MobileRead Forums - View Single Post - python templates (was possible template functions)

un_pogaz · 10-08-2022, 05:58 AM

Wait wait wait.
2 seconds. Pause.
Tell me if I'm wrong, but maybe I have a better idea.

Currently, the 'Template functions' and the 'Stored template' are saved a the same place in the DB table "preferences>user_template_functions". In order to be able to sort out what is what, Calibre uses the number of arguments of these: 0 is a 'Stored template' ; 1+ is 'Template functions'.
That's why you can't define 'Template functions' with 0 arguments.
I have the impression that all this thing of python: is a way to circumvent this limitation.
What if we treat the cause rather than the symptoms?

What I suggest is that we revise the way we save this in the DB.
Let's save separately 'Template functions' and 'Stored template' in their own preferences entry. Thus we can define functions with 0 arguments. We just need to do a version check of the DB and a data migration.

So, I agree that this poses a problem of the assenting compatibility (you can't load a +6.7 DB with 5.0 Calibre without a nice mess in your template), but I think, perhaps, that it will be much easier to implement this than python: with the different syntax highlighting changes it announces.
But it would be necessary to see with Kovid.

10-08-2022, 05:58 AM	#7
un_pogaz Chalut o/ Posts: 446 Karma: 672378 Join Date: Dec 2017 Device: Kobo	Wait wait wait. 2 seconds. Pause. Tell me if I'm wrong, but maybe I have a better idea. Currently, the 'Template functions' and the 'Stored template' are saved a the same place in the DB table "preferences>user_template_functions". In order to be able to sort out what is what, Calibre uses the number of arguments of these: 0 is a 'Stored template' ; 1+ is 'Template functions'. That's why you can't define 'Template functions' with 0 arguments. I have the impression that all this thing of python: is a way to circumvent this limitation. What if we treat the cause rather than the symptoms? What I suggest is that we revise the way we save this in the DB. Let's save separately 'Template functions' and 'Stored template' in their own preferences entry. Thus we can define functions with 0 arguments. We just need to do a version check of the DB and a data migration. So, I agree that this poses a problem of the assenting compatibility (you can't load a +6.7 DB with 5.0 Calibre without a nice mess in your template), but I think, perhaps, that it will be much easier to implement this than python: with the different syntax highlighting changes it announces. But it would be necessary to see with Kovid. Last edited by un_pogaz; 10-08-2022 at 06:06 AM.