improve comments on jexl setup and future work

Author: johnbley

instrumentation/nocode/src/main/java/com/splunk/opentelemetry/instrumentation/nocode/JexlEvaluator.java

@@ -31,13 +31,16 @@ public class JexlEvaluator implements NocodeEvaluation.Evaluator {
   private final JexlEngine jexl;
 
   public JexlEvaluator() {
-    JexlFeatures features = new JexlFeatures().register(false).comparatorNames(false);
-    // The "unrestricted" permissions allows jexl to introspect on custom/non-stdlib classes
-    // for calling methods
+    JexlFeatures features =
+        new JexlFeatures()
+            .register(false) // don't support #register syntax
+            .comparatorNames(false); // don't support 'lt' as an alternative to '<'
     this.jexl =
         new JexlBuilder()
             .features(features)
+            // "unrestricted" means "can introspect on custom classes"
             .permissions(JexlPermissions.UNRESTRICTED)
+            // don't support ant syntax
             .antish(false)
             .create();
   }

instrumentation/nocode/src/main/java/com/splunk/opentelemetry/instrumentation/nocode/YamlParser.java

@@ -33,7 +33,7 @@
 
 public final class YamlParser {
   private static final Logger logger = Logger.getLogger(YamlParser.class.getName());
-  // FIXME support method override selection - e.g., with classfile method signature or something
+  // FUTURE support method override selection - e.g., with classfile method signature or something
   private static final String NOCODE_YMLFILE = "splunk.otel.instrumentation.nocode.yml.file";
 
   private final List<NocodeRules.Rule> instrumentationRules;
@@ -68,6 +68,7 @@ private static List<NocodeRules.Rule> loadUnsafe(String yamlFileName) throws Exc
       for (Object yamlBit : parsedYaml) {
         List<Map<String, Object>> rulesMap = (List<Map<String, Object>>) yamlBit;
         for (Map<String, Object> yamlRule : rulesMap) {
+          // FUTURE support more complex class selection (inherits-from, etc.)
           String className = yamlRule.get("class").toString();
           String methodName = yamlRule.get("method").toString();
           String spanName =