refactor(language): shadow predicates instead of computed value operator

6 files changed, 71 insertions, 35 deletions

diff --git a/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext b/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
index 8d7d485b..cca94e66 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
+++ b/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
@@ -58,6 +58,7 @@ ReferenceMultiplicity returns Multiplicity:
         "[" Multiplicity "]";
 
 PredicateDefinition:
+        shadow?="shadow"?
         ("pred" | error?="error" "pred"?)
         name=Identifier
         "(" (parameters+=Parameter ("," parameters+=Parameter)*)? ")"
@@ -200,7 +201,6 @@ CastExprBody returns Expr:
 
 Atom:
         relation=[Relation|QualifiedName]
-        computed?="$"?
         transitiveClosure?=TRANSITIVE_CLOSURE?
         "(" (arguments+=Expr ("," arguments+=Expr)*)? ")";
 
@@ -297,7 +297,7 @@ Identifier:
 
 NonContainmentIdentifier:
         ID | "atom" | "multi" | "contained" | "problem" | "module" |
-        "datatype" | "aggregator" | "decision" | "propagation";
+        "datatype" | "aggregator" | "decision" | "propagation" | "computed";
 
 Real returns ecore::EDouble:
         EXPONENTIAL | INT "." (INT | EXPONENTIAL);
diff --git a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java
index d47863da..487e4ceb 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/parser/antlr/ProblemTokenSource.java
@@ -28,8 +28,6 @@ public class ProblemTokenSource implements TokenSource {
 
         private boolean seenId;
 
-        private boolean seenComputed;
-
         private boolean lastVisible;
 
         public ProblemTokenSource(TokenSource delegate) {
@@ -59,13 +57,10 @@ public class ProblemTokenSource implements TokenSource {
                         } else if (lastVisible && isQualifiedNameSeparator(token)) {
                                 token.setType(InternalProblemParser.RULE_QUALIFIED_NAME_SEPARATOR);
                         }
-                } else if (seenComputed && isPlusOrTransitiveClosure(token) && peekForTransitiveClosure()) {
-                        token.setType(InternalProblemParser.RULE_TRANSITIVE_CLOSURE);
                 }
                 lastVisible = isVisibleToken(token);
                 if (lastVisible) {
                         seenId = isIdentifier(token);
-                        seenComputed = isComputed(token);
                 }
                 return token;
         }
@@ -87,10 +82,6 @@ public class ProblemTokenSource implements TokenSource {
                 return token.getType() == InternalProblemParser.ColonColon;
         }
 
-        protected boolean isComputed(Token token) {
-                return token.getType() == InternalProblemParser.DollarSign;
-        }
-
         protected boolean isVisibleToken(Token token) {
                 int tokenId = token.getType();
                 return tokenId != InternalProblemParser.RULE_WS && tokenId != InternalProblemParser.RULE_SL_COMMENT &&
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemResourceDescriptionStrategy.java b/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemResourceDescriptionStrategy.java
index cad98d50..8ebd34a5 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemResourceDescriptionStrategy.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/ProblemResourceDescriptionStrategy.java
@@ -46,8 +46,8 @@ public class ProblemResourceDescriptionStrategy extends DefaultResourceDescripti
         public static final String MODULE_KIND = DATA_PREFIX + "MODULE_KIND";
         public static final String COLOR_RELATION = DATA_PREFIX + "COLOR_RELATION";
         public static final String COLOR_RELATION_TRUE = "true";
-        public static final String COMPUTED_VALUE = DATA_PREFIX + "COMPUTED_VALUE";
-        public static final String COMPUTED_VALUE_TRUE = "true";
+        public static final String SHADOW_PREDICATE = DATA_PREFIX + "COMPUTED_VALUE";
+        public static final String SHADOW_PREDICATE_TRUE = "true";
 
         @Inject
         private IQualifiedNameConverter qualifiedNameConverter;
@@ -165,8 +165,8 @@ public class ProblemResourceDescriptionStrategy extends DefaultResourceDescripti
                 if (ProblemUtil.isError(eObject)) {
                         builder.put(ERROR_PREDICATE, ERROR_PREDICATE_TRUE);
                 }
-                if (ProblemUtil.isComputedValue(eObject)) {
-                        builder.put(COMPUTED_VALUE, COMPUTED_VALUE_TRUE);
+                if (ProblemUtil.isShadow(eObject)) {
+                        builder.put(SHADOW_PREDICATE, SHADOW_PREDICATE_TRUE);
                 }
                 var documentationMap = documentationCommentParser.parseDocumentation(eObject);
                 builder.putAll(documentationMap);
@@ -178,7 +178,8 @@ public class ProblemResourceDescriptionStrategy extends DefaultResourceDescripti
                         return !ProblemUtil.isMultiNode(node);
                 }
                 if (eObject instanceof PredicateDefinition predicateDefinition) {
-                        return !ProblemUtil.isInvalidMultiplicityConstraint(predicateDefinition);
+                        return !ProblemUtil.isInvalidMultiplicityConstraint(predicateDefinition) &&
+                                        !ProblemUtil.isComputedValuePredicate(predicateDefinition);
                 }
                 return true;
         }
diff --git a/subprojects/language/src/main/java/tools/refinery/language/resource/state/ProblemDerivedStateComputer.java b/subprojects/language/src/main/java/tools/refinery/language/resource/state/ProblemDerivedStateComputer.java
index efa77c50..6b9b76d1 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/resource/state/ProblemDerivedStateComputer.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/resource/state/ProblemDerivedStateComputer.java
@@ -22,6 +22,7 @@ import tools.refinery.language.utils.ProblemUtil;
 
 import java.util.*;
 import java.util.function.Function;
+import java.util.function.UnaryOperator;
 
 @Singleton
 public class ProblemDerivedStateComputer implements IDerivedStateComputer {
@@ -59,7 +60,7 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
         }
 
         protected void installDerivedProblemState(Problem problem, Adapter adapter, boolean preLinkingPhase) {
-                installDerivedClassDeclarationState(problem, adapter);
+                installDerivedDeclarationState(problem, adapter);
                 if (preLinkingPhase) {
                         return;
                 }
@@ -67,13 +68,15 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                 derivedVariableComputer.installDerivedVariables(problem, nodeNames);
         }
 
-        protected void installDerivedClassDeclarationState(Problem problem, Adapter adapter) {
+        protected void installDerivedDeclarationState(Problem problem, Adapter adapter) {
                 for (var statement : problem.getStatements()) {
                         if (statement instanceof ClassDeclaration classDeclaration) {
                                 installOrRemoveNewNode(adapter, classDeclaration);
                                 for (var referenceDeclaration : classDeclaration.getFeatureDeclarations()) {
                                         installOrRemoveInvalidMultiplicityPredicate(adapter, classDeclaration, referenceDeclaration);
                                 }
+                        } else if (statement instanceof PredicateDefinition predicateDefinition) {
+                                installOrRemoveComputedValuePredicate(adapter, predicateDefinition);
                         }
                 }
         }
@@ -118,6 +121,27 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                 }
         }
 
+        protected void installOrRemoveComputedValuePredicate(Adapter adapter, PredicateDefinition predicateDefinition) {
+                if (ProblemUtil.hasComputedValue(predicateDefinition)) {
+                        var computedValue = adapter.createComputedValuePredicateIfAbsent(predicateDefinition, key -> {
+                                var predicate = ProblemFactory.eINSTANCE.createPredicateDefinition();
+                                predicate.setShadow(true);
+                                predicate.setName("definition");
+                                return predicate;
+                        });
+                        var parameters = computedValue.getParameters();
+                        parameters.clear();
+                        parameters.addAll(EcoreUtil.copyAll(predicateDefinition.getParameters()));
+                        predicateDefinition.setComputedValue(computedValue);
+                } else {
+                        var computedValue = predicateDefinition.getComputedValue();
+                        if (computedValue != null) {
+                                predicateDefinition.setComputedValue(null);
+                                adapter.removeComputedValuePredicate(computedValue);
+                        }
+                }
+        }
+
         protected Set<String> installDerivedNodes(Problem problem) {
                 var collector = nodeNameCollectorProvider.get();
                 collector.collectNodeNames(problem);
@@ -148,6 +172,7 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
         protected void discardDerivedProblemState(Problem problem, Adapter adapter) {
                 var abstractClassDeclarations = new HashSet<ClassDeclaration>();
                 var referenceDeclarationsWithMultiplicity = new HashSet<ReferenceDeclaration>();
+                var predicateDefinitionsWithComputedValue = new HashSet<PredicateDefinition>();
                 problem.getNodes().clear();
                 for (var statement : problem.getStatements()) {
                         if (statement instanceof ClassDeclaration classDeclaration) {
@@ -160,9 +185,13 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                                                 referenceDeclarationsWithMultiplicity.add(referenceDeclaration);
                                         }
                                 }
+                        } else if (statement instanceof PredicateDefinition predicateDefinition &&
+                                        ProblemUtil.hasComputedValue(predicateDefinition)) {
+                                predicateDefinitionsWithComputedValue.add(predicateDefinition);
                         }
                 }
-                adapter.retainAll(abstractClassDeclarations, referenceDeclarationsWithMultiplicity);
+                adapter.retainAll(abstractClassDeclarations, referenceDeclarationsWithMultiplicity,
+                                predicateDefinitionsWithComputedValue);
                 derivedVariableComputer.discardDerivedVariables(problem);
         }
 
@@ -185,6 +214,7 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
         protected static class Adapter extends AdapterImpl {
                 private final Map<ClassDeclaration, Node> newNodes = new HashMap<>();
                 private final Map<ReferenceDeclaration, PredicateDefinition> invalidMultiplicityPredicates = new HashMap<>();
+                private final Map<PredicateDefinition, PredicateDefinition> computedValuePredicates = new HashMap<>();
 
                 public Node createNewNodeIfAbsent(ClassDeclaration classDeclaration,
                                                                                   Function<ClassDeclaration, Node> createNode) {
@@ -205,10 +235,21 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                         invalidMultiplicityPredicates.remove(referenceDeclaration);
                 }
 
+                public PredicateDefinition createComputedValuePredicateIfAbsent(
+                                PredicateDefinition predicateDefinition, UnaryOperator<PredicateDefinition> createPredicate) {
+                        return computedValuePredicates.computeIfAbsent(predicateDefinition, createPredicate);
+                }
+
+                public void removeComputedValuePredicate(PredicateDefinition predicateDefinition) {
+                        computedValuePredicates.remove(predicateDefinition);
+                }
+
                 public void retainAll(Collection<ClassDeclaration> abstractClassDeclarations,
-                                                          Collection<ReferenceDeclaration> referenceDeclarationsWithMultiplicity) {
+                                                          Collection<ReferenceDeclaration> referenceDeclarationsWithMultiplicity,
+                                                          Collection<PredicateDefinition> predicateDefinitionsWithComputedValue) {
                         newNodes.keySet().retainAll(abstractClassDeclarations);
                         invalidMultiplicityPredicates.keySet().retainAll(referenceDeclarationsWithMultiplicity);
+                        computedValuePredicates.keySet().retainAll(predicateDefinitionsWithComputedValue);
                 }
 
                 @Override
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemUtil.java b/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemUtil.java
index 7e7de681..c2c19d74 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemUtil.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemUtil.java
@@ -53,8 +53,8 @@ public final class ProblemUtil {
                 return eObject instanceof PredicateDefinition predicateDefinition && predicateDefinition.isError();
         }
 
-        public static boolean isComputedValue(EObject eObject) {
-                return eObject instanceof PredicateDefinition predicateDefinition && !predicateDefinition.getBodies().isEmpty();
+        public static boolean isShadow(EObject eObject) {
+                return eObject instanceof PredicateDefinition predicateDefinition && predicateDefinition.isShadow();
         }
 
         public static boolean isAtomNode(Node node) {
@@ -77,9 +77,12 @@ public final class ProblemUtil {
                 return node.eContainingFeature() == ProblemPackage.Literals.NODE_DECLARATION__NODES;
         }
 
-        public static boolean isInvalidMultiplicityConstraint(PredicateDefinition predicateDefinition) {
-                return predicateDefinition.eContainingFeature() ==
-                                ProblemPackage.Literals.REFERENCE_DECLARATION__INVALID_MULTIPLICITY;
+        public static boolean isInvalidMultiplicityConstraint(Relation relation) {
+                return relation.eContainingFeature() == ProblemPackage.Literals.REFERENCE_DECLARATION__INVALID_MULTIPLICITY;
+        }
+
+        public static boolean isComputedValuePredicate(Relation relation) {
+                return relation.eContainingFeature() == ProblemPackage.Literals.PREDICATE_DEFINITION__COMPUTED_VALUE;
         }
 
         public static boolean hasMultiplicityConstraint(ReferenceDeclaration referenceDeclaration) {
@@ -100,6 +103,10 @@ public final class ProblemUtil {
                 return true;
         }
 
+        public static boolean hasComputedValue(PredicateDefinition predicateDefinition) {
+                return !predicateDefinition.isShadow() && !predicateDefinition.getBodies().isEmpty();
+        }
+
         public static boolean isTypeLike(Relation relation) {
                 if (relation instanceof ClassDeclaration || relation instanceof EnumDeclaration ||
                                 relation instanceof DatatypeDeclaration) {
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 7114b693..58d86fa0 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
@@ -49,7 +49,7 @@ public class ProblemValidator extends AbstractProblemValidator {
         public static final String INVALID_MODALITY_ISSUE = ISSUE_PREFIX + "INVALID_MODALITY";
         public static final String INVALID_RULE_ISSUE = ISSUE_PREFIX + "INVALID_RULE";
         public static final String INVALID_TRANSITIVE_CLOSURE_ISSUE = ISSUE_PREFIX + "INVALID_TRANSITIVE_CLOSURE";
-        public static final String INVALID_COMPUTED_VALUE_ISSUE = ISSUE_PREFIX + "INVALID_COMPUTED_VALUE";
+        public static final String SHADOW_RELATION_ISSUE = ISSUE_PREFIX + "SHADOW_RELATION";
         public static final String UNSUPPORTED_ASSERTION_ISSUE = ISSUE_PREFIX + "UNSUPPORTED_ASSERTION";
         public static final String UNKNOWN_EXPRESSION_ISSUE = ISSUE_PREFIX + "UNKNOWN_EXPRESSION";
         public static final String INVALID_ASSIGNMENT_ISSUE = ISSUE_PREFIX + "INVALID_ASSIGNMENT";
@@ -426,16 +426,12 @@ public class ProblemValidator extends AbstractProblemValidator {
                         acceptError(message, atom, ProblemPackage.Literals.ATOM__TRANSITIVE_CLOSURE, 0,
                                         INVALID_TRANSITIVE_CLOSURE_ISSUE);
                 }
-                if (atom.isComputed()) {
-                        var target = atom.getRelation();
-                        if (target != null && !target.eIsProxy() && !ProblemUtil.isComputedValue(target)) {
-                                var message = "Relation '%s' has no computed value.".formatted(target.getName());
-                                acceptError(message, atom, ProblemPackage.Literals.ATOM__COMPUTED, 0, INVALID_COMPUTED_VALUE_ISSUE);
-                        }
+                var target = atom.getRelation();
+                if (target != null && !target.eIsProxy() && ProblemUtil.isShadow(target)) {
                         var definitionContext = EcoreUtil2.getContainerOfType(atom, ParametricDefinition.class);
-                        if (!(definitionContext instanceof RuleDefinition)) {
-                                var message = "Computed value references may only appear in rule definitions.";
-                                acceptError(message, atom, ProblemPackage.Literals.ATOM__COMPUTED, 0, INVALID_COMPUTED_VALUE_ISSUE);
+                        if (!(definitionContext instanceof RuleDefinition)){
+                                var message = "Shadow relation '%s' may only appear in rule definitions.".formatted(target.getName());
+                                acceptError(message, atom, ProblemPackage.Literals.ATOM__RELATION, 0, SHADOW_RELATION_ISSUE);
                         }
                 }
         }