Initial support for static methods/fields on interfaces

1 files changed, 68 insertions, 0 deletions

diff --git a/src/main/java/org/zwobble/couscous/transforms/SplitStaticsFromInterface.java b/src/main/java/org/zwobble/couscous/transforms/SplitStaticsFromInterface.java
new file mode 100644
index 0000000..b2c88ea
--- /dev/null
+++ b/src/main/java/org/zwobble/couscous/transforms/SplitStaticsFromInterface.java
@@ -0,0 +1,68 @@
+package org.zwobble.couscous.transforms;
+
+import com.google.common.collect.Iterables;
+import org.zwobble.couscous.ast.*;
+import org.zwobble.couscous.ast.visitors.NodeTransformer;
+import org.zwobble.couscous.types.ScalarType;
+
+import java.util.*;
+
+import static org.zwobble.couscous.util.ExtraLists.eagerFilter;
+import static org.zwobble.couscous.util.ExtraLists.list;
+import static org.zwobble.couscous.util.ExtraSets.set;
+
+public class SplitStaticsFromInterface {
+    public static List<TypeNode> transform(List<TypeNode> typeNodes) {
+        List<TypeNode> result = new ArrayList<>();
+        Set<ScalarType> splitInterfaces = new HashSet<>();
+
+        for (TypeNode typeNode : typeNodes) {
+            if (isSplittable(typeNode)) {
+                splitInterfaces.add(typeNode.getName());
+                InterfaceNode interfaceNode = (InterfaceNode) typeNode;
+                result.add(ClassNode.declareClass(
+                    staticTypeFor(interfaceNode.getName()),
+                    list(),
+                    set(),
+                    interfaceNode.getFields(),
+                    interfaceNode.getStaticConstructor(),
+                    ConstructorNode.DEFAULT,
+                    eagerFilter(interfaceNode.getMethods(), method -> method.isStatic())
+                ));
+                result.add(InterfaceNode.declareInterface(
+                    interfaceNode.getName(),
+                    interfaceNode.getTypeParameters(),
+                    interfaceNode.getSuperTypes(),
+                    list(),
+                    list(),
+                    eagerFilter(interfaceNode.getMethods(), method -> !method.isStatic())
+                ));
+            } else {
+                result.add(typeNode);
+            }
+        }
+
+        NodeTransformer transformer = NodeTransformer.builder()
+            .transformReceiver((Receiver receiver) -> {
+                if (receiver instanceof StaticReceiver && splitInterfaces.contains(((StaticReceiver) receiver).getType())) {
+                    return StaticReceiver.staticReceiver(staticTypeFor(((StaticReceiver) receiver).getType()));
+                } else {
+                    return receiver;
+                }
+            })
+            .build();
+        return NodeTransformer.apply(transformer, result);
+    }
+
+    private static ScalarType staticTypeFor(ScalarType name) {
+        return ScalarType.of(name.getQualifiedName() + "_static");
+    }
+
+    private static boolean isSplittable(TypeNode typeNode) {
+        if (!(typeNode instanceof InterfaceNode)) {
+            return false;
+        }
+        InterfaceNode interfaceNode = (InterfaceNode) typeNode;
+        return !interfaceNode.getFields().isEmpty() || Iterables.any(interfaceNode.getMethods(), MethodNode::isStatic);
+    }
+}