[JW Lua] RFC: Adding Methods/Properties to RGP Lua that only exist in certain Finale versions

Wed Aug 24 17:25:13 CEST 2022

Throwing an error might be redundant. For instance, if the following prints out nil (for instance, if the method doesn't exist on the object):

local entry = finale.FCEntry()

print(entry.FooBar)

then the following will already be thrown an error since nil is not a function:

local entry = finale.FCEntry()

entry:FooBar() — error!

The only advantage I can think of by having RGP Lua throw an error if you even access it is that you'll potentially get more meaningful error messages as a user. As a developer, the plugin will still tell you exactly what line of code threw the error. However, it has the disadvantage that you must use pcall to capture the error and you cannot simply check if the method exists or not (which developers should be doing anyways for any newly added features to RGP Lua).

On Wed, Aug 24, 2022 at 5:24 AM, Robert Patterson < robert at robertgpatterson.com > wrote:

> 
> Throwing an error is a good idea that I hadn't thought of. However, these
> errors would have to be thrown out of the PDK Framework, which is not Lua.
> So far, there is no try/catch/throw in the PDK Framework codebase. That is
> not to say we couldn't start using it, but it will require approvals from
> the other clients that share that code.
> 
> 
> Meanwhile, if the function is missing you'll get the same behavior. It
> just won't have as helpful an error message. And by leaving it missing,
> you don't have to resort to pcall. You can simply test if it is there.
> 
> 
> 
> On Wed, Aug 24, 2022 at 6:18 AM Daniel Grunwald < dgr@ leng. de (
> dgr at leng.de ) > wrote:
> 
> 
>> 
>> 
>> Hi there,
>> 
>> 
>> 
>> it seems my first reply didn't get through. So I repeat it. I case you
>> receive this twice you know why.
>> 
>> 
>> 
>> I am a lua novice having no actual experience in lua so my idea might be
>> foolish. However from what I learned in terms of clean code in other
>> languages I would prefer to raise an error instead of not providing the
>> function.
>> In order to deal with this users will have to use pcall, as described in https:/
>> / www. lua. org/ pil/ 8. 4. html ( https://www.lua.org/pil/8.4.html )
>> 
>> 
>> 
>> Although not knowing if it really is (by lack experience) to me it sounds
>> like a cleaner approach.
>> 
>> 
>> 
>> However if you like to use the nil-approach I suggest putting "OrNil" as
>> suffix to the function's name so the name indicates it possibly being nil.
>> 
>> 
>> 
>> 
>> Hope this was helpful.
>> 
>> 
>> 
>> Best regards
>> Daniel
>> 
>> 
>> 
>> Von meinem Xperia™ von Sony-Smartphone gesendet
>> 
>> 
>> 
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>> Today 's Topics:
>> 
>> 1. RFC: Adding Methods/Properties to RGP Lua that only exist in
>> certain Finale versions (Robert Patterson)
>> 
>> 
>> ----------------------------------------------------------------------
>> 
>> Message: 1
>> Date: Mon , 22 Aug 2022 15:03: 15 -0500 ( tel:15%20-0500 )
>> From: Robert Patterson < robert@ robertgpatterson. com (
>> robert at robertgpatterson.com ) >
>> To: "The JW Lua script plug-in." < jwlua@ jwmusic. nu ( jwlua at jwmusic.nu )
>> >
>> Subject: [JW Lua] RFC: Adding Methods/Properties to RGP Lua that only
>> exist in certain Finale versions
>> Message-ID:
>> < CAACnceu23XaymU4XNBZQ-1e6wDdP5xP6-ht8fdk3trUduahrUA@ mail. gmail. com (
>> CAACnceu23XaymU4XNBZQ-1e6wDdP5xP6-ht8fdk3trUduahrUA at mail.gmail.com ) >
>> Content-Type: text/plain; charset="utf-8"
>> 
>> I will soon be adding to RGP Lua some methods and properties that are not
>> available before a certain Finale version. Previously when this has
>> happened, the methods and properties appear in all Finale versions but
>> return a default value in earlier Finale versions where they aren't
>> supported. Until now there has always been an appropriate default value.
>> 
>> However, these new methods and properties I plan to add do not have useful
>> 
>> default values in earlier Finale versions. In fact, it would be a bad idea
>> 
>> to return anything at all unless running in an supported Finale version.
>> 
>> To me the best solution would appear to be not to hook up these methods
>> and
>> properties to Lua if the Finale version doesn't support them. But that
>> means, in perpetuity, Lua programmers will have to check them for `nil`
>> before calling them. Does anyone have other/better ideas?
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