
+
+				return -1;
+			}
+
+			if (MayFinish && buffer.EndOfBuffer()){
+				return 1;
+			}
+
+			if (this.CharGroup.Contains(buffer.Current)){
+				buffer.MoveNext();
+
+				foreach (LexerPathSegment next in followers){
+					int n = next.walk(buffer);
+					if (n > 0){
+						buffer.MoveBack();
+						return n + 1;
+					}
+				}
+				buffer.MoveBack();
+
+				if (MayFinish){
+					return 1;
+				}
+			}
+			return -1;
+		}
+
+	}
+}
diff --git a/Parser.cs b/Parser.cs
new file mode 100644
index 0000000..6f43337
--- /dev/null
+++ b/Parser.cs
@@ -0,0 +1,32 @@
+using System;
+using System.Collections.Generic;
+using System.Collections;
+
+namespace sharp.parser
+{
+	public abstract class Parser<T>
+	{
+		protected Lexer Lexer { get; private set; }
+
+		protected Parser(TokenDefinition[] tokenDefinitions)
+		{
+			this.Lexer = new Lexer(tokenDefinitions);
+		}
+
+		public Token[] Tokenize(char[] source){
+			return this.Lexer.parse(new CharBuffer(source));
+		}
+
+		public T Parse(string source){
+			return Parse(source.ToCharArray());
+		}
+
+		public T Parse(char[] source){
+			Token[] tokens = Tokenize(source);
+			return ParseTokens(tokens);
+		}
+
+		protected abstract T ParseTokens(Token[] tokens);
+
+	}
+}
diff --git a/ParserFormatException.cs b/ParserFormatException.cs
new file mode 100644
index 0000000..c3ca1ca
--- /dev/null
+++ b/ParserFormatException.cs
@@ -0,0 +1,18 @@
+using System;
+namespace sharp.parser
+{
+	public class ParserFormatException : Exception
+	{
+		public String Line { get; private set; }
+		public int LineNumber { get; private set; }
+		public int Position { get; private set; }
+
+		public ParserFormatException(string message,int lineno,int pos,string line)
+		:base(message)
+		{
+			Line = line;
+			LineNumber = lineno;
+			Position = pos;
+		}
+	}
+}
diff --git a/ParserPath.cs b/ParserPath.cs
new file mode 100644
index 0000000..3077571
--- /dev/null
+++ b/ParserPath.cs
@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+namespace sharp.parser
+{
+	public abstract class ParserPath
+	{
+		public ParserPath[] Followers { get { return followers.ToArray(); } }
+		private List<ParserPath> followers = new List<ParserPath>();
+
+		public ParserPath(){
+		}
+		public ParserPath(ParserPath[] followers)
+		{
+			this.followers.AddRange(followers);
+		}
+
+
+		public void AddFollower(ParserPath path,params ParserPath[] paths){
+			AddFollower(path);
+			foreach (ParserPath p in paths){
+				AddFollower(p);
+			}
+		}
+		public void AddFollower(ParserPath path)
+		{
+			followers.Add(path);
+		}
+
+		public void RemoveFollower(ParserPath path)
+		{
+			followers.Remove(path);
+		}
+
+
+
+	}
+}
diff --git a/ParserPathSegment.cs b/ParserPathSegment.cs
new file mode 100644
index 0000000..c815b5c
--- /dev/null
+++ b/ParserPathSegment.cs
@@ -0,0 +1,25 @@
+using System;
+namespace sharp.parser
+{
+	public class ParserPathSegment : ParserPath
+	{
+		public CharGroup CharGroup { get; private set; }
+
+		public ParserPathSegment(CharGroup charGroup)
+		{
+			this.CharGroup = charGroup;
+		}
+		public ParserPathSegment(char ch)
+		{
+			this.CharGroup = new CharGroup(ch);
+		}
+		public ParserPathSegment(char[] chars)
+		{
+			this.CharGroup = new CharGroup(chars);
+		}
+		public ParserPathSegment(char first, char last)
+		{
+			this.CharGroup = new CharGroup(first, last);
+		}
+	}
+}
diff --git a/Token.cs b/Token.cs
new file mode 100644
index 0000000..b8b8656
--- /dev/null
+++ b/Token.cs
@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using sharp.extensions;
+namespace sharp.parser
+{
+	public class Token
+	{
+		public TokenDefinition Definition { get; private set; }
+		public CharBuffer charBuffer;
+
+		public CharBuffer Buffer { get { return charBuffer; } }
+		public int Position { get; private set; }
+		public int Len { get; private set; } 
+
+		public string Value { get { return new String(charBuffer.Characters.Segment(Position, Len)); } }
+
+		public Token(TokenDefinition tdef,CharBuffer buffer,int len)
+		{
+			this.Definition = tdef;
+			this.charBuffer = buffer;
+			this.Position = buffer.Position;
+			this.Len = len;
+
+			buffer.Position += len;
+		}
+
+
+		public override string ToString()
+		{
+			return string.Format("[Token: {0} Value={1}]", Definition.Name, Value);
+		}
+
+	}
+}
diff --git a/TokenDefinition.cs b/TokenDefinition.cs
new file mode 100644
index 0000000..f1a9961
--- /dev/null
+++ b/TokenDefinition.cs
@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+namespace sharp.parser
+{
+	public class TokenDefinition
+	{
+		public String Name { get; private set; }
+		public LexerPathSegment[] PathHeads { get { return this.pathHeads.ToArray(); } }
+
+		private List<LexerPathSegment> pathHeads = new List<LexerPathSegment>();
+
+		public TokenDefinition(string name)
+		{
+			this.Name = name;
+		}
+		public TokenDefinition(string name,LexerPathSegment pathHead)
+		{
+			this.Name = name;
+			this.pathHeads.Add(pathHead);
+		}
+		public TokenDefinition(string name,LexerPathSegment[] pathHeads)
+		{
+			this.Name = name;
+            this.pathHeads.AddRange(pathHeads);
+		}
+
+
+		public Token tryParse(CharBuffer buffer){
+			int cpos = buffer.Position;
+
+			foreach (LexerPathSegment head in pathHeads){
+				int n = head.walk(buffer);
+				if (n > 0){
+					Token t = new Token(this,buffer,n);
+					return t;
+				}
+			}
+
+			return null;
+		}
+
+		public override string ToString()
+		{
+			return string.Format("[TokenDefinition: Name={0}]", Name);
+		}
+	}
+}
diff --git a/TokenQueue.cs b/TokenQueue.cs
new file mode 100644
index 0000000..b534f22
--- /dev/null
+++ b/TokenQueue.cs
@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+namespace sharp.parser
+{
+	public class TokenQueue : Queue<Token>
+	{
+		public TokenQueue()
+		{
+		}
+
+		public Token Expect(params TokenDefinition[] tdefs)
+		{
+			Token t = Dequeue();
+			foreach (TokenDefinition tdef in tdefs){
+				if (t.Definition == tdef)
+				{
+					return t;
+				}
+			}
+			throw new UnexpectedTokenException(t, tdefs);
+		}
+
+	}
+}
diff --git a/UnexpectedTokenException.cs b/UnexpectedTokenException.cs
new file mode 100644
index 0000000..fe865ac
--- /dev/null
+++ b/UnexpectedTokenException.cs
@@ -0,0 +1,18 @@
+using System;
+namespace sharp.parser
+{
+	public class UnexpectedTokenException : Exception
+	{
+		public Token Token { get; private set; }
+		public TokenDefinition[] Expected { get; private set; }
+
+		public new string Message { get; private set; }
+
+		public UnexpectedTokenException(Token token, TokenDefinition[] expected)
+		{
+			this.Token = token;
+			this.Expected = expected;
+			this.Message = string.Format("Unexpected Token in Line {0} at position {1}.\nGot {2} but should be one of [{3}]\nLine: {4}",0,token.Position,token.Value,string.Join<TokenDefinition>(",",expected),token.charBuffer.getLineAt(token.Position));
+		}
+	}
+}
diff --git a/sharp.parser.csproj b/sharp.parser.csproj
index 9084d52..0fb262c 100644
--- a/sharp.parser.csproj
+++ b/sharp.parser.csproj
@@ -4,10 +4,10 @@
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">x86</Platform>
     <ProjectGuid>{32267133-ADB7-4A85-8CF1-03CBDF53715C}</ProjectGuid>
-    <OutputType>Exe</OutputType>
+    <OutputType>Library</OutputType>
     <RootNamespace>sharp.parser</RootNamespace>
     <AssemblyName>sharp.parser</AssemblyName>
-    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v4.7</TargetFrameworkVersion>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x86' ">
     <DebugSymbols>true</DebugSymbols>
@@ -26,5 +26,28 @@
     <WarningLevel>4</WarningLevel>
     <PlatformTarget>x86</PlatformTarget>
   </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="Parser.cs" />
+    <Compile Include="CharGroup.cs" />
+    <Compile Include="TokenDefinition.cs" />
+    <Compile Include="ParserPath.cs" />
+    <Compile Include="CharBuffer.cs" />
+    <Compile Include="ParserFormatException.cs" />
+    <Compile Include="ParserPathSegment.cs" />
+    <Compile Include="Token.cs" />
+    <Compile Include="Lexer.cs" />
+    <Compile Include="LexerPathSegment.cs" />
+    <Compile Include="TokenQueue.cs" />
+    <Compile Include="UnexpectedTokenException.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\sharp-extensions\sharp.extensions.csproj">
+      <Project>{97CA3CA9-98B3-4492-B072-D7A5995B68E9}</Project>
+      <Name>sharp.extensions</Name>
+    </ProjectReference>
+  </ItemGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+  </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
 </Project>
\ No newline at end of file