typedef struct {
    const char* uri;
    LV2_URID    urid;
    LV2_Atom*   value;
} StateKey;

static LV2_Handle
instantiate(const LV2_Descriptor*     descriptor,
            double                    rate,
            const char*               path,
            const LV2_Feature* const* features)
{
    /* ... */
    State*   state        = &self->state;
    StateKey state_dict[] = {
        { EG_PARAMS_URI "#int",    0, (LV2_Atom*)&state->aint },
        { EG_PARAMS_URI "#long",   0, (LV2_Atom*)&state->along },
        { EG_PARAMS_URI "#float",  0, (LV2_Atom*)&state->afloat },
        { EG_PARAMS_URI "#double", 0, (LV2_Atom*)&state->adouble },
        { EG_PARAMS_URI "#bool",   0, (LV2_Atom*)&state->abool },
        { EG_PARAMS_URI "#string", 0, (LV2_Atom*)&state->astring },
        { EG_PARAMS_URI "#path",   0, (LV2_Atom*)&state->apath },
        { EG_PARAMS_URI "#lfo",    0, (LV2_Atom*)&state->lfo },
        { EG_PARAMS_URI "#spring", 0, (LV2_Atom*)&state->spring },
        { NULL, 0, NULL }
    };

    for (StateKey* entry = state_dict; entry->uri; entry++) {
        entry->urid = self->map->map(self->map->handle, entry->uri);
    }

    /* ... */
}