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

Steven D'Aprano steve at pearwood.info
Tue Jul 1 19:15:29 CEST 2014


On Tue, Jul 01, 2014 at 09:58:37AM -0700, Nick Coghlan wrote:
> On 1 July 2014 01:27, Andrew Barnert <abarnert at yahoo.com> wrote:

> > But CPython does expose bytecode via the dis module, parts of 
> > inspect, etc. [...]
> 
> Note that the dis module has a "CPython implementation detail"
> disclaimer, and the AST structure is deliberately exempted from the
> usual backwards compatibility guarantees.

Further to what Nick says, the *output* of dis is not expected to remain 
backwards compatible from version to version, only the dis API itself.

There's a big difference between saying "we guarantee that the dis 
module will correctly and accurately disassemble valid bytecode", and 
saying "we guarantee that this specific chunk of bytecode will do these 
things". In order to use a hypothetical asm function, you need to know 
what pseudo-assembly to write, say `asm [SPAM, EGGS]`. That means that 
SPAM and EGGS must be stable and part of the language definition. (Or at 
least part of the CPython API.) That's a big step from the current 
situation.


-- 
Steven


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