On Sun, 3 Sept 2023 at 21:08, Aaron Meurer <asmeu...@gmail.com> wrote: > > On Sun, Sep 3, 2023 at 11:43 AM emanuel.c...@gmail.com > <emanuel.charpent...@gmail.com> wrote: > > > > I wonder if this problem could be handled with a auto_evaluate context > > handler, signalling to the symbolic expression system that the automatic > > evaluation is not allowed at this stage. Of course, you should have a tool > > to evaluate unevaluated expression (analogous to thehold/unhold mechanism > > available in large parts of Sage or the quoting/nouns mechanism > > (contraption…) of Maxima)… > > SymPy already has an evaluate(False) context manager. But that doesn't > really solve the fundamental problem, which is that virtually every > algorithm in SymPy is written expecting evaluation. If you search the > issue tracker, you'll find hundreds of issues with various things that > don't work when you disable evaluation.
See also "Deprecating evaluate(False): https://github.com/sympy/sympy/issues/25618 And also "Expression builder pattern": https://github.com/sympy/sympy/issues/25620 Other computer algebra systems that have automatic evaluation and things like hold/unhold also have many problems similar to SymPy's problems with it. The solution is not complicated: just have an unevaluating expression type and use it everywhere internally. Explicit evaluation is easy: just add an .evaluate() method to the unevaluating expression type. All internal code could then be changed to use unevaluating expressions easily. The tricky part is that many users will still want to use expressions that have automatic evaluation but some would definitely want the non-evaluating expressions. We need a UI for handling multiple expression types that is not confusing. Many users are already confused about the distinction between Python types like int and SymPy types like Integer and then also things like NumPy arrays etc so adding multiple types of SymPy expression risks confounding that. -- Oscar -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/CAHVvXxQFPsNbA0XMRdqTxOU9iA4KfDKabd3wWEG7H_yz48zybQ%40mail.gmail.com.
