@Override
        public String getBinding(String identifier) {
            if (type.dimension(identifier).isPresent())
                return identifier; // dimension names are bound but not substituted in the generate context
            else
                return context.getBinding(identifier);
        }
A context which adds the bindings of the generate dimension names to the given context.
vespajlib/src/main/java/com/yahoo/tensor/functions/Generate.java