From 23b0925f419894cf3f4699fa49dd91fb2ee4f4a5 Mon Sep 17 00:00:00 2001
From: Kristóf Marussy <kristof@marussy.com>
Date: Thu, 29 Feb 2024 16:33:59 +0100
Subject: feat(language): validate assignment expressions

---
 .../language/validation/ProblemValidator.java      | 32 ++++++++++++
 .../tests/validation/AssignmentValidationTest.java | 61 ++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 subprojects/language/src/test/java/tools/refinery/language/tests/validation/AssignmentValidationTest.java

(limited to 'subprojects')

diff --git a/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java b/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java
index 560f612a..7f45bc20 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/validation/ProblemValidator.java
@@ -63,6 +63,8 @@ public class ProblemValidator extends AbstractProblemValidator {
 
 	public static final String UNSUPPORTED_ASSERTION_ISSUE = ISSUE_PREFIX + "UNSUPPORTED_ASSERTION";
 
+	public static final String INVALID_ASSIGNMENT_ISSUE = ISSUE_PREFIX + "INVALID_ASSIGNMENT";
+
 	@Inject
 	private ReferenceCounter referenceCounter;
 
@@ -493,4 +495,34 @@ public class ProblemValidator extends AbstractProblemValidator {
 			}
 		}
 	}
+
+	@Check
+	private void checkAssignmentExpr(AssignmentExpr assignmentExpr) {
+		var left = assignmentExpr.getLeft();
+		if (left == null) {
+			// Syntactically invalid, so we already emit an error.
+			return;
+		}
+		if (!(left instanceof VariableOrNodeExpr variableOrNodeExpr)) {
+			var message = "Left side of an assignment must be variable.";
+			acceptError(message, assignmentExpr, ProblemPackage.Literals.BINARY_EXPR__LEFT,
+					0, INVALID_ASSIGNMENT_ISSUE);
+			return;
+		}
+		var target = variableOrNodeExpr.getVariableOrNode();
+		if (target == null) {
+			// Syntactically invalid, so we already emit an error.
+			return;
+		}
+		if (target instanceof Parameter) {
+			var message = "Parameters cannot be assigned.";
+			acceptError(message, variableOrNodeExpr, ProblemPackage.Literals.VARIABLE_OR_NODE_EXPR__VARIABLE_OR_NODE,
+					0, INVALID_ASSIGNMENT_ISSUE);
+		}
+		if (target instanceof Node) {
+			var message = "Nodes cannot be assigned.";
+			acceptError(message, variableOrNodeExpr, ProblemPackage.Literals.VARIABLE_OR_NODE_EXPR__VARIABLE_OR_NODE,
+					0, INVALID_ASSIGNMENT_ISSUE);
+		}
+	}
 }
diff --git a/subprojects/language/src/test/java/tools/refinery/language/tests/validation/AssignmentValidationTest.java b/subprojects/language/src/test/java/tools/refinery/language/tests/validation/AssignmentValidationTest.java
new file mode 100644
index 00000000..a9e0e311
--- /dev/null
+++ b/subprojects/language/src/test/java/tools/refinery/language/tests/validation/AssignmentValidationTest.java
@@ -0,0 +1,61 @@
+/*
+ * SPDX-FileCopyrightText: 2024 The Refinery Authors <https://refinery.tools/>
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package tools.refinery.language.tests.validation;
+
+
+import com.google.inject.Inject;
+import org.eclipse.xtext.testing.InjectWith;
+import org.eclipse.xtext.testing.extensions.InjectionExtension;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import tools.refinery.language.model.tests.utils.ProblemParseHelper;
+import tools.refinery.language.tests.ProblemInjectorProvider;
+import tools.refinery.language.validation.ProblemValidator;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+
+@ExtendWith(InjectionExtension.class)
+@InjectWith(ProblemInjectorProvider.class)
+class AssignmentValidationTest {
+	@Inject
+	private ProblemParseHelper parseHelper;
+
+	@ParameterizedTest
+	@ValueSource(strings = {"""
+			pred foo(node a) <-> 5 is 5.
+			""", """
+			pred foo(node a) <-> b + 2 is 5.
+			""", """
+			pred foo(node a) <-> a is 5.
+			""", """
+			node(n).
+			pred foo(node a) <-> n is 5.
+			""", """
+			enum E { A, B }
+			pred foo(node a) <-> B is 5.
+			"""})
+	void invalidAssignmentTest(String text) {
+		var problem = parseHelper.parse(text);
+		var issues = problem.validate();
+		assertThat(issues, hasItem(hasProperty("issueCode", is(
+				ProblemValidator.INVALID_ASSIGNMENT_ISSUE
+		))));
+	}
+
+	@Test
+	void validAssignmentTest() {
+		var problem = parseHelper.parse("""
+				pred foo(node a) <-> b is 5.
+				""");
+		var issues = problem.validate();
+		assertThat(issues, not(hasItem(hasProperty("issueCode", is(
+				ProblemValidator.INVALID_ASSIGNMENT_ISSUE
+		)))));
+	}
+}
-- 
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