Feat/ref at root level; anonymous section

index.html

@@ -115,7 +115,7 @@
               timer = setTimeout(() => {
                 const theme =
                   localStorage.getItem(`${location.hostname}-zenuml-theme`) ||
-                  "theme-idle-afternoon";
+                  "theme-default";
                 window.zenUml
                   .render(cm.getValue(), {
                     theme,

src/components/DiagramFrame/SeqDiagram/MessageLayer/Block/Statement/Fragment/FragmentSection.vue

@@ -67,9 +67,7 @@ export default {
     const atom = computed(() => section.value?.atom()?.getFormattedText());
     const blockInSection = computed(() => braceBlock.value?.block());
 
-    const label = computed(
-      () => atom.value ?? capitalize(section.value.SECTION()),
-    );
+    const label = computed(() => atom.value ?? capitalize("section"));
 
     return {
       label,

src/components/DiagramFrame/SeqDiagram/MessageLayer/MessageLayer.spec.js

@@ -31,6 +31,6 @@ describe("MessageLayer", () => {
     expect(messageLayerWrapper.find(".pt-24").exists()).toBeTruthy();
   });
   it("gets participant names", async () => {
-    expect(messageLayerWrapper.vm.origin).toBeNull();
+    expect(messageLayerWrapper.vm.origin).toBe("_STARTER_");
   });
 });

src/components/DiagramFrame/SeqDiagram/MessageLayer/MessageLayer.vue

@@ -3,7 +3,6 @@ TODO: we may need to consider the width of self message on right most participan
 <template>
   <div class="message-layer relative z-30 pt-24 pb-10">
     <block
-      v-if="!!origin"
       :context="context"
       :style="{ 'padding-left': paddingLeft + 'px' }"
       :origin="origin"
@@ -35,7 +34,7 @@ const paddingLeft = computed(() => {
 
 const origin = computed(() => {
   const ownableMessages = AllMessages(rootContext.value);
-  if (ownableMessages.length === 0) return null;
+  if (ownableMessages.length === 0) return _STARTER_;
   return ownableMessages[0].from || _STARTER_;
 });
 

src/g4/sequenceParser.g4

@@ -127,9 +127,11 @@ critical
   | CRITICAL
  ;
 
+// section(name) {}
 section
   : SECTION (OPAR atom? CPAR)? braceBlock
-  | SECTION
+  | braceBlock    // allows anonymous section. This is mostly for error tolerance (e.g. ref(x) { m1 }).
+  | SECTION       // Error tolerance for incomplete section
  ;
 
 creation