Groovy: support GStrings as identifiers

Author: greg-at-moderne

rewrite-groovy/src/main/java/org/openrewrite/groovy/GroovyParserVisitor.java

@@ -2388,11 +2388,14 @@ public void visitAttributeExpression(AttributeExpression attr) {
             queue.add(insideParentheses(attr, fmt -> {
                 Expression target = doVisit(attr.getObjectExpression());
                 Space beforeDot = attr.isSafe() ? sourceBefore("?.") : sourceBefore(attr.isSpreadSafe() ? "*." : ".");
+                int saveCursor = cursor;
                 J name = doVisit(attr.getProperty());
                 if (name instanceof J.Literal) {
                     String nameStr = ((J.Literal) name).getValueSource();
                     assert nameStr != null;
                     name = new J.Identifier(randomId(), name.getPrefix(), Markers.EMPTY, emptyList(), nameStr, null, null);
+                } else if (name instanceof G.GString) {
+                    name = gStringAsIdentifier((G.GString) name, saveCursor);
                 }
                 if (attr.isSpreadSafe()) {
                     name = name.withMarkers(name.getMarkers().add(new StarDot(randomId())));
@@ -2409,10 +2412,13 @@ public void visitPropertyExpression(PropertyExpression prop) {
             queue.add(insideParentheses(prop, fmt -> {
                 Expression target = doVisit(prop.getObjectExpression());
                 Space beforeDot = prop.isSpreadSafe() ? sourceBefore("*.") : sourceBefore(prop.isSafe() ? "?." : ".");
+                int saveCursor = cursor;
                 J name = doVisit(prop.getProperty());
                 if (name instanceof J.Literal) {
                     J.Literal nameLiteral = ((J.Literal) name);
                     name = new J.Identifier(randomId(), name.getPrefix(), Markers.EMPTY, emptyList(), nameLiteral.getValueSource(), nameLiteral.getType(), null);
+                } else if (name instanceof G.GString) {
+                    name = gStringAsIdentifier((G.GString) name, saveCursor);
                 }
                 if (prop.isSpreadSafe()) {
                     name = name.withMarkers(name.getMarkers().add(new StarDot(randomId())));
@@ -2423,6 +2429,12 @@ public void visitPropertyExpression(PropertyExpression prop) {
             }));
         }
 
+        private J.Identifier gStringAsIdentifier(G.GString gString, int saveCursor) {
+            int gStringStart = indexOfNextNonWhitespace(saveCursor, source);
+            String text = source.substring(gStringStart, cursor);
+            return new J.Identifier(randomId(), gString.getPrefix(), Markers.EMPTY, emptyList(), text, gString.getType(), null);
+        }
+
         @Override
         public void visitRangeExpression(RangeExpression range) {
             queue.add(insideParentheses(range, fmt -> new G.Range(randomId(), fmt, Markers.EMPTY,

rewrite-groovy/src/test/java/org/openrewrite/groovy/tree/FieldAccessTest.java

@@ -72,4 +72,17 @@ class Test {
           )
         );
     }
+
+    @Test
+    void dynamicPropertyNameWithGString() {
+        rewriteRun(
+          groovy(
+            """
+              def f(node, key) {
+                  node."@$key"
+              }
+              """
+          )
+        );
+    }
 }