Conversation started Feb 26, 2020 at 16:04.
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Feb 26, 2020 16:04
@MathieuGuindon I just realized a question about VBA design. Would you agree that if you have a class that has no state, does it really want to be just a module?
FreeMan
FreeMan
@this yeah, but I don't want to tell a tale of any sort, temp or otherwise...
@this I asked that (not in so many words) a few days ago. Never got a response from the class...
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@FreeMan Sorry missed that. My guts says that if there's no state, there's no need for instance, and instancing is a new complexity.
I'm sure you can have classes with no internal data. An example would be to receive or to fire events. But that's not what I am thinking of having a state.
Mathieu Guindon
Mathieu Guindon
@this in theory, yes - it's basically a static class. In practice, its members are now exposed as macros and UDFs, and if I don't want that, even with Option Private Module (which merely hides the members from view, but they can still be invoked)
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WTF
FreeMan
FreeMan
that's pretty much what I thought, but... Mug's code review appears to me to have a stateless class
Mathieu Guindon
Mathieu Guindon
Feb 26, 2020 16:10
Yep, that's one
M.Doerner
M.Doerner
If the class implements an interface, it really does not want to be a module.
It is basically a strategy.
Mathieu Guindon
Mathieu Guindon
^
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Thinking about it - the Option Private Module prevents access from outside the project but not within. The host has the project so I guess it's "within". :\
M.Doerner
M.Doerner
I write tons of such classes.
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In this case, there's no interfaces involved, but you're correct that if I find it needing an interface, then I'd have to convert it to a class proper
In which case such conversion is trivial.
M.Doerner
M.Doerner
Feb 26, 2020 16:11
At least, with Option Private Module the procedures do not appear in the selection in the macros window.
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(converting class to module is not always trivial, though)
Mathieu Guindon
Mathieu Guindon
@M.Doerner yeah but if you know the name you can just type it in ...and it runs
..which makes Option Private Module marginally useful IMO
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Confirmed the same behavior in Access
So it's really only good for blocking other projects from calling the function.
Mathieu Guindon
Mathieu Guindon
also, isn't a module just a crippled class?
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I don't think so.
at low level, there are no classes.
Mathieu Guindon
Mathieu Guindon
Feb 26, 2020 16:15
oh
I had it the other way around
M.Doerner
M.Doerner
@MathieuGuindon What did you expect in Excel? After all, you can invoke private methods there.
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Classes only hide the fact that we are doing stuff like someClass::someMethod(someClass* self, ...);
Mathieu Guindon
Mathieu Guindon
@this good point
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VBA, being a bit older shows more of the C/C++ "root" than Java or C# does.
 
Conversation ended Feb 26, 2020 at 16:16.