diff --git a/src/main/java/edu/kit/typicalc/model/parser/TypeAssumptionParser.java b/src/main/java/edu/kit/typicalc/model/parser/TypeAssumptionParser.java
index bfcd7c8..3d9dca0 100644
--- a/src/main/java/edu/kit/typicalc/model/parser/TypeAssumptionParser.java
+++ b/src/main/java/edu/kit/typicalc/model/parser/TypeAssumptionParser.java
@@ -46,6 +46,7 @@ public class TypeAssumptionParser {
     }
 
     public Result<TypeAbstraction, ParseError> parseType(String type) {
+        // this parser is using the same lexer as the LambdaParser (to avoid types named "let" etc.)
         LambdaLexer lexer = new LambdaLexer(type);
         Result<Pair<Type, Integer>, ParseError> parsedType = parseType(lexer, 0);
         if (parsedType.isError()) {
@@ -66,11 +67,13 @@ public class TypeAssumptionParser {
             Result<Type, ParseError> typeResult = null;
             switch (t.getType()) {
                 case LEFT_PARENTHESIS:
+                    // recursive call, set number of open parentheses to 1
                     Result<Pair<Type, Integer>, ParseError> type2 = parseType(lexer, 1);
                     typeResult = type2.map(Pair::getLeft);
                     removedParens += type2.map(Pair::getRight).unwrapOr(1) - 1;
                     break;
                 case VARIABLE:
+                    // named type or type variable
                     type = parseLiteral(t.getText());
                     break;
                 case RIGHT_PARENTHESIS:
@@ -78,8 +81,10 @@ public class TypeAssumptionParser {
                     break;
                 case ARROW:
                     if (type == null) {
+                        // there was no type in front of the arrow
                         return new Result<>(null, ParseError.UNEXPECTED_TOKEN.withToken(t));
                     }
+                    // recursive call, keep open parentheses count
                     Result<Pair<Type, Integer>, ParseError> nextType = parseType(lexer, parenCount);
                     final Type left = type;
                     typeResult = nextType.map(Pair::getLeft).map(right -> new FunctionType(left, right));
@@ -90,19 +95,26 @@ public class TypeAssumptionParser {
                 default:
                     return new Result<>(null, ParseError.UNEXPECTED_TOKEN.withToken(t));
             }
+            // update type based on Result
             if (typeResult != null && typeResult.isError()) {
                 return new Result<>(typeResult);
             }
             type = typeResult != null ? typeResult.unwrap() : type;
+            // after fully processing one token / a type in parenthesis,
+            // some type should have been parsed
             if (type == null) {
                 return new Result<>(null, ParseError.TOO_FEW_TOKENS);
             }
             if (parenCount - removedParens < 0) {
+                // too many closing parenthesis
                 return new Result<>(null, ParseError.UNEXPECTED_TOKEN.withToken(t));
             } else if (END_TOKENS.contains(t.getType())) {
+                // potential end of type
                 if (parenCount - removedParens == 0) {
+                    // opening and closing parentheses match
                     return new Result<>(new ImmutablePair<>(type, removedParens));
                 } else {
+                    // missing closing parenthesis
                     return new Result<>(null, ParseError.TOO_FEW_TOKENS);
                 }
             }
diff --git a/src/main/java/edu/kit/typicalc/view/main/TypeAssumptionField.java b/src/main/java/edu/kit/typicalc/view/main/TypeAssumptionField.java
index 1f3f597..1428a1d 100644
--- a/src/main/java/edu/kit/typicalc/view/main/TypeAssumptionField.java
+++ b/src/main/java/edu/kit/typicalc/view/main/TypeAssumptionField.java
@@ -48,10 +48,10 @@ public class TypeAssumptionField extends HorizontalLayout implements LocaleChang
     private final transient TypeAssumptionParser parser = new TypeAssumptionParser();
     private final TextField variableInputField;
     private final TextField typeInputField;
-    
+
     private final Binder<String> varBinder = new Binder<>();
     private final Binder<String> typeBinder = new Binder<>();
-    
+
     /**
      * Creates a new TypeAssumptionField with initial values and a callback to remove this
      * type assumption from the {@link TypeAssumptionsArea}.
@@ -87,7 +87,7 @@ public class TypeAssumptionField extends HorizontalLayout implements LocaleChang
         variableInputField.addBlurListener(event -> typeBinder.validate());
         typeInputField.addBlurListener(event -> varBinder.validate());
 
-        addValidatior();
+        addValidator();
         add(variableInputField, typeInputField, deleteButton);
         setId(ASSUMPTIONS_FIELD_ID);
     }
@@ -112,7 +112,7 @@ public class TypeAssumptionField extends HorizontalLayout implements LocaleChang
         return parser.parseType(parseBackType(type)).isOk();
     }
 
-    private void addValidatior() {
+    private void addValidator() {
         varBinder.forField(variableInputField)
                 .withValidator(var -> (hasCorrectVariable(var) || isEmpty()), StringUtils.EMPTY)
                 .bind(o -> variableInputField.getEmptyValue(), null);
@@ -133,10 +133,10 @@ public class TypeAssumptionField extends HorizontalLayout implements LocaleChang
         }
         return new String(rawTypeArray);
     }
-    
+
     /**
      * Checks if both text fields of this type assumption are empty.
-     * 
+     *
      * @return true if both text fields are empty, false if not
      */
     protected boolean isEmpty() {