diff --git a/Suslang/Suslang.cs b/Suslang/Suslang.cs
index 7ccd1f8..4b448ff 100644
--- a/Suslang/Suslang.cs
+++ b/Suslang/Suslang.cs
@@ -20,6 +20,7 @@ public enum TokenType {
     Asterisk,
     Slash,
     Percent,
+    Dot,
 }
 
 public struct Position {
@@ -46,6 +47,10 @@ public class Lexer {
     public Token next() {
         if (done()) {
             return token(TokenType.Eof, position());
+        } else if (" \t\r\n".Contains(current())) {
+            while (!done() && " \t\r\n".Contains(current()))
+                step();
+            return next();
         } else if ("123456789".Contains(current())) {
             return intToken();
         } else if ("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_".Contains(current())) {
@@ -57,31 +62,31 @@ public class Lexer {
 
     private Token intToken() {
         var start = position();
-        var value = "";
-        value += current();
         step();
-        while (!done() && "1234567890".Contains(current())) {
-            value += current();
+        while (!done() && "1234567890".Contains(current()))
             step();
-        }
         return token(TokenType.Int, start);
     }
 
     private Token idToken() {
         var start = position();
-        var value = "";
-        value += current();
         step();
-        while (!done() && "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_".Contains(current())) {
-            value += current();
+        while (!done() && "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_".Contains(current()))
             step();
-        }
-        return token(TokenType.Id, start);
+        this.text.Substring(start.index, this.i - start.index).switch {
+            "false" => token(TokenType.False, start),
+            "true" => token(TokenType.True, start),
+            _ => token(TokenType.Id, start),
+        };
     }
 
     private Token staticToken() {
         var start = position();
         switch (current()) {
+            case '0':
+                break;
+            case '.':
+                break;
             case '(':
                 step();
                 return token(TokenType.LParen, start);
@@ -109,6 +114,32 @@ public class Lexer {
         }
     }
 
+    private Token zeroToken() {
+        var start = position();
+        step();
+        if (!done() && (current() == 'x' || current() == 'X')) {
+            while (!done() && "1234567890abcdefABCDEF".Contains(current())) 
+                step();
+            return token(TokenType.Hex, start);
+        } else {
+            while (!done() && "1234567890".Contains(current())) 
+                step();
+            return token(TokenType.Int, start);
+        }
+    }
+    
+    private Token dotToken() {
+        var start = position();
+        step();
+        if (!done() && "1234567890".Contains(current())) {
+            while (!done() && "1234567890".Contains(current())) 
+                step();
+            return token(TokenType.Decimal, start);
+        } else {
+            return token(TokenType.Dot, start);
+        }
+    }
+
     private Token token(TokenType type, Position start) => new Token() {
         type = type,
         position = start,
@@ -130,16 +161,240 @@ public class Lexer {
 }
 
 public interface Expr {
+    string astString(int depth);
+}
 
+public ErrorExpr : Expr {
+    public Position position;
+    public string message;
+
+    public override astString(int depth) =>
+        $"ErrorExpr {{ {this.position.line}:{this.position.col} \"{this.message}\" }}";
+}
+
+public IdExpr : Expr {
+    public string value;
+
+    public override astString(int depth) =>
+        $"IdExpr {{ \"{this.value}\" }}";
+}
+
+public IntExpr : Expr {
+    public int value;
+
+    public override astString(int depth) =>
+        $"IntExpr {{ {this.value} }}";
+}
+
+public FloatExpr : Expr {
+    public double value;
+
+    public override astString(int depth) =>
+        $"FloatExpr {{ {this.value} }}";
+}
+
+public StringExpr : Expr {
+    public string value;
+
+    public override astString(int depth) =>
+        $"FloatExpr {{ \"{this.value}\" }}";
+}
+
+public BoolExpr : Expr {
+    public bool value;
+
+    public override astString(int depth) =>
+        $"BoolExpr {{ {this.value} }}";
+}
+
+public enum UnaryType {
+    Not,
+    Negate,
+}
+
+public UnaryExpr : Expr {
+    public UnaryType type;
+    public Expr value;
+
+    public override astString(int depth) =>
+        $"UnaryExpr {{\n{new String(' ', depth) + 1}type: "
+        + $"{this.type.ToString()},\n{new String(' ', depth + 1)}value: "
+        + $"{this.value.astString(depth + 1)}\n{new String(' ', depth)}}}";
+}
+
+public enum BinaryType {
+    Add,
+    Subtract,
+    Multiply,
+    Divide,
+    Modulus,
+}
+
+public BinaryExpr : Expr {
+    public BinaryType type;
+    public Expr left, right;
+
+    public override astString(int depth) =>
+        $"UnaryExpr {{\n{new String(' ', depth) + 1}type: "
+        + $"{this.type.ToString()},\n{new String(' ', depth + 1)}left: "
+        + $"{this.left.astString(depth + 1)},\n{new String(' ', depth + 1)}right: "
+        + $"{this.right.astString(depth + 1)}\n{new String(' ', depth)}}}";
 }
 
 public class Parser {
+    private int i = 0;
+    private string text;
+    private List<Token> tokens;
+
+    public Parser(string text, List<Token> tokens) {
+        this.text = text;
+        this.tokens = tokens;
+    }
+
     public Expr parseExpr() {
-        throw new NotImplementedException();
+        return parsePrec11();
+    }
+
+    public Expr parsePrec11() {
+        var left = parsePrec12();
+        if (!done() && current().type == TokenType.Plus) {
+            step();
+            var right = parsePrec11();
+            return new BinaryExpr() {
+                type = BinaryType.Add,
+                left = left,
+                right = right,
+            };
+        } else if (!done() && current().type == TokenType.Minus) {
+            step();
+            var right = parsePrec11();
+            return new BinaryExpr() {
+                type = BinaryType.Subtraction,
+                left = left,
+                right = right,
+            };
+        } else {
+            return left;
+        }
+    }
+
+    public Expr parsePrec12() {
+        var left = parsePrec13();
+        if (!done() && current().type == TokenType.Asterisk) {
+            step();
+            var right = parePrec12();
+            return new BinaryExpr() {
+                type = BinaryType.Multiply,
+                left = left,
+                right = right,
+            };
+        } else if (!done() && current().type == TokenType.Slash) {
+            step();
+            var right = parePrec12();
+            return new BinaryExpr() {
+                type = BinaryType.Divide,
+                left = left,
+                right = right,
+            };
+        } else if (!done() && current().type == TokenType.Percent) {
+            step();
+            var right = parePrec12();
+            return new BinaryExpr() {
+                type = BinaryType.Modulus,
+                left = left,
+                right = right,
+            };
+        } else {
+            return left;
+        }
+    }
+
+    public Expr parsePrec13() {
+        return parsePrec18();
+    }
+
+    public Expr parsePrec18() {
+        if (!done() && current().type == TokenType.LParen) {
+            step();
+            var expr = parseExpr();
+            if (done() || current().type TokenType.RParen) {
+                var pos = position();
+                step();
+                return new ErrorExpr() {
+                    position = pos,
+                    message = "expected ')'"
+                };
+            }
+            step();
+            return expr;
+        } else {
+            return parseOperand();
+        }
+    }
+
+    public parseOperand() {
+        var start = position();
+        if (done()) {
+            step();
+            return new ErrorExpr() {
+                position = start,
+                message = "expected value, got eof",
+            };
+        } else if (current().type == TokenType.Int) {
+            var intToken = current();
+            step();
+            if (!done() && current().type == TokenType.Decimal) {
+                var decimalToken = current();
+                step();
+                return new FloatExpr() {
+                    value = double.Parse(this.text.Substring(start.index, intToken.length + decimalToken.length)),
+                };
+            } else {
+                return new IntExpr() {
+                    value = int.Parse(this.text.Substring(start.index, intToken.length));
+                };
+            }
+        } else if (current().type == TokenType.String) {
+            var stringToken = current();
+            step();
+            return new StringExpr() {
+                value = this.text.Substring(start.index, stringToken.length),
+            };
+        } else if (current().type == TokenType.False) {
+            step();
+            return new BoolExpr() {
+                value = false,
+            };
+        } else if (current().type == TokenType.True) {
+            step();
+            return new BoolExpr() {
+                value = true,
+            };
+        } else {
+            step();
+            return new ErrorExpr() {
+                position = start,
+                message = "expected value",
+            };
+        }
+    }
+
+    private char current() => this.tokens[this.i];
+    private bool done() => this.i >= this.text.Length;
+
+    private void step() {
+        this.i += 1;
     }
 }
 
-public interface Operation {
+public interface Operation {}
+
+public class PushInt {
+    public int value;
+} 
+
+public class PushFloat {
+    public double value;
 }
 
 public class Compiler {