Issues with nearley on Python-3-only systems

[wiene]

I am trying to use lark on a Python-3-only system. During these tests I stumbled across the following issue: lark/tools/nearley.py depends on js2py and I am not able to make js2py work with Python 3 (I get a unit test failure, see PiotrDabkowski/Js2Py#185). The js2py author announced Python 3 support some time ago but the issue seems to persist.

Given the imminent end-of-life of Python 2 and the ongoing removal of Python 2 from Linux distributions (see e. g. the Debian plans and the Fedora schedule) what are your plans for dealing with the mentioned js2py dependence?

[erezsh]

From the js2py page:

Supports Python 2 & 3.

So you should hold them to their claim.

Given the imminent end-of-life of Python 2

Python2 will not stop being usable in the foreseeable future. It may not arrive on linux by default, but I'm guessing you can still apt install or yum install it for the next decade.

However, if you have a suggestion for a better replacement to js2py, I'm willing to consider it.

Either way, it won't affect Lark, as js2py is only an optional dependency and isn't required for anything but Nearley conversions, which honestly aren't too difficult to do by hand.

[wiene]

Python2 will not stop being usable in the foreseeable future. It may not arrive on linux by default, but I'm guessing you can still apt install or yum install it for the next decade.

Reading https://lists.debian.org/debian-python/2019/11/msg00038.html I am not so sure whether this will be the case but we will see.

However, if you have a suggestion for a better replacement to js2py, I'm willing to consider it.

Unfortunately I do not have a good suggestion. That is why I was asking.

Either way, it won't affect Lark, as js2py is only an optional dependency and isn't required for anything but Nearley conversions, which honestly aren't too difficult to do by hand.

Only now I realise that since the last release (0.7.8) the fact that this dependency is optional is also reflected in the test suite.