Thank you very much!
On Tuesday, August 13, 2024 at 1:09:29 AM UTC+3 asme...@gmail.com wrote:
> You need to write a function that takes the stream of tokens and
> returns a new stream of tokens which are re-parenthesized. For
> example, ['p', '>>', 'q', '>>', 'r'] would become ['p', '>>', '(',
> 'q', '>>', 'r', ')']. But you'd also need to handle the case where one
> of the operands is itself parenthesized or involves operators with a
> higher precedence than >>.
>
> Unfortunately, this isn't the simplest thing in the world to do. It
> would probably be useful to add something to SymPy that lets you take
> a general transformer that can adjust operator precedence and
> associative rules. Or we should write our own custom parser for
> parse_expr that makes it easier to make these sorts of changes (both
> of these are things we would like to see, but not easy tasks).
>
> Here are examples of existing token transformers for parse_expr
> https://github.com/sympy/sympy/blob/master/sympy/parsing/sympy_parser.py.
> My guide to the Python tokenizer module can also be useful
> https://www.asmeurer.com/brown-water-python/
>
> Aaron Meurer
>
>
> Aaron Meurer
>
> On Mon, Aug 12, 2024 at 1:46 PM Paul Royik <distan...@gmail.com> wrote:
> >
> > Thank you.
> >
> > Can you point me how it could look like?
> >
> > Thank you.
> >
> > On Monday, August 12, 2024 at 10:20:25 PM UTC+3 asme...@gmail.com wrote:
> >>
> >> There's no way to change the Python operator precedence, but you can
> >> modify the string parsing in parse_expr() by passing in a transformer
> >> for the tokenizer.
> >>
> >> Aaron Meurer
> >>
> >> On Mon, Aug 12, 2024 at 12:38 PM Paul Royik <distan...@gmail.com>
> wrote:
> >> >
> >> > Hello.
> >> >
> >> > I'm trying to parse the ">>" symbol as implies operator.
> >> >
> >> > I've managed to parse p>>q>>r as Implies(Implies(p,q), r) using sympy
> functions as a base (possibly, there is a built-in solution that I'm not
> aware of), but it appeares that Implies is a right-associative operator.
> >> >
> >> > Are there some functions in Sympy that allow me to parse p>>q>>r as
> Implies(p, Implies(q,r))?
> >> >
> >> > Thank you.
> >> >
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