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[Python-ideas] .pyu nicode syntax symbols (was Re: Empty set, Empty dict)

Nick Coghlan ncoghlan at gmail.com
Tue Jul 1 18:58:37 CEST 2014 
On 1 July 2014 01:27, Andrew Barnert <abarnert at yahoo.com> wrote:
> (Replies to both Guido's top-post and Nick's reply-post below.)
>
> On Monday, June 30, 2014 7:19 PM, Guido van Rossum <guido at python.org> wrote:
>
>>Like bytecode, the compiler's workings are not part of the language spec, and are likely to change incompatibly between versions and not work for anything besides CPython. I don't really want to go there (cool though it sounds for wannabe compiler hackers).
>
>
> But CPython does expose bytecode via the dis module, parts of inspect, etc. For that matter, it exposes some of the compiler's workings (especially if you consider everything up to AST generation part of the compiler, since every step up to there is exposed, including doing the whole thing in one whack with PyCF_ONLY_AST). So, I don't see how exposing the AST-to-bytecode transformation part (or, while we're at it, the .pyc generation part) is any more unportable than what's already there.
>

Note that the dis module has a "CPython implementation detail"
disclaimer, and the AST structure is deliberately exempted from the
usual backwards compatibility guarantees.

As far as hooking compilation goes,
https://docs.python.org/3/library/importlib.html#importlib.abc.InspectLoader.source_to_code
was added in 3.4 specifically to make it easier to define custom
loaders that make use of most of the existing import machinery
(including bytecode cache files), but do something different for the
source -> bytecode transformation step.

Cheers,
Nick.
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