I think GP means `python3 -mvenv my_venv` rather than running in a VM or any heavyweight virtual environment. At least that's how I interpret 'virtual environment' in a pythonic context, and they're certainly lightweight enough.

What I took GGP to be talking about though was lightweight in terms of cognitive load. Like "can I just run the thing please!" aka yak shaving [0]

[0] https://seths.blog/2005/03/dont_shave_that/

In other comments you talk about "lightweight" as cognitive load, I'm curious why Python is any different than other languages?

I haven't used virtualenv very much, but I've been doing similar things for longer than virtualenv has been around. You need a `python` binary on PATH and a PYTHONPATH pointing to where you want to get your libraries from. virtualenv packages this up into a directory in a more user friendly fashion.

Most docs I've seen on Python2/3 advise on choosing one or the other, ideally 3. Which implies mixing should either be done very carefully or with a plan to transition to 3.

I get that some accidents of history have caused headaches. The deep adoption by distros have caused problems when people just want to use Python/libs installed with the OS (as well as moving to Python 3), authoring packages hasn't been great historically, etc.

That you needed four paragraphs to get your point across kind of emphasises my point.

I don't mean to be rude, but the key to getting people's attention is to get your point across quickly. As soon as somebody starts going all you have to do is install a frobozz and murtle a plinth I really just lose interest.

EDIT - doubting myself I went back up the thread here and this topic kicks off with "meson installation has many dependencies, it is not very lightweight" ("lightweight" operationally defined here for this discussion) - to which somebody replies "it doesn't matter, Ninja includes Python" or words to that effect. "it's not the correct version of Python" is the general gist of what comes next to which our GGP here says "all you have to do" is set up a python virtual environment, which is around the point where I start to feel frustrated and the need to go do something interesting.

So to be clear, the discussion is not about python being lightweight, but meson, and trying to wave complexity away with yet another layer of complexity (even if it's something as well known as python virtualenvs) is not reducing complexity but hiding it, IMO.

I honestly wasn't trying to be combative. I tried to make my comment just long enough to give context (showing my understanding of the solution and the assumptions I'm making). I'm not trying to interject my opinion, but see where my assumptions might be wrong.

I agree long wandering threads are difficult to follow.

I have little interest in new C++ build systems, but will jump in and contribute when I see a familiar problem I want to learn more about like managing sizable Python codebases. Python 2/3 isn't relevant at all to meson and I don't see the docs mentioning any need for version or package management. I've only ever heard/seen virtualenv needed in project management, never in distributed software. Is your beef with Python or any software using an interpreted language? Outside of the 2to3 transition and being deeply integrated in many distros, it has the fundamental problems other interpreted languages have and are handled in the same way.

It is if you run it inside a Docker container... no mess, no fuss...

I cant tell if you’re joking or not ;)

Depends if someone's already written the Dockerfile for you ;)

But to be fair, I usually just clone a Virtualbox machine because I'm used to the workflow. :)

Actually it is, but nevertheless that's only required by those who for some reason still believe today that python2 vs python3 is an issue.

I have python 2 vs 3 issues if not every day, then at least 3 times a week, because of being stuck with a version of third party software that uses Python 2 (ArcGIS 10 series) for part of my code base. Of course Python apologists are now going to say 'oh you're just one guy in a niche situation', and 'yeah that's what you get for not upgrading to the latest version of all software', or any of the dozens of other excuses and blame I get anytime I have to defend why I need to use Python 2. Fact is still that I'm bound by external constraints and that Python versioning is a real problem in my day to day work, and yes that is in 2019. Look, Python isn't much worse or better than most other languages in its niche, but please do away with the 'everything about Python is easy and great' spiel.

In fairness to the python community by-and-large, they are very supportive of legacy users and niche configurations. Python 2.x seems like something like 15 years now past its sell by date and is still actively supported. There's a lot of patience there ... people will make the leap when they're ready.

I think the pressure to always be on the latest and greatest is what did for the ruby and perl communities, and this is why python, and to a certain extent javascript are still going strong!

Not disagreeing with you, just clarifying: I'm not even complaining so much about the Python 'development' community (i.e., those writing the interpreter and most of the people writing libraries); what irks me is the 'evangelists', Python users who feel the need to proselytize about things that are obviously not perfect, but claim they are and straight up dismiss any objections or real world concerns. I'm talking about the people who with a straight face call themselves 'Pythonistas'. Jebus, if so much of your self image and self worth is tied up in the programming language you like to use most, you need professional help. Of course all languages have people like this, and most 'communities' that are not software related have similar people too, it's just that posts like this seem to bring out this sort of hanger-ons. It probably also has something to do with me turning into Statler or Waldorf over time. Meh.

There are a few different meanings of the word lightweight, and I get a sense you're not using the one that I or GP are using.