On 9/23/24 22:51, Dan Sommers via Python-list wrote:

On 2024-09-23 at 19:00:10 +0100,
Barry Scott <barry@barrys-emacs.org> wrote:

On 21 Sep 2024, at 11:40, Dan Sommers via Python-list <python-list@python.org> wrote:

But once your code gets big the disciple of using classes helps
maintenance. Code with lots of globals is problematic.

Even before your code gets big, discipline helps maintenance. :-)

Every level of your program has globals. An application with too many classes is no better (or worse) than a class with too many methods, or a module with too many functions. Insert your own definitions of (and tolerances for) "too many," which will vary in flexibility.

I think the need of classes comes when you need objects thus a set of
variables with an identity and that may be created N times. Classes are
object factories.

A second aspect is inheritance: classes may inherit from other classes
and reuse existing functionality and data structures for their objects.

In cases where you only need to encapsulate a single set of data and
functions modules are the best choice.

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Hi,

Apologies if the following description is to brief - I can expand if no
one knows what I'm on about, but maybe a short description is enough.

I am developing a command line application using Typer. Most commands
need to do something in a database and also do LDAP stuff. Currently
each command creates its own Database and LDAP objects, since each
command forms an entry point to the program.

With Typer, is there a way I can define the equivalent of class
attributes at a single point which are then available to all commands?

Cheers,

Loris

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On 20 Sep 2024, at 21:01, Loris Bennett via Python-list <python-list@python.org> wrote:

Hi,

Apologies if the following description is to brief - I can expand if no
one knows what I'm on about, but maybe a short description is enough.

I am developing a command line application using Typer. Most commands
need to do something in a database and also do LDAP stuff. Currently
each command creates its own Database and LDAP objects, since each
command forms an entry point to the program.

With Typer, is there a way I can define the equivalent of class
attributes at a single point which are then available to all commands?

I do not know typer. But the general solution is to create an instance of your class
and tell typer to call member function of the instance.

app = Application()
…
typer.set_callback(app.my_handler)

Barry

Cheers,

Loris

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On 2024-09-21 at 06:38:05 +0100,
Barry via Python-list <python-list@python.org> wrote:

On 20 Sep 2024, at 21:01, Loris Bennett via Python-list <python-list@python.org> wrote:

Hi,

Apologies if the following description is to brief - I can expand if no
one knows what I'm on about, but maybe a short description is enough.

I am developing a command line application using Typer. Most commands
need to do something in a database and also do LDAP stuff. Currently
each command creates its own Database and LDAP objects, since each
command forms an entry point to the program.

With Typer, is there a way I can define the equivalent of class
attributes at a single point which are then available to all commands?

I do not know typer. But the general solution is to create an instance of your class
and tell typer to call member function of the instance.

app = Application()
…
typer.set_callback(app.my_handler)

Despite the fact that "everything is an object" in Python, you don't
have to put data or functions inside classes or objects. I also know
nothing about Typer, but there's nothing wrong with functions in a
module.

There's also nothing wrong with writing a function that creates and
returns the database and LDAP connections (perhas as instances of application-level classes), amd calling that function from within each
command.

DRY. Yeah, yeah, yeah. :-/ So there's one line at the top of each
comamnd that initializes things, and possibly a line at the bottom to
close those things down. Turn those lines into a context manager, which
is actually a sub-framework inside Typer. Don't convolute/compilicate
your design to eliminate one line at the top of each command.

Go ahead, accuse me of writing FORTRAN (all caps, no numbers or
qualifiers, as $deity intended) in Python. But neither optimize
prematurely nor invoke the Inner Platform Effect to save one or two
lines in your not-yet-written commands, either.

Sorry for the rant. :-)

Simple is better than complex.
Complex is better than complicated.

HTH.

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