[2097] Handle expressions in SysON

Bug: #2097
Signed-off-by: Pierre-Charles David <pierre-charles.david@obeo.fr>

Author: pcdavid

CHANGELOG.adoc

@@ -40,6 +40,8 @@ Disabling the _Hide expression internals_ filter in the _Explorer_ view allows t
 - https://github.com/eclipse-syson/syson/issues/2235[#2235] [diagrams] Leverage the selection dialog to improve the graphical node tool creating a _frame_ `ConcernUsage` from `RequirementUsage` and `RequirementDefinition` graphical nodes.
 - https://github.com/eclipse-syson/syson/issues/2242[#2242] [explorer] Add two options to the dialog creating a child element of `RequirementUsage` or `RequirementDefinition` tree items.
 One creates a `ConcernUsage` and another one creates `FramedConcernMembership`.
+- https://github.com/eclipse-syson/syson/issues/2097[#2097] [explorer] Add support for creating and editing exressions through their textual representation.
+This is currently supported on `Features` (e.g. `Attribute`), `Constraints` and `Transitions` (guard conditions) view new context menu actions (_Create expression_ and _Edit expression_) on the corresponding elements in the _Explorer_.
 
 == v2026.5.0
 

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/configuration/SysMLv2PropertiesConfigurer.java

@@ -25,7 +25,6 @@
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.emf.ecore.xmi.impl.XMIResourceImpl;
-import org.eclipse.syson.sysml.Element;
 import org.eclipse.emf.edit.provider.ComposedAdapterFactory.Descriptor;
 import org.eclipse.sirius.components.collaborative.forms.services.api.IPropertiesDescriptionRegistry;
 import org.eclipse.sirius.components.collaborative.forms.services.api.IPropertiesDescriptionRegistryConfigurer;
@@ -63,8 +62,9 @@
 import org.eclipse.syson.model.services.ModelMutationElementService;
 import org.eclipse.syson.model.services.aql.ModelMutationAQLService;
 import org.eclipse.syson.model.services.aql.ModelQueryAQLService;
-import org.eclipse.syson.services.UtilService;
+import org.eclipse.syson.sysml.Element;
 import org.eclipse.syson.sysml.SysmlPackage;
+import org.eclipse.syson.sysml.metamodel.services.MetamodelQueryElementService;
 import org.eclipse.syson.util.AQLConstants;
 import org.eclipse.syson.util.AQLUtils;
 import org.eclipse.syson.util.ServiceMethod;
@@ -119,10 +119,10 @@ public class SysMLv2PropertiesConfigurer implements IPropertiesDescriptionRegist
 
     private final ILabelService labelService;
 
-    private final UtilService utilService;
-
     private final IReadOnlyObjectPredicate readOnlyObjectPredicate;
 
+    private final MetamodelQueryElementService metamodelQueryElementService;
+
     private final List<IDetailsViewHelpTextProvider> detailViewHelpTextProviders;
 
     public SysMLv2PropertiesConfigurer(List<Descriptor> composedAdapterFactoryDescriptors, ViewFormDescriptionConverter converter, IFeedbackMessageService feedbackMessageService,
@@ -133,7 +133,7 @@ public SysMLv2PropertiesConfigurer(List<Descriptor> composedAdapterFactoryDescri
         this.labelService = Objects.requireNonNull(labelService);
         this.readOnlyObjectPredicate = Objects.requireNonNull(readOnlyObjectPredicate);
         this.detailViewHelpTextProviders = Objects.requireNonNull(detailViewHelpTextProviders);
-        this.utilService = new UtilService();
+        this.metamodelQueryElementService = new MetamodelQueryElementService();
     }
 
     @Override
@@ -155,7 +155,8 @@ public void addPropertiesDescriptions(IPropertiesDescriptionRegistry registry) {
 
         // Convert the View-based FormDescription and register the result into the system
         AQLInterpreter interpreter = new AQLInterpreter(List.of(),
-                List.of(new DetailsViewService(this.composedAdapterFactoryDescriptors, this.feedbackMessageService, this.readOnlyObjectPredicate, this.detailViewHelpTextProviders), this.labelService, this.utilService,
+                List.of(new DetailsViewService(this.composedAdapterFactoryDescriptors, this.feedbackMessageService, this.readOnlyObjectPredicate, this.metamodelQueryElementService,
+                        this.detailViewHelpTextProviders), this.labelService,
                         new ModelMutationAQLService(new ModelMutationElementService()), new ModelQueryAQLService(), new FormMutationAQLService(), new FormQueryAQLService()),
                 List.of(SysmlPackage.eINSTANCE));
         ViewConverterResult converterResult = this.converter.convert(viewFormDescription, List.of(), interpreter);

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/expressions/dto/DeleteExpressionInput.java

@@ -0,0 +1,25 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Obeo.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.application.expressions.dto;
+
+import java.util.UUID;
+
+import org.eclipse.sirius.components.core.api.IInput;
+
+/**
+ * The input object for the {@code deleteExpression} mutation.
+ *
+ * @author pcdavid
+ */
+public record DeleteExpressionInput(UUID id, String editingContextId, String parentElementId) implements IInput {
+}

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/expressions/dto/ExpressionTextualRepresentationInput.java

@@ -0,0 +1,25 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Obeo.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.application.expressions.dto;
+
+import java.util.UUID;
+
+import org.eclipse.sirius.components.core.api.IInput;
+
+/**
+ * Input for the {@code expressionTextualRepresentation} query field on EditingContext.
+ *
+ * @author pcdavid
+ */
+public record ExpressionTextualRepresentationInput(UUID id, String editingContextId, String elementId) implements IInput {
+}

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/expressions/dto/ExpressionTextualRepresentationPayload.java

@@ -0,0 +1,29 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Obeo.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.application.expressions.dto;
+
+import java.util.Objects;
+import java.util.UUID;
+
+import org.eclipse.sirius.components.core.api.IPayload;
+
+/**
+ * Payload for the {@code expressionTextualRepresentation} query field on EditingContext.
+ *
+ * @author pcdavid
+ */
+public record ExpressionTextualRepresentationPayload(UUID id, String textualRepresentation) implements IPayload {
+    public ExpressionTextualRepresentationPayload {
+        Objects.requireNonNull(id);
+    }
+}

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/expressions/graphql/EditingContextExpressionTextualRepresentationDataFetcher.java

@@ -0,0 +1,56 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Obeo.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.application.expressions.graphql;
+
+import java.util.Objects;
+import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
+
+import org.eclipse.sirius.components.annotations.spring.graphql.QueryDataFetcher;
+import org.eclipse.sirius.components.graphql.api.IDataFetcherWithFieldCoordinates;
+import org.eclipse.sirius.components.graphql.api.IEditingContextDispatcher;
+import org.eclipse.syson.application.expressions.dto.ExpressionTextualRepresentationInput;
+import org.eclipse.syson.application.expressions.dto.ExpressionTextualRepresentationPayload;
+
+import graphql.schema.DataFetchingEnvironment;
+
+/**
+ * Data fetcher for the field {@code EditingContext#expressionTextualRepresentation} to fetch the textual representation
+ * of a SysMLv2 expression.
+ *
+ * @author pcdavid
+ */
+@QueryDataFetcher(type = "EditingContext", field = "expressionTextualRepresentation")
+public class EditingContextExpressionTextualRepresentationDataFetcher implements IDataFetcherWithFieldCoordinates<CompletableFuture<String>> {
+
+    private static final String ELEMENT_ID_ARGUMENT = "elementId";
+
+    private final IEditingContextDispatcher editingContextDispatcher;
+
+    public EditingContextExpressionTextualRepresentationDataFetcher(IEditingContextDispatcher editingContextDispatcher) {
+        this.editingContextDispatcher = Objects.requireNonNull(editingContextDispatcher);
+    }
+
+    @Override
+    public CompletableFuture<String> get(DataFetchingEnvironment environment) throws Exception {
+        String editingContextId = environment.getSource();
+        String elementId = environment.getArgument(ELEMENT_ID_ARGUMENT);
+
+        ExpressionTextualRepresentationInput input = new ExpressionTextualRepresentationInput(UUID.randomUUID(), editingContextId, elementId);
+        return this.editingContextDispatcher.dispatchQuery(input.editingContextId(), input)
+                .filter(ExpressionTextualRepresentationPayload.class::isInstance)
+                .map(ExpressionTextualRepresentationPayload.class::cast)
+                .map(ExpressionTextualRepresentationPayload::textualRepresentation)
+                .toFuture();
+    }
+}

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/expressions/graphql/MutationDeleteExpressionDataFetcher.java

@@ -0,0 +1,57 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Obeo.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.application.expressions.graphql;
+
+import java.util.Objects;
+import java.util.concurrent.CompletableFuture;
+
+import org.eclipse.sirius.components.annotations.spring.graphql.MutationDataFetcher;
+import org.eclipse.sirius.components.core.api.IPayload;
+import org.eclipse.sirius.components.graphql.api.IDataFetcherWithFieldCoordinates;
+import org.eclipse.sirius.components.graphql.api.IEditingContextDispatcher;
+import org.eclipse.sirius.components.graphql.api.IExceptionWrapper;
+import org.eclipse.syson.application.expressions.dto.DeleteExpressionInput;
+
+import graphql.schema.DataFetchingEnvironment;
+import tools.jackson.databind.ObjectMapper;
+
+/**
+ * The GraphQL data-fetcher for the {@code deleteExpression} mutation to delete the expression associated to a SysMLv2
+ * element.
+ *
+ * @author pcdavid
+ */
+@MutationDataFetcher(type = "Mutation", field = "deleteExpression")
+public class MutationDeleteExpressionDataFetcher implements IDataFetcherWithFieldCoordinates<CompletableFuture<IPayload>> {
+
+    private static final String INPUT_ARGUMENT = "input";
+
+    private final ObjectMapper objectMapper;
+
+    private final IExceptionWrapper exceptionWrapper;
+
+    private final IEditingContextDispatcher editingContextDispatcher;
+
+    public MutationDeleteExpressionDataFetcher(ObjectMapper objectMapper, IExceptionWrapper exceptionWrapper, IEditingContextDispatcher editingContextDispatcher) {
+        this.objectMapper = Objects.requireNonNull(objectMapper);
+        this.exceptionWrapper = Objects.requireNonNull(exceptionWrapper);
+        this.editingContextDispatcher = Objects.requireNonNull(editingContextDispatcher);
+    }
+
+    @Override
+    public CompletableFuture<IPayload> get(DataFetchingEnvironment environment) throws Exception {
+        Object argument = environment.getArgument(INPUT_ARGUMENT);
+        var input = this.objectMapper.convertValue(argument, DeleteExpressionInput.class);
+        return this.exceptionWrapper.wrapMono(() -> this.editingContextDispatcher.dispatchMutation(input.editingContextId(), input), input).toFuture();
+    }
+}

backend/application/syson-application-configuration/src/main/java/org/eclipse/syson/application/expressions/services/DeleteExpressionEventHandler.java

@@ -0,0 +1,86 @@
+/*******************************************************************************
+ * Copyright (c) 2026 Obeo.
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Obeo - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.syson.application.expressions.services;
+
+import java.util.Objects;
+import java.util.Optional;
+
+import org.eclipse.sirius.components.collaborative.api.ChangeDescription;
+import org.eclipse.sirius.components.collaborative.api.ChangeKind;
+import org.eclipse.sirius.components.collaborative.api.IEditingContextEventHandler;
+import org.eclipse.sirius.components.collaborative.messages.ICollaborativeMessageService;
+import org.eclipse.sirius.components.core.api.ErrorPayload;
+import org.eclipse.sirius.components.core.api.IEditingContext;
+import org.eclipse.sirius.components.core.api.IInput;
+import org.eclipse.sirius.components.core.api.IObjectSearchService;
+import org.eclipse.sirius.components.core.api.IPayload;
+import org.eclipse.sirius.components.core.api.SuccessPayload;
+import org.eclipse.syson.application.expressions.dto.DeleteExpressionInput;
+import org.eclipse.syson.services.DeleteService;
+import org.eclipse.syson.sysml.Element;
+import org.eclipse.syson.sysml.Expression;
+import org.eclipse.syson.sysml.metamodel.services.MetamodelQueryElementService;
+import org.springframework.stereotype.Service;
+
+import reactor.core.publisher.Sinks;
+
+/**
+ * Event handler for the {@code deleteExpression} mutation.
+ *
+ * @author pcdavid
+ */
+@Service
+public class DeleteExpressionEventHandler implements IEditingContextEventHandler {
+
+    private final IObjectSearchService objectSearchService;
+
+    private final MetamodelQueryElementService metamodelQueryElementService;
+
+    private final ICollaborativeMessageService messageService;
+
+    private final DeleteService deleteService;
+
+    public DeleteExpressionEventHandler(IObjectSearchService objectSearchService, ICollaborativeMessageService messageService) {
+        this.objectSearchService = Objects.requireNonNull(objectSearchService);
+        this.metamodelQueryElementService = new MetamodelQueryElementService();
+        this.messageService = Objects.requireNonNull(messageService);
+        this.deleteService = new DeleteService();
+    }
+
+    @Override
+    public boolean canHandle(IEditingContext editingContext, IInput input) {
+        return input instanceof DeleteExpressionInput;
+    }
+
+    @Override
+    public void handle(Sinks.One<IPayload> payloadSink, Sinks.Many<ChangeDescription> changeDescriptionSink, IEditingContext editingContext, IInput input) {
+        IPayload payload;
+        if (input instanceof DeleteExpressionInput deleteExpressionInput) {
+            Optional<Expression> optionalExpression = this.objectSearchService.getObject(editingContext, deleteExpressionInput.parentElementId())
+                    .filter(Element.class::isInstance)
+                    .map(Element.class::cast)
+                    .flatMap(element -> this.metamodelQueryElementService.findSingleExpressionDefinition(element));
+            if (optionalExpression.isPresent()) {
+                this.deleteService.deleteFromModel(optionalExpression.get());
+                var changeDescription = new ChangeDescription(ChangeKind.SEMANTIC_CHANGE, editingContext.getId(), input);
+                changeDescriptionSink.tryEmitNext(changeDescription);
+                payload = new SuccessPayload(input.id());
+            } else {
+                payload = new ErrorPayload(input.id(), this.messageService.notFound());
+            }
+        } else {
+            payload = new ErrorPayload(input.id(), this.messageService.invalidInput(DeleteExpressionInput.class.getName(), input.getClass().getName()));
+        }
+        payloadSink.tryEmitValue(payload);
+    }
+}