@Override
        public TensorType getType(String name) {
            Optional<Integer> index = type.indexOfDimension(name);
            if (index.isPresent()) // this is the name of a dimension
                return TensorType.empty;
            else
                return context.getType(name);
        }
A context for generating all the values of a tensor produced by evaluating Generate.
This returns all the current index values as variables and falls back to delivering from the given
evaluation context.
vespajlib/src/main/java/com/yahoo/tensor/functions/Generate.java