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

Nick Mazuk nick at nickmazuk.com
Wed Aug 24 18:42:17 CEST 2022 

This seems like a good plan to me.

On Wed, Aug 24, 2022 at 8:58 AM, Robert Patterson < robert at robertgpatterson.com > wrote:

> 
> Instead of pcall, you do:
> 
> 
> if finenv.RawFinaleVersion >= <min-vers> then
> do something
> end
> 
> 
> It doesn't seem much worse than null checking, and it shows what's really
> going on. This could all be encapsulated in a client library of course.
> 
> 
> 
> On Wed, Aug 24, 2022 at 10:51 AM Robert Patterson < robert@ robertgpatterson.
> com ( robert at robertgpatterson.com ) > wrote:
> 
> 
>> I have been experimenting with throwing an error out of C++ this morning ,
>> and it works seamlessly exactly as one would hope. I much prefer an error
>> message that says, "modula.lua line 420: Finale 26.9 required". (To make
>> up a Finale version.)
>> 
>> 
>> Plus, you'll only have to use pcall if you are unwilling to specify
>> MinFinaleVersion in your plugindef.
>> 
>> 
>> 
>> 
>> On Wed, Aug 24, 2022 at 10:26 AM Nick Mazuk < nick@ nickmazuk. com (
>> nick at nickmazuk.com ) > wrote:
>> 
>> 
>>> 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@ robertgpatterson.
>>> com ( 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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