code: @SuppressWarnings("unchecked")
      private static <V> V resolve(ProvidenceConfigContext context,
                                   Token token,
                                   Tokenizer tokenizer,
                                   PDescriptor descriptor) throws TokenizerException {
          Object value = resolveAny(context, token, tokenizer);
          if (value == null) {
              return null;
          }
          return (V) asType(descriptor, value);
      }
docs: Resolve a value reference.
  
  @param context The parsing context.
  @param token The ID token to look for.
  @param tokenizer The tokenizer.
  @param descriptor The item descriptor.
  @return The value at the given key, or exception if not found.