Claudiu, Peter

Does anyone of you know why lib2to3 is using both a bottom-up parser and
pgen2? It "looks" like there are two parsers. I'm quite confused by the
parser design of lib2to3, because in older versions (python 2.6) there's
only pgen2.

~ Dave

2014-09-29 19:15 GMT+02:00 Claudiu Popa <pcmantic...@gmail.com>:

> On Mon, Sep 29, 2014 at 1:02 PM, Dave Halter <davidhalte...@gmail.com>
> wrote:
> > Hi all!
> >
> > I will be writing a new parser for Jedi. This is necessary for a quite a
> few
> > reasons described in:
> > https://github.com/davidhalter/jedi/issues/480.
> >
> > I'm posting this here, because some of you may be interested in actually
> > using the new parser. It's going to be pure Python and contrary to the
> > Python's internal parser will have error recovery and indent positions.
> >
> > If you're interested, I'd be really glad to hear your feedback!
> >
> > ~ Dave
> >
>
>
> Hello, Dave.
>
> That's awesome, If your parser can generate a new AST, then we can
> definitely use it, although we have
> in mind to use lib2to3 to replace the standard ast module for our use
> cases, but that can change if your parser
> is finished until taking action from our side. Having always correct
> information, such as line and col offsets definitely will
> help us (we actually have a couple of problems regarding this, where
> the lineno for some nodes is different than reality).
> Regarding the parser approach, I'm not sure what's best in this situation.
> I'm working on a static analysis tool, in the vein of pylint, for the
> Powershell language
> (https://github.com/RoPython/wispy) where I'm using modgrammar, a
> recursive descent top down parser to parse the code
> and retrieve an AST from it. modgrammar is pretty good, easy to use,
> but slow sometimes and backtracks too much on ambiguities.
> But it can memorize whitespace tokens and such, as long as you
> explicitly define the whitespace token in the grammar, which
> can be a pretty daunting task.
>
> Anyway, if there is something I can help you with your parser, don't
> hesitate to send me an email.
>
>
> Claudiu
>
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