CATROID-909: Enable evaluation of user-defined functions in formulas

catroid/build.gradle

@@ -227,7 +227,7 @@ android {
         release {
             buildConfigField "boolean", "FEATURE_MERGE_ENABLED", "false"
             buildConfigField "boolean", "FEATURE_POCKETMUSIC_ENABLED", "false"
-            buildConfigField "boolean", "FEATURE_USER_REPORTERS_ENABLED", "false"
+            buildConfigField "boolean", "FEATURE_USER_REPORTERS_ENABLED", "true"
             resValue "string", "SNACKBAR_HINTS_ENABLED", "true"
             signingConfig signingConfigs.debug
         }

catroid/src/main/java/org/catrobat/catroid/content/ActionFactory.java

@@ -1488,13 +1488,14 @@ public Action createStopScriptAction(int spinnerSelection, Script currentScript,
 		}
 	}
 
-	public Action createReportAction(Sprite sprite, SequenceAction sequence, Script currentScript, Formula reportFormula) {
+	public Action createReportAction(Sprite sprite, ScriptSequenceAction sequence, Script currentScript, Formula reportFormula) {
 		if (currentScript instanceof UserDefinedScript) {
 			ReportAction reportAction = Actions.action(ReportAction.class);
 			Scope scope = new Scope(ProjectManager.getInstance().getCurrentProject(), sprite, sequence);
 			reportAction.setScope(scope);
 			reportAction.setCurrentScript(currentScript);
 			reportAction.setReportFormula(reportFormula);
+			reportAction.setCallId(sequence.callId);
 			return reportAction;
 		} else {
 			StopThisScriptAction stopThisScriptAction = Actions.action(StopThisScriptAction.class);

catroid/src/main/java/org/catrobat/catroid/content/EventWrapperListener.kt

@@ -60,6 +60,7 @@ class EventWrapperListener internal constructor(private val look: Look) : EventL
             scriptClone.setUserDefinedBrickInputs((event.eventId as
                 UserDefinedBrickEventId).userBrickParameters)
             val sequenceClone: ScriptSequenceAction = sequenceAction.cloneAndChangeScript(scriptClone)
+            sequenceClone.callId = (event.eventId as UserDefinedBrickEventId).callId
             sequenceClone.script.run(sprite, sequenceClone)
             event.addSpriteToWaitList(sprite)
             startThread(ScriptSequenceActionWithWaiter(sequenceClone, event, sprite))

catroid/src/main/java/org/catrobat/catroid/content/actions/ReportAction.java

@@ -35,6 +35,7 @@
 	private Script currentScript;
 	private Formula reportFormula;
 	private Scope scope;
+	private long callId = -1;
 
 	public void setScope(Scope scope) {
 		this.scope = scope;
@@ -48,6 +49,10 @@
 		this.reportFormula = reportFormula;
 	}
 
+	public void setCallId(long callId) {
+		this.callId = callId;
+	}
+
 	public Formula getReportFormula() {
 		return this.reportFormula;
 	}
@@ -58,8 +63,12 @@
 
 	@Override
 	public boolean act(float delta) {
-		if (actor instanceof Look) {
-			((Look) actor).stopThreadWithScript(currentScript);
+		if (callId != -1) {
+			Object value = reportFormula.interpretObject(scope);
+			org.catrobat.catroid.formulaeditor.FunctionCallManager.getInstance().setResult(callId, value);
+		}
+		if (actor instanceof org.catrobat.catroid.content.Look) {
+			((org.catrobat.catroid.content.Look) actor).stopThreadWithScript(currentScript);
 		}
 		return true;
 	}

catroid/src/main/java/org/catrobat/catroid/content/actions/ScriptSequenceAction.java

@@ -33,6 +33,7 @@
 
 public class ScriptSequenceAction extends SequenceAction {
 	protected final Script script;
+	public long callId = -1;
 
 	public ScriptSequenceAction(@NonNull Script script) {
 		this.script = script;

catroid/src/main/java/org/catrobat/catroid/content/bricks/ReportBrick.java

@@ -44,7 +44,7 @@ public int getViewResource() {
 	@Override
 	public void addActionToSequence(Sprite sprite, ScriptSequenceAction sequence) {
 		sequence.addAction(sprite.getActionFactory()
-				.createReportAction(sprite, new SequenceAction(), sequence.getScript(),
+				.createReportAction(sprite, sequence, sequence.getScript(),
 						getFormulaWithBrickField(BrickField.REPORT_BRICK)));
 	}
 }

catroid/src/main/java/org/catrobat/catroid/content/eventids/UserDefinedBrickEventId.java

@@ -29,16 +29,22 @@
 public class UserDefinedBrickEventId extends EventId {
 	public final UUID userDefinedBrickID;
 	public List<Object> userBrickParameters;
+	public long callId = -1;
 
 	public UserDefinedBrickEventId(UUID userDefinedBrickID,
-			List<Object> userBrickParameters) {
+			List<Object> userBrickParameters, long callId) {
 		this.userDefinedBrickID = userDefinedBrickID;
 		this.userBrickParameters = userBrickParameters;
+		this.callId = callId;
+	}
+
+	public UserDefinedBrickEventId(UUID userDefinedBrickID,
+			List<Object> userBrickParameters) {
+		this(userDefinedBrickID, userBrickParameters, -1);
 	}
 
 	public UserDefinedBrickEventId(UUID userDefinedBrickID) {
-		this.userDefinedBrickID = userDefinedBrickID;
-		this.userBrickParameters = null;
+		this(userDefinedBrickID, null, -1);
 	}
 
 	@Override

catroid/src/main/java/org/catrobat/catroid/formulaeditor/FormulaElement.java

@@ -23,10 +23,12 @@
 package org.catrobat.catroid.formulaeditor;
 
 import org.catrobat.catroid.ProjectManager;
+import org.catrobat.catroid.content.EventWrapper;
 import org.catrobat.catroid.content.Project;
 import org.catrobat.catroid.content.Scene;
 import org.catrobat.catroid.content.Scope;
 import org.catrobat.catroid.content.bricks.Brick;
+import org.catrobat.catroid.content.eventids.UserDefinedBrickEventId;
 import org.catrobat.catroid.formulaeditor.function.ArduinoFunctionProvider;
 import org.catrobat.catroid.formulaeditor.function.BinaryFunction;
 import org.catrobat.catroid.formulaeditor.function.FormulaFunction;
@@ -55,6 +57,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import java.util.UUID;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -99,7 +102,7 @@ public class FormulaElement implements Serializable {
 	private static final long serialVersionUID = 1L;
 
 	public enum ElementType {
-		OPERATOR, FUNCTION, NUMBER, SENSOR, USER_VARIABLE, USER_LIST, USER_DEFINED_BRICK_INPUT, BRACKET, STRING, COLLISION_FORMULA
+		OPERATOR, FUNCTION, NUMBER, SENSOR, USER_VARIABLE, USER_LIST, USER_DEFINED_BRICK_INPUT, BRACKET, STRING, COLLISION_FORMULA, USER_DEFINED_FUNCTION
 	}
 
 	private ElementType type;
@@ -207,6 +210,9 @@ public List<InternToken> getInternTokenList() {
 			case COLLISION_FORMULA:
 				addToken(tokens, COLLISION_FORMULA, value);
 				break;
+			case USER_DEFINED_FUNCTION:
+				addUserDefinedFunctionTokens(tokens, value, leftChild, rightChild, additionalChildren);
+				break;
 		}
 		return tokens;
 	}
@@ -231,25 +237,32 @@ private void addOperatorTokens(List<InternToken> tokens, String value) {
 		tryAddInternTokens(tokens, rightChild);
 	}
 
+	private void addUserDefinedFunctionTokens(List<InternToken> tokens, String brickId, FormulaElement leftChild,
+			FormulaElement rightChild, List<FormulaElement> additionalChildren) {
+		tokens.add(new InternToken(InternTokenType.USER_DEFINED_FUNCTION, brickId));
+		addParameterTokens(tokens, leftChild, rightChild, additionalChildren);
+	}
+
 	private void addFunctionTokens(List<InternToken> tokens, String value, FormulaElement leftChild, FormulaElement rightChild) {
 		addToken(tokens, FUNCTION_NAME, value);
-		boolean functionHasParameters = false;
+		addParameterTokens(tokens, leftChild, rightChild, additionalChildren);
+	}
+
+	private void addParameterTokens(List<InternToken> tokens, FormulaElement leftChild,
+			FormulaElement rightChild, List<FormulaElement> additionalChildren) {
 		if (leftChild != null) {
 			addToken(tokens, FUNCTION_PARAMETERS_BRACKET_OPEN);
-			functionHasParameters = true;
 			tokens.addAll(leftChild.getInternTokenList());
-		}
-		if (rightChild != null) {
-			addToken(tokens, FUNCTION_PARAMETER_DELIMITER);
-			tokens.addAll(rightChild.getInternTokenList());
-		}
-		for (FormulaElement child : additionalChildren) {
-			if (child != null) {
+			if (rightChild != null) {
 				addToken(tokens, FUNCTION_PARAMETER_DELIMITER);
-				tokens.addAll(child.getInternTokenList());
+				tokens.addAll(rightChild.getInternTokenList());
+			}
+			for (FormulaElement child : additionalChildren) {
+				if (child != null) {
+					addToken(tokens, FUNCTION_PARAMETER_DELIMITER);
+					tokens.addAll(child.getInternTokenList());
+				}
 			}
-		}
-		if (functionHasParameters) {
 			addToken(tokens, FUNCTION_PARAMETERS_BRACKET_CLOSE);
 		}
 	}
@@ -429,6 +442,8 @@ private Object rawInterpretRecursive(Scope scope) {
 				StageListener stageListener = StageActivity.stageListener;
 				return tryInterpretCollision(scope.getSprite().look, value, currentlyPlayingScene,
 						stageListener);
+			case USER_DEFINED_FUNCTION:
+				return interpretUserDefinedFunction(scope);
 		}
 		return FALSE;
 	}
@@ -525,6 +540,31 @@ private Object interpretFormulaFunction(Functions function, List<Object> argumen
 		return formulaFunction.execute(argumentsDouble.get(0), argumentsDouble.get(1), argumentsDouble.get(2));
 	}
 
+
+	private Object interpretUserDefinedFunction(Scope scope) {
+		UUID brickId = UUID.fromString(value);
+
+		List<Object> parameters = new ArrayList<>();
+		if (leftChild != null) {
+			parameters.add(leftChild.interpretRecursive(scope));
+			if (rightChild != null) {
+				parameters.add(rightChild.interpretRecursive(scope));
+				for (FormulaElement child : additionalChildren) {
+					parameters.add(child.interpretRecursive(scope));
+				}
+			}
+		}
+
+		long callId = FunctionCallManager.getInstance().createCall();
+		UserDefinedBrickEventId eventId = new UserDefinedBrickEventId(brickId, parameters, callId);
+
+		if (scope.getSprite() != null) {
+			scope.getSprite().look.fire(new EventWrapper(eventId, false));
+		}
+
+		return FunctionCallManager.getInstance().waitForResult(callId);
+	}
+
 	private Object interpretFunctionNumberOfItems(Object left, Scope scope) {
 		if (leftChild.type == ElementType.USER_LIST) {
 			UserList userList = UserDataWrapper.getUserList(leftChild.value, scope);

catroid/src/main/java/org/catrobat/catroid/formulaeditor/FunctionCallManager.kt

@@ -0,0 +1,81 @@
+/*
+ * Catroid: An on-device visual programming system for Android devices
+ * Copyright (C) 2010-2025 The Catrobat Team
+ * (<http://developer.catrobat.org/credits>)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * An additional term exception under section 7 of the GNU Affero
+ * General Public License, version 3, is available at
+ * http://developer.catrobat.org/license_additional_term
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.catrobat.catroid.formulaeditor
+
+import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.CountDownLatch
+import java.util.concurrent.TimeUnit
+import java.util.concurrent.atomic.AtomicLong
+
+class FunctionCallManager private constructor() {
+
+    private val callIdCounter = AtomicLong(0)
+    private val pendingCalls = ConcurrentHashMap<Long, CallResult>()
+
+    fun createCall(): Long {
+        val id = callIdCounter.incrementAndGet()
+        pendingCalls[id] = CallResult()
+        return id
+    }
+
+    fun waitForResult(callId: Long): Any {
+        val result = pendingCalls[callId] ?: return DEFAULT_VALUE
+
+        return try {
+            if (result.latch.await(TIMEOUT_SECONDS, TimeUnit.SECONDS)) {
+                result.value ?: DEFAULT_VALUE
+            } else {
+                DEFAULT_VALUE
+            }
+        } catch (e: InterruptedException) {
+            Thread.currentThread().interrupt()
+            DEFAULT_VALUE
+        } finally {
+            pendingCalls.remove(callId)
+        }
+    }
+
+    fun setResult(callId: Long, value: Any?) {
+        val result = pendingCalls[callId]
+        if (result != null) {
+            result.value = value
+            result.latch.countDown()
+        }
+    }
+
+    private class CallResult {
+        val latch = CountDownLatch(1)
+
+        @Volatile
+        var value: Any? = null
+    }
+
+    companion object {
+        private const val TIMEOUT_SECONDS = 30L
+        private const val DEFAULT_VALUE = 0.0
+
+        @JvmStatic
+        val instance = FunctionCallManager()
+    }
+}

catroid/src/main/java/org/catrobat/catroid/formulaeditor/InternFormulaParser.java

@@ -251,6 +251,10 @@ private FormulaElement term(Scope scope) throws InternFormulaParserException {
 				currentElement.replaceElement(collision());
 				break;
 
+			case USER_DEFINED_FUNCTION:
+				currentElement.replaceElement(userDefinedFunction(scope));
+				break;
+
 			default:
 				throw new InternFormulaParserException("Parse Error");
 		}
@@ -331,6 +335,20 @@ private FormulaElement function(Scope scope) throws InternFormulaParserException
 		FormulaElement functionTree = new FormulaElement(FormulaElement.ElementType.FUNCTION, currentToken.getTokenStringValue(), null);
 		getNextToken();
 
+		parseParameters(functionTree, scope);
+		return functionTree;
+	}
+
+	private FormulaElement userDefinedFunction(Scope scope) throws InternFormulaParserException {
+		FormulaElement functionTree = new FormulaElement(FormulaElement.ElementType.USER_DEFINED_FUNCTION,
+				currentToken.getTokenStringValue(), null);
+		getNextToken();
+
+		parseParameters(functionTree, scope);
+		return functionTree;
+	}
+
+	private void parseParameters(FormulaElement functionTree, Scope scope) throws InternFormulaParserException {
 		if (currentToken.isFunctionParameterBracketOpen()) {
 			getNextToken();
 			functionTree.setLeftChild(termList(scope));
@@ -347,7 +365,6 @@ private FormulaElement function(Scope scope) throws InternFormulaParserException
 			}
 			getNextToken();
 		}
-		return functionTree;
 	}
 
 	private String number() throws InternFormulaParserException {

catroid/src/main/java/org/catrobat/catroid/formulaeditor/InternToken.java

@@ -132,6 +132,10 @@ public boolean isString() {
 		return internTokenType == InternTokenType.STRING;
 	}
 
+	public boolean isUserDefinedFunction() {
+		return internTokenType == InternTokenType.USER_DEFINED_FUNCTION;
+	}
+
 	public void appendToTokenStringValue(String stringToAppend) {
 		this.tokenStringValue += stringToAppend;
 	}

catroid/src/main/java/org/catrobat/catroid/formulaeditor/InternTokenType.java

@@ -25,5 +25,5 @@
 public enum InternTokenType {
 	NUMBER, OPERATOR, FUNCTION_NAME, BRACKET_OPEN, BRACKET_CLOSE, SENSOR, FUNCTION_PARAMETERS_BRACKET_OPEN,
 	FUNCTION_PARAMETERS_BRACKET_CLOSE, FUNCTION_PARAMETER_DELIMITER, PERIOD, USER_VARIABLE,
-	USER_LIST, USER_DEFINED_BRICK_INPUT, COLLISION_FORMULA, STRING, PARSER_END_OF_FILE,
+	USER_LIST, USER_DEFINED_BRICK_INPUT, COLLISION_FORMULA, STRING, PARSER_END_OF_FILE, USER_DEFINED_FUNCTION,
 }

catroid/src/main/java/org/catrobat/catroid/ui/fragment/CategoryBricksFactory.kt

@@ -447,7 +447,7 @@ open class CategoryBricksFactory {
         var userDefinedBricks: MutableList<Brick> = ArrayList()
         if (currentSprite != null) userDefinedBricks = currentSprite.userDefinedBrickList
         userDefinedBricks = ArrayList(userDefinedBricks)
-        if (BuildConfig.FEATURE_USER_REPORTERS_ENABLED) userDefinedBricks.add(ReportBrick())
+        userDefinedBricks.add(ReportBrick())
         return userDefinedBricks
     }