Small code style fixes + documentation

README.md

@@ -30,8 +30,7 @@ You can now also attach break points in code for debugging purposes, by clicking
 ### Running tests
 To run the unit tests and checkstyle: `mvn test`.
 
-To run the integration tests: `mvn integration-test` (note that due to OS platform differences, it is unlikely that
-you will get a 100% match on the first attempt.)
+To run the integration tests: `mvn integration-test` (note that the screenshots are outdated, so the tests will fail..).
 
 ## Technical documentation
 Documentation on the application is contained in this file and the Javadocs in each source file.

frontend/styles/view/explanation.css

@@ -1,3 +0,0 @@
-#tc-content {
-    overflow-y: auto;
-}

frontend/styles/view/main/error-details.css

@@ -1,3 +0,0 @@
-[part="toggle"] {
-	color: white;
-}

frontend/styles/view/main/info-content.css

@@ -1,4 +0,0 @@
-#inputSyntax {
-    font-family: "Courier", serif;
-    margin-top: 1.5em;
-}

frontend/styles/view/main/syntax-dialog.css

@@ -9,7 +9,7 @@
 	align-items: flex-start;
 }
 
-#input-syntax {
+.input-syntax {
 	font-family: "Courier";
 	margin-top: 1.5em;
 }

src/main/java/edu/kit/typicalc/model/ModelImpl.java

@@ -32,18 +32,18 @@ public class ModelImpl implements Model {
         LambdaParser parser = new LambdaParser(lambdaTerm);
         Result<LambdaTerm, ParseError> result = parser.parse();
         if (result.isError()) {
-            return new Result<>(null, result.unwrapError());
+            return result.castError();
         }
         //Parse Type Assumptions
         TypeAssumptionParser assumptionParser = new TypeAssumptionParser();
         Result<Map<VarTerm, TypeAbstraction>, ParseError> assumptionMap = assumptionParser.parse(typeAssumptions);
         if (assumptionMap.isError()) {
-            return new Result<>(null, assumptionMap.unwrapError());
+            return assumptionMap.castError();
         }
         // scope variables
         LambdaTerm term = result.unwrap();
         term.accept(new ScopingVisitor());
         TypeInferer typeInferer = new TypeInferer(term, assumptionMap.unwrap());
-        return new Result<>(typeInferer, null);
+        return new Result<>(typeInferer);
     }
 }

src/main/java/edu/kit/typicalc/model/Unification.java

@@ -33,8 +33,8 @@ public class Unification {
             Type b = c.getSecondType();
             Result<UnificationActions, UnificationError> actions = a.constrainEqualTo(b);
             if (actions.isError()) {
-                steps.add(new UnificationStep(new Result<>(actions), new ArrayList<>(constraints), Optional.of(c)));
-                substitutionsResult = new Result<>(actions);
+                steps.add(new UnificationStep(actions.castError(), new ArrayList<>(constraints), Optional.of(c)));
+                substitutionsResult = actions.castError();
                 return;
             }
             UnificationActions thisStep = actions.unwrap();

src/main/java/edu/kit/typicalc/model/parser/LambdaLexer.java

@@ -35,7 +35,7 @@ public class LambdaLexer {
         while (true) {
             Result<Token, ParseError> token = parseNextToken();
             if (token.isError()) {
-                result = new Result<>(null, token.unwrapError());
+                result = token.castError();
                 return;
             }
             Token value = token.unwrap();

src/main/java/edu/kit/typicalc/model/parser/LambdaParser.java

@@ -158,7 +158,7 @@ public class LambdaParser {
         }
         Result<VarTerm, ParseError> varTerm = parseVar();
         if (varTerm.isError()) {
-            return new Result<>(varTerm);
+            return varTerm.castError();
         }
         error = expect(TokenType.EQUALS);
         if (error.isPresent()) {
@@ -166,7 +166,7 @@ public class LambdaParser {
         }
         Result<LambdaTerm, ParseError> def = parseTerm(false);
         if (def.isError()) {
-            return new Result<>(def);
+            return def.castError();
         }
         error = expect(TokenType.IN);
         if (error.isPresent()) {
@@ -174,7 +174,7 @@ public class LambdaParser {
         }
         Result<LambdaTerm, ParseError> body = parseTerm(false);
         if (body.isError()) {
-            return new Result<>(body);
+            return body.castError();
         }
         return new Result<>(new LetTerm(varTerm.unwrap(), def.unwrap(), body.unwrap()));
     }
@@ -190,9 +190,9 @@ public class LambdaParser {
                 Result<VarTerm, ParseError> varTerm = parseVar();
                 return new Result<>(varTerm.unwrap()); // variable token can always be parsed
             case LAMBDA:
-                return new Result<>(parseAbstraction());
+                return parseAbstraction().castError();
             case LET:
-                return new Result<>(parseLet());
+                return parseLet().castError();
             case TRUE:
             case FALSE:
                 String boolText = token.getText();

src/main/java/edu/kit/typicalc/util/Result.java

@@ -23,17 +23,6 @@ public class Result<T, E> {
         this.error = null;
     }
 
-    /**
-     * Creates a new result by copying another one.
-     *
-     * @param other the result
-     */
-    @SuppressWarnings("unchecked")
-    public Result(Result<?, ?> other) {
-        this.value = (T) other.value;
-        this.error = (E) other.error;
-    }
-
     /**
      * Creates a new result containing the given value or error.
      * Only one of the parameters may be non-null.
@@ -78,19 +67,6 @@ public class Result<T, E> {
         return value;
     }
 
-    /**
-     * If the result contains a regular value, returns that value.
-     * Otherwise return the supplied alternative value.
-     *
-     * @return the value or the alternative
-     */
-    public T unwrapOr(T alternative) {
-        if (value == null) {
-            return alternative;
-        }
-        return value;
-    }
-
     /**
      * If the result contains an error, returns that error.
      * Otherwise an IllegalStateException is thrown.
@@ -123,8 +99,9 @@ public class Result<T, E> {
      * @param <U> the desired type
      * @return a copy of this object
      */
+    @SuppressWarnings("unchecked")
     public <U> Result<U, E> castError() {
-        return new Result<>(null, this.error);
+        return new Result<>((U) this.value, this.error);
     }
 
     @Override

src/main/java/edu/kit/typicalc/view/OVERVIEW.md

@@ -39,4 +39,14 @@ If a step label is targeted, a tooltip is rendered next to it (was very annoying
 The last paragraph requires that some elements of the proof tree / unification steps are marked using HTML classes
 and CSS IDs. It would be useless to expose this implementation detail to end users (especially since the relevant
 LaTeX macros are unlikely to be defined in the user's environment).
-Note that the actual content is the same for both "modes".
+Note that the actual content is the same for both "modes".
+
+### Special character (∀, λ) input
+
+This is handled by a script (`input-bar-enhancements.ts`) in the user's browser, to reduce latency.
+The buttons next to the input fields are also handled the same way.
+
+### Browser history
+
+Each click on the 'type' button results in a new history entry. Care has been taken that using the back/next buttons
+in the browser actually works (see `UI.navigate` in `MainViewImpl.processInput`).

src/main/java/edu/kit/typicalc/view/content/errorcontent/ErrorView.java

@@ -14,7 +14,7 @@ import edu.kit.typicalc.model.parser.AdditionalInformation;
 import edu.kit.typicalc.model.parser.ExpectedInput;
 import edu.kit.typicalc.model.parser.ParseError;
 import edu.kit.typicalc.model.parser.Token;
-import edu.kit.typicalc.view.main.InfoContent;
+import edu.kit.typicalc.view.main.SyntaxContent;
 
 import java.util.Collection;
 import java.util.Optional;
@@ -41,11 +41,11 @@ public class ErrorView extends VerticalLayout implements LocaleChangeObserver {
         errorMessage = new Div();
         container.add(heading, errorMessage);
 
-        InfoContent infoContent = new InfoContent();
+        SyntaxContent syntaxContent = new SyntaxContent();
         hint = new Paragraph();
-        infoContent.addComponentAsFirst(hint);
+        syntaxContent.addComponentAsFirst(hint);
 
-        add(container, infoContent);
+        add(container, syntaxContent);
     }
 
     private String errorMessageForToken(Token token) {

src/main/java/edu/kit/typicalc/view/content/typeinferencecontent/MathjaxExplanation.java

@@ -3,7 +3,6 @@ package edu.kit.typicalc.view.content.typeinferencecontent;
 import com.vaadin.flow.component.ClientCallable;
 import com.vaadin.flow.component.Html;
 import com.vaadin.flow.component.Tag;
-import com.vaadin.flow.component.dependency.CssImport;
 import com.vaadin.flow.component.dependency.JsModule;
 import com.vaadin.flow.component.html.Div;
 import com.vaadin.flow.component.littemplate.LitTemplate;
@@ -11,17 +10,17 @@ import com.vaadin.flow.component.template.Id;
 import edu.kit.typicalc.view.MathjaxAdapter;
 
 import java.util.List;
+import java.util.function.Consumer;
 
 /**
  * Renders the constraints and unification (LaTeX, using MathJax) and allows step-by-
- * step revealing. Relies on MathjaxUnificationTS to interact with MathJax.
+ * step revealing.
  */
 @Tag("tc-explanation")
 @JsModule("./src/mathjax-explanation.ts")
-@CssImport("./styles/view/explanation.css")
 public class MathjaxExplanation extends LitTemplate implements MathjaxAdapter {
 
-    private final TypeInferenceView typeInferenceView;
+    private final transient Consumer<Integer> stepSwitchCallback;
     private final List<String> latex;
 
     // initialized by Vaadin
@@ -31,15 +30,16 @@ public class MathjaxExplanation extends LitTemplate implements MathjaxAdapter {
     /**
      * Creates a new HTML element that renders the provided texts.
      *
-     * @param view the type inference view this explanation text is attached to
+     * @param stepSwitchCallback the callback used when the user clicks on one of the texts
      * @param latex the latex texts for all steps
      * @param initialStep the step to show initially
      */
-    public MathjaxExplanation(TypeInferenceView view, List<String> latex, int initialStep) {
-        this.typeInferenceView = view;
+    public MathjaxExplanation(Consumer<Integer> stepSwitchCallback, List<String> latex, int initialStep) {
+        this.stepSwitchCallback = stepSwitchCallback;
         this.latex = latex;
         StringBuilder finalTex = new StringBuilder("<div>");
         for (int i = 0; i < latex.size(); i++) {
+            // this class/id is used by the frontend script to locate texts
             finalTex.append(String.format("<p class='tc-text' id='tc-text-%d'>", i));
             finalTex.append(latex.get(i));
             finalTex.append("</p>");
@@ -59,9 +59,12 @@ public class MathjaxExplanation extends LitTemplate implements MathjaxAdapter {
         getElement().callJsFunction("showStep", n);
     }
 
+    /**
+     * Called when the user clicks on the explanation text of a specific step.
+     */
     @ClientCallable
     private void switchToStep(int unificationStepIdx) {
-        typeInferenceView.setCurrentStep(unificationStepIdx);
+        stepSwitchCallback.accept(unificationStepIdx);
     }
 }
 

src/main/java/edu/kit/typicalc/view/content/typeinferencecontent/TypeInferenceView.java

@@ -130,7 +130,8 @@ public class TypeInferenceView extends VerticalLayout
         container.setId(CONTENT_ID2);
         unification = new MathjaxUnification(lc.getUnification());
         var explainer = new ExplanationCreator(typeInferer, getLocale());
-        this.explanation = new MathjaxExplanation(this, explainer.getExplanationTexts(), this.currentStep);
+        this.explanation = new MathjaxExplanation(
+                this::setCurrentStep, explainer.getExplanationTexts(), this.currentStep);
 
         if (tree == null) {
             tree = new MathjaxProofTree(lc.getTree(), stepAnnotations);

src/main/java/edu/kit/typicalc/view/content/typeinferencecontent/latexcreator/AssumptionGeneratorUtil.java

@@ -18,7 +18,15 @@ public final class AssumptionGeneratorUtil {
     private AssumptionGeneratorUtil() {
     }
 
-    protected static String typeAssumptionsToLatex(Map<VarTerm, TypeAbstraction> typeAssumptions,
+    /**
+     * Converts some type assumptions into LaTeX code to display them.
+     * Basic structure: name: Type, otherName: OtherType
+     *
+     * @param typeAssumptions the type assumptions
+     * @param mode latex creator mode
+     * @return the latex code
+     */
+    static String typeAssumptionsToLatex(Map<VarTerm, TypeAbstraction> typeAssumptions,
                                                    LatexCreatorMode mode) {
         if (typeAssumptions.isEmpty()) {
             return "";
@@ -37,6 +45,14 @@ public final class AssumptionGeneratorUtil {
         }
     }
 
+    /**
+     * Return the latex code for a given type abstraction, e.g.:
+     * ∀t1. t1 -> t1
+     *
+     * @param abs the type abstraction
+     * @param mode latex creator mode
+     * @return the latex code
+     */
     public static String generateTypeAbstraction(TypeAbstraction abs, LatexCreatorMode mode) {
         StringBuilder abstraction = new StringBuilder();
         if (abs.hasQuantifiedVariables()) {

src/main/java/edu/kit/typicalc/view/content/typeinferencecontent/latexcreator/LatexCreatorConstants.java

@@ -43,8 +43,6 @@ public final class LatexCreatorConstants {
     protected static final char BRACKET_RIGHT = ']';
 
     protected static final String LABEL_ABS = "\\LeftLabel{\\textrm A{\\small BS}}";
-    protected static final String LABEL_ABS_WITH_CLASS =
-            "\\LeftLabel{\\class{typicalc-label typicalc-label-abs}{\\textrm A{\\small BS}}}";
     protected static final String LABEL_APP = "\\LeftLabel{\\textrm A{\\small PP}}";
     protected static final String LABEL_CONST = "\\LeftLabel{\\textrm C{\\small ONST}}";
     protected static final String LABEL_VAR = "\\LeftLabel{\\textrm V{\\small AR}}";
@@ -73,7 +71,6 @@ public final class LatexCreatorConstants {
     protected static final String FOR_ALL = "\\forall";
     protected static final String MONO_TEXT = "\\texttt";
     protected static final String BOLD_TEXT = "\\textbf";
-    protected static final String TEXT = "\\text";
     protected static final String RIGHT_ARROW = "\\rightarrow";
     protected static final String INSTANTIATE_SIGN = "\\succeq";
     protected static final String LATEX_IN = "\\in";
@@ -86,7 +83,7 @@ public final class LatexCreatorConstants {
     protected static final String SPLIT_END = "\\end{split}";
 
     /**
-     * Not actually a LaTeX command, but understood by MathJax.
+     * Not actually a LaTeX command, but understood by MathJax / the browser.
      */
     protected static final String BREAK_ROW = "<br>";
 }

src/main/java/edu/kit/typicalc/view/content/typeinferencecontent/latexcreator/LatexCreatorConstraints.java

@@ -127,6 +127,14 @@ public class LatexCreatorConstraints implements StepVisitor {
         return numberGenerator.getNumbers();
     }
 
+    /**
+     * Returns the latex code to display a single constraint:
+     * type1 = type2
+     *
+     * @param constraint the constraint
+     * @param mode latex creator mode (if MathJax, adds the step index to the constraint)
+     * @return the latex code
+     */
     public static String createSingleConstraint(Constraint constraint, LatexCreatorMode mode) {
         String firstType = new LatexCreatorType(constraint.getFirstType(), mode).getLatex();
         String secondType = new LatexCreatorType(constraint.getSecondType(), mode).getLatex();
@@ -248,19 +256,28 @@ public class LatexCreatorConstraints implements StepVisitor {
         return latex;
     }
 
+    /**
+     * Main method of this class, creates the latex code for each step of the unification.
+     *
+     * @param constraintSets current constraint set (added to the latex)
+     * @return latex code for each step
+     */
     private List<String> generateUnification(String constraintSets) {
         List<String> steps = new ArrayList<>();
 
         List<UnificationStep> unificationSteps = typeInferer.getUnificationSteps()
                 .orElseThrow(IllegalStateException::new);
         // store constraints of previous step to highlight changes
-        String[] previousConstraints = new String[0];
+        List<String> previousConstraints = new ArrayList<>();
+
         for (int stepNum = 0; stepNum < unificationSteps.size(); stepNum++) {
             UnificationStep step = unificationSteps.get(stepNum);
             List<String> constraints2 = new ArrayList<>();
             Result<List<Substitution>, UnificationError> subs = step.getSubstitutions();
             Optional<UnificationError> error = Optional.empty();
             if (subs.isError()) {
+                // display previous step again
+                // and show the error message
                 error = Optional.of(subs.unwrapError());
                 step = unificationSteps.get(unificationSteps.size() - 2);
                 subs = step.getSubstitutions();
@@ -277,32 +294,37 @@ public class LatexCreatorConstraints implements StepVisitor {
             // if new constraints were created in this step, mark them
             boolean markLastTwoConstraints = (stepNum != 0)
                     && unificationSteps.get(stepNum - 1).getConstraints().size() < unificationConstraints.size();
+
+            // render each constraint present in this step
             if (!unificationConstraints.isEmpty()) {
                 latex.append(UNIFY + PAREN_LEFT + LATEX_CURLY_LEFT);
             }
             for (int i = unificationConstraints.size() - 1; i >= 0; i--) {
                 latex.append(AMPERSAND);
                 StringBuilder sb = new StringBuilder();
+                boolean highligthingConstraint = false;
                 if (markError && i == 0) {
                     sb.append(CURLY_LEFT);
                     sb.append(COLOR_RED);
+                    highligthingConstraint = true;
                 } else if (markLastTwoConstraints && (i < 2)) {
                     sb.append(CURLY_LEFT);
                     sb.append(COLOR_HIGHLIGHTED);
+                    highligthingConstraint = true;
                 }
                 sb.append(new LatexCreatorType(unificationConstraints.get(i).getFirstType(), mode).getLatex());
                 sb.append(EQUALS);
                 sb.append(new LatexCreatorType(unificationConstraints.get(i).getSecondType(), mode).getLatex());
-                if ((markError && i == 0) || markLastTwoConstraints && (i < 2)) {
+                if (highligthingConstraint) {
                     sb.append(CURLY_RIGHT);
                 }
                 constraints2.add(sb.toString());
                 int invIdx = unificationConstraints.size() - 1 - i;
                 // if this constraint was modified by the substitution
-                if (invIdx < previousConstraints.length) {
+                if (invIdx < previousConstraints.size()) {
                     // perform the substitution "manually" and color the new type
                     Substitution s = substitutions.get(substitutions.size() - 1);
-                    String original = previousConstraints[invIdx];
+                    String original = previousConstraints.get(invIdx);
                     String originalType = new LatexCreatorType(s.getVariable(), mode).getLatex();
                     if (original.contains(originalType)) {
                         StringBuilder highlightedChange2 = new StringBuilder();
@@ -326,8 +348,9 @@ public class LatexCreatorConstraints implements StepVisitor {
                 constraints2.remove(constraints2.size() - 1);
                 latex.append(LATEX_CURLY_RIGHT + PAREN_RIGHT + LATEX_NEW_LINE);
             }
-            previousConstraints = constraints2.toArray(new String[0]);
+            previousConstraints = constraints2;
 
+            // also render the substitutions
             for (int i = substitutions.size() - 1; i >= 0; i--) {
                 if (!unificationConstraints.isEmpty() || i != substitutions.size() - 1) {
                     latex.append(CIRC);
@@ -343,6 +366,7 @@ public class LatexCreatorConstraints implements StepVisitor {
             latex.delete(latex.length() - LATEX_NEW_LINE.length(), latex.length());
             latex.append(SPLIT_END);
             latex.append(ALIGN_END + MATH_END);
+            // finally, display the error if there is one
             error.ifPresent(unificationError -> latex.append(translationProvider.apply(unificationError)));
             steps.add(latex.toString());
         }

src/main/java/edu/kit/typicalc/view/content/typeinferencecontent/latexcreator/LatexCreatorMode.java

@@ -4,6 +4,13 @@ package edu.kit.typicalc.view.content.typeinferencecontent.latexcreator;
  * Used to switch between different LaTeX generation methods.
  */
 public enum LatexCreatorMode {
+    /**
+     * This mode adds a few HTML classes and ids to the generated LaTeX to facilitate highlighting etc.
+     * See OVERVIEW.md in the view package for more details.
+     */
     MATHJAX,
+    /**
+     * Regular LaTeX mode. Doesn't use any MathJax extensions.
+     */
     NORMAL
 }

src/main/java/edu/kit/typicalc/view/content/typeinferencecontent/latexcreator/LatexCreatorType.java

@@ -15,7 +15,6 @@ import static edu.kit.typicalc.view.content.typeinferencecontent.latexcreator.La
  * @see Type
  */
 public class LatexCreatorType implements TypeVisitor {
-    private final Type type;
     private static final int MAX_LENGTH = 100000; // 100 KB
     private final LatexCreatorMode mode;
 
@@ -28,7 +27,6 @@ public class LatexCreatorType implements TypeVisitor {
      * @param type the type
      */
     public LatexCreatorType(Type type, LatexCreatorMode mode) {
-        this.type = type;
         this.mode = mode;
         type.accept(this);
     }

src/main/java/edu/kit/typicalc/view/content/typeinferencecontent/latexcreator/TreeNumberGenerator.java

@@ -20,7 +20,7 @@ public class TreeNumberGenerator {
     }
 
     /**
-     * Push the current index. Translates into the tree not doing anything in this step.
+     * Push the current index. This means that the tree will not change in this step.
      */
     protected void push() {
         if (current < 0) {
@@ -30,7 +30,7 @@ public class TreeNumberGenerator {
     }
 
     /**
-     * Push an incremented index. Translates into the tree going to the next step.
+     * Push an incremented index. This advances the proof tree.
      */
     protected void incrementPush() {
         current++;

src/main/java/edu/kit/typicalc/view/main/InputBar.java

@@ -139,7 +139,7 @@ public class InputBar extends HorizontalLayout implements LocaleChangeObserver {
     }
 
     private void onInfoIconClick() {
-        Dialog infoDialog = new InfoDialog();
+        Dialog infoDialog = new SyntaxDialog();
         infoDialog.open();
     }
 

src/main/java/edu/kit/typicalc/view/main/SyntaxContent.java

@@ -9,10 +9,10 @@ import com.vaadin.flow.i18n.LocaleChangeObserver;
 /**
  * Component which contains information on the correct syntax of the term as well as the type assumptions.
  */
-public class InfoContent extends VerticalLayout implements LocaleChangeObserver {
+public class SyntaxContent extends VerticalLayout implements LocaleChangeObserver {
     private static final long serialVersionUID = 7193916603756938225L;
 
-    private static final String GRAMMAR_ID = "input-syntax";
+    private static final String GRAMMAR_CLASS = "input-syntax";
 
     private final Span termExplanation;
     private final Paragraph termSyntax;
@@ -21,16 +21,16 @@ public class InfoContent extends VerticalLayout implements LocaleChangeObserver
     private final Paragraph typeSyntax;
 
     /**
-     * Creates a new InfoContent.
+     * Creates a new SyntaxContent.
      */
-    public InfoContent() {
+    public SyntaxContent() {
         termExplanation = new Span();
         termSyntax = new Paragraph();
         assExplanation = new Span();
         typeExplanation = new Span();
         typeSyntax = new Paragraph();
-        termSyntax.setId(GRAMMAR_ID);
-        typeSyntax.setId(GRAMMAR_ID);
+        termSyntax.setClassName(GRAMMAR_CLASS);
+        typeSyntax.setClassName(GRAMMAR_CLASS);
         add(termExplanation, termSyntax, assExplanation, typeExplanation, typeSyntax);
     }
 

src/main/java/edu/kit/typicalc/view/main/SyntaxDialog.java

@@ -11,8 +11,8 @@ import com.vaadin.flow.component.orderedlayout.VerticalLayout;
 /**
  * Dialog which contains information on the correct syntax for the users input.
  */
-@CssImport("./styles/view/main/info-dialog.css")
-public class InfoDialog extends Dialog {
+@CssImport("./styles/view/main/syntax-dialog.css")
+public class SyntaxDialog extends Dialog {
     private static final long serialVersionUID = 2914411566361539614L;
 
     /*
@@ -23,9 +23,9 @@ public class InfoDialog extends Dialog {
     private static final String CLOSE_ICON_CLASS = "close-icon";
 
     /**
-     * Creates new InfoDialog.
+     * Creates new SyntaxDialog.
      */
-    protected InfoDialog() {
+    protected SyntaxDialog() {
         H4 heading = new H4(getTranslation("root.inputSyntax"));
         HorizontalLayout infoHeader = new HorizontalLayout(heading);
         Icon closeIcon = new Icon(VaadinIcon.CLOSE_SMALL);
@@ -34,7 +34,7 @@ public class InfoDialog extends Dialog {
         infoHeader.setId(INFO_HEADER_ID);
         infoHeader.add(closeIcon);
 
-        VerticalLayout infoContent = new InfoContent();
+        VerticalLayout infoContent = new SyntaxContent();
         infoContent.setId(INFO_CONTENT_ID);
 
         add(infoHeader, infoContent);

src/main/java/edu/kit/typicalc/view/main/TermExampleContent.java

@@ -8,7 +8,7 @@ import com.vaadin.flow.component.orderedlayout.VerticalLayout;
 
 /**
  * Contains all predefined examples as buttons.
- * Clicking on a button selects the example and allows the user to chose between various type assumptions.
+ * Clicking on a button selects the example and allows the user to choose between various type assumptions.
  */
 public class TermExampleContent extends VerticalLayout {
     private static final long serialVersionUID = 2882744650931562239L;

src/main/resources/language/translation_de.properties

@@ -75,7 +75,8 @@ root.helpShortcuts=<kbd>Strg</kbd> + <kbd>\u2190</kbd> = Erster Schritt<br>\
 root.helpHoverEffects=Durch das Hovern über den Typherleitungsbaum und die Unifikation können zusätzliche Informationen \
 angezeigt werden. Das Hovern über eine beliebige Variable im Typherleitungsbaum oder der Unifikation führt dazu, dass \
 alle Vorkommen dieser Variable farblich hervorgehoben werden. Beim Hovern über die Schrift einer beliebigen Regel im \
-Typherleitungsbaum wird die Regel allgemein und die Instanziierung aller vorkommenden Variablen angezeigt.
+Typherleitungsbaum wird die Regel allgemein und die Instanziierung aller vorkommenden Variablen angezeigt. \
+Außerdem wird der von diesem Schritt erzeugte Constraint hervorgehoben.
 root.helpFirstStepButton=Je nach Stand der Algorithmusausführung ändert sich die Funktion des Knopfs. \
 Wenn aktuell der Baum aufgebaut wird, springt die Anzeige nach Benutzen des Knopfs zurück zum ersten Schritt des \
 Typherleitungsbaums. Wenn bereits die Unifikation durchgeführt wird, springt die Anzeige nach Benutzen des Knopfs \

src/main/resources/language/translation_en.properties

@@ -72,7 +72,7 @@ root.helpShortcuts=<kbd>Ctrl</kbd> + <kbd>\u2190</kbd> = First step<br>\
 root.helpHoverEffects=Additional information can be displayed by hovering over the inference tree and the unification. \
 Hovering over an arbitrary variable in the tree or the unification highlights all occurences of this variable. Hovering \
 over the label of an inference rule in the tree displays the general scheme of the rule as well as the instantiation of \
-all occuring variables.
+all occuring variables. Additionally the constraint added in that step is highlighted in the unification area above.
 root.helpFirstStepButton=The function of the button depends on the current state of the algorithm. \
 If the tree is currently being built up, clicking on the button shows the first step of the inference tree. \
 If the unification algorithm is already in progress, clicking on the button shows the last step of the inference \

src/test/java/edu/kit/typicalc/model/parser/LambdaParserTest.java

@@ -65,10 +65,6 @@ class LambdaParserTest {
     void complicatedTerm() {
         LambdaParser parser = new LambdaParser("(λx.λy.x y 5)(λz.z)(true)");
         Result<LambdaTerm, ParseError> term = parser.parse();
-        if (term.isError()) {
-            System.err.println(term.unwrapError());
-            System.err.println(term.unwrapError().getCause());
-        }
         assertEquals(
                 new AppTerm(
                         new AppTerm(