feat(language): datatype declarations

Also changes ReferenceDeclaration to declare attributes, since reference and
attributes can only be distinguished at linking time.

5 files changed, 22 insertions, 33 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 f0d6c38c..a2fea627 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
+++ b/subprojects/language/src/main/java/tools/refinery/language/Problem.xtext
@@ -17,7 +17,7 @@ enum ModuleKind:
 
 Statement:
         ImportStatement | Assertion | ClassDeclaration | EnumDeclaration |
-        PredicateDefinition | /* FunctionDefinition | RuleDefinition | */
+        DatatypeDeclaration | PredicateDefinition | /* FunctionDefinition | RuleDefinition | */
         ScopeDeclaration | NodeDeclaration;
 
 ImportStatement:
@@ -27,7 +27,7 @@ ClassDeclaration:
         abstract?="abstract"? "class"
         name=Identifier
         ("extends" superTypes+=[Relation|QualifiedName] ("," superTypes+=[Relation|QualifiedName])*)?
-        ("{" (featureDeclarations+=FeatureDeclaration ";"?)* "}" | ".");
+        ("{" (featureDeclarations+=ReferenceDeclaration ";"?)* "}" | ".");
 
 EnumDeclaration:
         "enum"
@@ -37,8 +37,8 @@ EnumDeclaration:
 EnumLiteral returns Node:
         name=Identifier;
 
-FeatureDeclaration:
-        ReferenceDeclaration /* | AttributeDeclaration | FlagDeclaration */;
+DatatypeDeclaration:
+        "extern" "datatype" name=Identifier ".";
 
 enum ReferenceKind:
         REFERENCE="refers" | CONTAINMENT="contains" | CONTAINER="container";
@@ -53,15 +53,6 @@ ReferenceDeclaration:
 ReferenceMultiplicity returns Multiplicity:
         "[" Multiplicity "]";
 
-//enum PrimitiveType:
-//      INT="int" | REAL="real" | STRING="string";
-//
-//AttributeDeclaration:
-//      attributeType=PrimitiveType name=Identifier;
-//
-//FlagDeclaration:
-//      "bool" name=Identifier;
-
 PredicateDefinition:
         ("pred" | error?="error" "pred"?)
         name=Identifier
@@ -73,7 +64,7 @@ Conjunction:
         literals+=Expr ("," literals+=Expr)*;
 
 //FunctionDefinition:
-//      "fn" functionType=PrimitiveType name=Identifier
+//      "fn" functionType=[DatatypeDefinition|QualifiedName] name=Identifier
 //      "(" (parameters+=Parameter ("," parameters+=Parameter)*)? ")"
 //      ("=" cases+=Case (";" cases+=Case)*)?
 //      ".";
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 d905aa9a..efa77c50 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
@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ * SPDX-FileCopyrightText: 2021-2024 The Refinery Authors <https://refinery.tools/>
  *
  * SPDX-License-Identifier: EPL-2.0
  */
@@ -51,7 +51,7 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                 if (contents.isEmpty()) {
                         return null;
                 }
-                EObject object = contents.get(0);
+                EObject object = contents.getFirst();
                 if (object instanceof Problem problem) {
                         return problem;
                 }
@@ -71,10 +71,8 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                 for (var statement : problem.getStatements()) {
                         if (statement instanceof ClassDeclaration classDeclaration) {
                                 installOrRemoveNewNode(adapter, classDeclaration);
-                                for (var featureDeclaration : classDeclaration.getFeatureDeclarations()) {
-                                        if (featureDeclaration instanceof ReferenceDeclaration referenceDeclaration) {
-                                                installOrRemoveInvalidMultiplicityPredicate(adapter, classDeclaration, referenceDeclaration);
-                                        }
+                                for (var referenceDeclaration : classDeclaration.getFeatureDeclarations()) {
+                                        installOrRemoveInvalidMultiplicityPredicate(adapter, classDeclaration, referenceDeclaration);
                                 }
                         }
                 }
@@ -157,9 +155,8 @@ public class ProblemDerivedStateComputer implements IDerivedStateComputer {
                                 if (classDeclaration.isAbstract()) {
                                         abstractClassDeclarations.add(classDeclaration);
                                 }
-                                for (var featureDeclaration : classDeclaration.getFeatureDeclarations()) {
-                                        if (featureDeclaration instanceof ReferenceDeclaration referenceDeclaration &&
-                                                        ProblemUtil.hasMultiplicityConstraint(referenceDeclaration)) {
+                                for (var referenceDeclaration : classDeclaration.getFeatureDeclarations()) {
+                                        if (ProblemUtil.hasMultiplicityConstraint(referenceDeclaration)) {
                                                 referenceDeclarationsWithMultiplicity.add(referenceDeclaration);
                                         }
                                 }
diff --git a/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemDesugarer.java b/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemDesugarer.java
index 0bd1e50b..d45c8083 100644
--- a/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemDesugarer.java
+++ b/subprojects/language/src/main/java/tools/refinery/language/utils/ProblemDesugarer.java
@@ -87,11 +87,7 @@ public class ProblemDesugarer {
         private Collection<ReferenceDeclaration> doGetAllReferenceDeclarations(ClassDeclaration classDeclaration) {
                 Set<ReferenceDeclaration> referenceDeclarations = new HashSet<>();
                 for (ClassDeclaration superclass : getSuperclassesAndSelf(classDeclaration)) {
-                        for (FeatureDeclaration featureDeclaration : superclass.getFeatureDeclarations()) {
-                                if (featureDeclaration instanceof ReferenceDeclaration referenceDeclaration) {
-                                        referenceDeclarations.add(referenceDeclaration);
-                                }
-                        }
+            referenceDeclarations.addAll(superclass.getFeatureDeclarations());
                 }
                 return referenceDeclarations;
         }
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 f70893e0..6d6d65da 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
@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2021-2023 The Refinery Authors <https://refinery.tools/>
+ * SPDX-FileCopyrightText: 2021-2024 The Refinery Authors <https://refinery.tools/>
  *
  * SPDX-License-Identifier: EPL-2.0
  */
@@ -81,6 +81,9 @@ public final class ProblemUtil {
         }
 
         public static boolean hasMultiplicityConstraint(ReferenceDeclaration referenceDeclaration) {
+                if (referenceDeclaration.getReferenceType() instanceof DatatypeDeclaration) {
+                        return false;
+                }
                 var opposite = referenceDeclaration.getOpposite();
                 if (opposite != null && opposite.getKind() == ReferenceKind.CONTAINMENT) {
                         return false;
@@ -96,7 +99,8 @@ public final class ProblemUtil {
         }
 
         public static int getArity(Relation relation) {
-                if (relation instanceof ClassDeclaration || relation instanceof EnumDeclaration) {
+                if (relation instanceof ClassDeclaration || relation instanceof EnumDeclaration ||
+                                relation instanceof DatatypeDeclaration) {
                         return 1;
                 }
                 if (relation instanceof ReferenceDeclaration) {
@@ -116,7 +120,7 @@ public final class ProblemUtil {
                 return switch (kind) {
                         case CONTAINMENT -> false;
                         case CONTAINER -> true;
-                        case REFERENCE -> {
+                        case DEFAULT, REFERENCE -> {
                                 var opposite = referenceDeclaration.getOpposite();
                                 if (opposite == null) {
                                         yield false;
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 d9eb5fd3..560f612a 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
@@ -315,8 +315,9 @@ public class ProblemValidator extends AbstractProblemValidator {
 
         @Check
         public void checkReferenceType(ReferenceDeclaration referenceDeclaration) {
-                if (referenceDeclaration.getKind() == ReferenceKind.REFERENCE &&
-                                !ProblemUtil.isContainerReference(referenceDeclaration)) {
+                boolean isDefaultReference = referenceDeclaration.getKind() == ReferenceKind.DEFAULT &&
+                                !ProblemUtil.isContainerReference(referenceDeclaration);
+                if (isDefaultReference || referenceDeclaration.getKind() == ReferenceKind.REFERENCE) {
                         checkArity(referenceDeclaration, ProblemPackage.Literals.REFERENCE_DECLARATION__REFERENCE_TYPE, 1);
                         return;
                 }