feat(language): node constants in rule actions

1 files changed, 17 insertions, 1 deletions

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 7b392182..84af4ee6 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
@@ -153,6 +153,22 @@ public class ProblemValidator extends AbstractProblemValidator {
         }
 
         @Check
+        public void checkNodeAssertionArgumentConstants(NodeAssertionArgument argument) {
+                var rule = EcoreUtil2.getContainerOfType(argument, RuleDefinition.class);
+                if (rule == null) {
+                        return;
+                }
+                var variableOrNode = argument.getNode();
+                if (variableOrNode instanceof Node node && !ProblemUtil.isAtomNode(node)) {
+                        var name = node.getName();
+                        var message = ("Only atoms can be referenced in rule actions. " +
+                                        "Mark '%s' as an atom with the declaration 'atom %s.'").formatted(name, name);
+                        error(message, argument, ProblemPackage.Literals.NODE_ASSERTION_ARGUMENT__NODE,
+                                        INSIGNIFICANT_INDEX, NODE_CONSTANT_ISSUE);
+                }
+        }
+
+        @Check
         public void checkUniqueDeclarations(Problem problem) {
                 var relations = new ArrayList<Relation>();
                 var nodes = new ArrayList<Node>();
@@ -360,7 +376,7 @@ public class ProblemValidator extends AbstractProblemValidator {
                                                 INVALID_MODALITY_ISSUE);
                         }
                         if (parameter.getBinding() != ParameterBinding.SINGLE) {
-                                acceptError("Parameter binding annotations are only supported in rule definitions.", parameter,
+                                acceptError("Parameter binding annotations are only supported in decision rules.", parameter,
                                                 ProblemPackage.PARAMETER__BINDING, 0, INVALID_MODALITY_ISSUE);
                         }
                 }