diff --git a/MicroJava Compiler/src/ssw/mj/impl/Scanner.java b/MicroJava Compiler/src/ssw/mj/impl/Scanner.java
index 1b2ac66..898bd3e 100644
--- a/MicroJava Compiler/src/ssw/mj/impl/Scanner.java	
+++ b/MicroJava Compiler/src/ssw/mj/impl/Scanner.java	
@@ -1,15 +1,15 @@
 package ssw.mj.impl;
 
 import ssw.mj.Errors;
+import ssw.mj.Interpreter;
 import ssw.mj.scanner.Token;
 
 import java.io.IOException;
 import java.io.Reader;
-import java.util.HashMap;
 import java.util.Map;
-import java.util.Optional;
 
 import static ssw.mj.scanner.Token.Kind.*;
+import static ssw.mj.scanner.Token.Kind.number;
 
 public class Scanner {
 
@@ -112,40 +112,60 @@ public class Scanner {
 		}
 
 		if (isDigit(ch)) {
-			final var number = readNumber();
+			final var stringNumber = readNumber();
 
-			var token = new Token(Token.Kind.number, ogLine, ogCol);
-			token.numVal = number;
-			token.val = number + "";
+			try {
+				final var number = Integer.parseInt(stringNumber);
 
-			return token;
+				var token = new Token(Token.Kind.number, ogLine, ogCol);
+				token.numVal = number;
+				token.val = stringNumber;
+
+				return token;
+			} catch (NumberFormatException exception) {
+				final var token = new Token(number, ogLine, ogCol);
+				error(token, Errors.Message.BIG_NUM, stringNumber);
+				return token;
+			}
 		}
 
 		if (ch == '\'') {
 			nextCh();
 
+			if (ch == '\r') {
+				nextCh();
+			}
+
+			var charContent = ch;
+			var lfEscaped = false;
+			var tickEscaped = false;
+
 			if (ch == '\\') {
 				nextCh();
-				final var charContent = switch (ch) {
+				charContent = switch (ch) {
 					case 'n' -> '\n';
 					case 'r' -> '\r';
 					case 't' -> '\t';
 					case '\\' -> '\\';
 					case '\'' -> '\'';
-					default -> ' ';
+					default -> '\0';
 				};
 
-				final var token = new Token(charConst, ogLine, ogCol);
-				token.val = charContent + "";
-				token.numVal = charContent;
-				nextCh();
-				nextCh();
-				return token;
+				if (charContent == '\n') {
+					lfEscaped = true;
+				}
+
+				if (charContent == '\'') {
+					tickEscaped = true;
+				}
+
+				if (charContent == '\0') {
+					final var token = new Token(charConst, ogLine, ogCol);
+					error(token, Errors.Message.UNDEFINED_ESCAPE, ch);
+				}
 			}
 
-			final var charContent = ch;
-
-			if (charContent == LF || charContent == EOF || charContent == '\'') {
+			if (charContent == LF && !lfEscaped || charContent == EOF || charContent == '\'' && !tickEscaped) {
 				final var token = new Token(charConst, ogLine, ogCol);
 				final var message = switch (charContent) {
 					case LF -> Errors.Message.ILLEGAL_LINE_END;
@@ -191,14 +211,19 @@ public class Scanner {
 			case '.' -> new Token(Token.Kind.period, ogLine, ogCol);
 			case '{' -> new Token(Token.Kind.lbrace, ogLine, ogCol);
 			case '}' -> new Token(Token.Kind.rbrace, ogLine, ogCol);
+			case '[' -> new Token(Token.Kind.lbrack, ogLine, ogCol);
+			case ']' -> new Token(Token.Kind.rbrack, ogLine, ogCol);
+			case '(' -> new Token(Token.Kind.lpar, ogLine, ogCol);
+			case ')' -> new Token(Token.Kind.rpar, ogLine, ogCol);
 			case (char) -1 -> new Token(Token.Kind.eof, ogLine, ogCol);
+			case '~' -> new Token(Token.Kind.tilde, ogLine, ogCol);
 			case '=' -> {
 				if (ch == '=') {
 					nextCh();
 					yield new Token(Token.Kind.eql, ogLine, ogCol);
 				}
 
-				yield new Token(Token.Kind.assign, line, col);
+				yield new Token(Token.Kind.assign, ogLine, ogCol);
 			}
 			case '+' -> {
 				if (ch == '=') {
@@ -240,6 +265,18 @@ public class Scanner {
 					yield new Token(Token.Kind.slashas, ogLine, ogCol);
 				}
 
+				if (ch == '*') {
+					nextCh();
+					final var success = skipComment();
+					if (success) {
+						yield next();
+					} else {
+						final var token = new Token(eof, ogLine, ogCol);
+						error(token, Errors.Message.EOF_IN_COMMENT);
+						yield next();
+					}
+				}
+
 				yield new Token(Token.Kind.slash, ogLine, ogCol);
 			}
 			case '%' -> {
@@ -256,8 +293,9 @@ public class Scanner {
 					yield new Token(Token.Kind.neq, ogLine, ogCol);
 				}
 
-				error(new Token(none, line, col), Errors.Message.INVALID_CHAR);
-				yield next();
+				final var token = new Token(none, ogLine, ogCol);
+				error(token, Errors.Message.INVALID_CHAR, ogChar);
+				yield token;
 			}
 			case '>' -> {
 				if (ch == '=') {
@@ -268,7 +306,7 @@ public class Scanner {
 				yield new Token(Token.Kind.gtr, ogLine, ogCol);
 			}
 			case '<' -> {
-				if (ch == '<') {
+				if (ch == '=') {
 					nextCh();
 					yield new Token(Token.Kind.leq, ogLine, ogCol);
 				}
@@ -281,21 +319,24 @@ public class Scanner {
 					yield new Token(Token.Kind.and, ogLine, ogCol);
 				}
 
-				error(new Token(none, line, col), Errors.Message.INVALID_CHAR);
-				yield next();
+				final var token = new Token(none, ogLine, ogCol);
+				error(token, Errors.Message.INVALID_CHAR, ogChar);
+				yield token;
 			}
 			case '|' -> {
 				if (ch == '|') {
 					nextCh();
-					yield new Token(Token.Kind.and, ogLine, ogCol);
+					yield new Token(Token.Kind.or, ogLine, ogCol);
 				}
 
-				error(new Token(none, line, col), Errors.Message.INVALID_CHAR);
-				yield next();
+				final var token = new Token(none, ogLine, ogCol);
+				error(token, Errors.Message.INVALID_CHAR, ogChar);
+				yield token;
 			}
 			default -> {
-				error(new Token(none, line, col), Errors.Message.INVALID_CHAR);
-				yield next();
+				final var token = new Token(none, ogLine, ogCol);
+				error(token, Errors.Message.INVALID_CHAR, ogChar);
+				yield token;
 			}
 		};
 	}
@@ -333,7 +374,7 @@ public class Scanner {
 	public String readName() {
 		final var builder = new StringBuilder();
 
-		while (isLetter(ch)) {
+		while (isLetter(ch) || ch == '_' || isDigit(ch)) {
 			builder.append(ch);
 			nextCh();
 		}
@@ -341,7 +382,7 @@ public class Scanner {
 		return builder.toString();
 	}
 
-	public int readNumber() {
+	public String readNumber() {
 		final var builder = new StringBuilder();
 
 		while (isDigit(ch)) {
@@ -349,7 +390,7 @@ public class Scanner {
 			nextCh();
 		}
 
-		return Integer.parseInt(builder.toString());
+		return builder.toString();
 	}
 
 	private Token getTokenByName(String name, int line, int col) {
@@ -364,6 +405,30 @@ public class Scanner {
 		return token;
 	}
 
+	private boolean skipComment() {
+		var commentCount = 1;
+		while (commentCount != 0) {
+			final var lastCh = ch;
+			nextCh();
+
+			if (lastCh == '/' && ch == '*') {
+				commentCount++;
+				nextCh();
+			}
+
+			if (lastCh == '*' && ch == '/') {
+				commentCount--;
+				nextCh();
+			}
+
+			if (ch == EOF && commentCount != 0) {
+				return false;
+			}
+		}
+
+		return true;
+	}
+
 	// ================================================
 	// ================================================
 }