`paramset:lookup_param()` throws an error

[robbielyman]

lines discussion

this isn't a bug, per se, but it is a weird design choice that might be worth revisiting.

[catfact]

refererence

https://github.com/monome/norns/blob/main/lua/core/paramset.lua#L485

[catfact]

guess i agree.

everything else in the module follows a different pattern: return nil / do nothing, print a warning. (don't take the system down.)

and in use it sort of makes sense that you might call this without knowing if the index is valid

[Dewb]

I'd suggest something like

function ParamSet:lookup_param(index)
  if type(index) == "string" then
    local p = self.lookup[index]
    if p then 
      return self.params[p]
    else 
      print("pset: invalid param name: "..index)
      return nil
    end
  else
    local p = self.params[index] 
    if p then 
      return p
    else
      print("pset: invalid paramset index: "..index)
      return nil
  end
end

this is probably a safe change, because only scripts that crash will have changed behavior, and if they're not already testing for a nil result they'll likely still crash a line or two later.