We currently have generic handlers for parameters in the runtime package. These use either reflection or the swagger spec to generically handle any parameter.

A much better, though more difficult approach would be to generate the specific code to marshal and unmarshal each parameter from a query. We know the exact style, format and content for each parameter at generation time, so we only need a subset of the generic code to handle each, and that could be embedded without any conditional type logic where it's used.

The thought of the template code to do this, though, makes me shake with fear.