Loris Bennett <loris.benn...@fu-berlin.de> ezt írta (időpont: 2021. aug. 20., P 17:54):
> Julio Di Egidio <ju...@diegidio.name> writes: > > > On Friday, 20 August 2021 at 11:54:00 UTC+2, Loris Bennett wrote: > >> Hi, > >> > >> TL;DR: > >> > >> If I have a command-line argument for a program, what is the best way > >> of making this available to a deeply-nested[1] function call without > >> passing the parameter through every intermediate function? > > > > To not pass arguments you need shared state ("global variables"): and > > options in shard state, unless you have very good reasons to do > > otherwise, is simply a no no. > > Doesn't that slightly depend on the size of your "globe"? If a program > does a few, in some sense unrelated things, and, say, only runs for a > few minutes, could you not decide to make a particular parameter global, > even though only one function needs it? In general, however, I would > also avoid this. > > > <snip> > >> I can see that the top-level could just create an object from a class > >> which encapsulates everything, but what if I want to keep the salutation > >> generation separate, so that I can have a separate program which just > >> generates the salutation and print it to the terminal? > > > > Yes, that's basically the way to go: parse arguments into a structure (an > > object) that contains all options/parameters then pass that down. Next > level: > > some sections of your code may require a certain subset of those > options, some > > may require some other, so you would structure your options object in > > sub-objects for the various sets of correlated options, then rather pass > just > > the sub-object(s) that are relevant to the section of code you are > calling. > > Variations are of course possible, anyway that's the basic idea. > > > > Also have a look at the "argparse" library, it does all the heavy > lifting for > > the parsing and creation of those objects, definitely advised for in non > trivial > > cases: <https://docs.python.org/3/library/argparse.html>. > > I am already using 'argparse' ('configargparse' actually). What aspect > should I be looking at in order to produce "sub-objects"? > > >> I guess I am really asking how to avoid "passing through" arguments to > >> functions which only need them to call other functions, so maybe the > >> answer is just to avoid nesting. > > > > No, you don't get rid of code structure just not to pass arguments to > > a function... Code may be poorly structured, but that's another > > story. > > As I am writing new code it is more a question of imposing structure, > rather than getting rid of structure. Unwritten code for a given > purpose obviously has some sort of structure with regards to, say, loops > and conditions, but I am less sure about the implications for how the > code should be nested. Another argument against deeply-nested functions > is the increased complexity of testing. > > Cheers, > > Loris > > -- > This signature is currently under construction. > -- > https://mail.python.org/mailman/listinfo/python-list > > > > Hi, Also you can give a try to click and / or typer packages. Putting args into environment variables can be a solution too All of these depends on several things: personal preferences, colleagues / firm standards, the program, readability, variable accessibility (IDE support, auto completition) (env vars not supported by IDEs as they are not part of code) BR, George -- https://mail.python.org/mailman/listinfo/python-list