On 2 November 2017 at 09:16, Lukasz Langa <lukasz@langa.pl> wrote:

I find this sad. In the JavaScript community the existence of Babel is very important for the long-term evolution of the language independently from the runtime. With Babel, JavaScript programmers can utilize new language syntax while being able to deploy on dated browsers. While there's always some experimentation, I doubt our community would abuse the new syntactic freedom that the PEP provided.

Then again, maybe we should do what Babel did, e.g. release a tool like it totally separately from the runtime.

Right, I think python-modernize and python-future provide a better model for Babel equivalents in Python than anything built directly into CPython would.

In many ways, python-future's pasteurize already *is* that kind of polyfill, where you get to write nice modern Python yourself, and then ask pasteurize to mess it up so it also works on Python 2.7: http://python-future.org/pasteurize.html

The piece that we're currently missing to make such workflows easier to manage is an equivalent of JavaScript's source maps (http://blog.teamtreehouse.com/introduction-source-maps), together with debugging tools that are able to use source map information to generate nice tracebacks, even when the original sources are unavailable.

Source maps could also potentially help with getting meaningful tracebacks in other contexts, like bytecode-only deployments and Cython extension modules (for example, the traceback problem is the main reason Red Hat's Python container images still have the source code in them - when that was last measured, you could get an image size reduction of around 15% by including only the pyc files and omitting the original sources, but it wasn't worth it when it came at the cost of making tracebacks unreadable).

Cheers,

Nick.

Nick Coghlan | ncoghlan@gmail.com | Brisbane, Australia