[GiNaC-list] Parse error involving factorial symbol

Vladimir V. Kisil V.Kisil at leeds.ac.uk
Fri May 14 15:33:35 CEST 2021

>>>>> On Fri, 14 May 2021 15:08:09 +0200, Roberto Bagnara <bagnara at cs.unipr.it> said:

    RB> On 5/14/21 9:52 AM, Vladimir V. Kisil wrote:
    >> Dear Roberto!  It seems that Ginsh and parser in GiNaC are
    >> implemented differently. Ginsh understands postfix factorial
    >> notation like "3!"  but GiNaC parser is not. GiNaC parser is
    >> still happy with "factorial(3)".  Best wishes, Vladimir

    RB> Thanks Vladimir!  But please help me understand: I did not
    RB> change anything in the part of the code invoking the GiNaC
    RB> parser, and I did not change the tests.  So the situation you
    RB> are describing, i.e., GiNaC parser not understanding postfix
    RB> factorial notation, is something that changed from, say, 10
    RB> years ago.  In other words, do you agree that, say, 10 years
    RB> ago, the GiNaC parser was accepting that notation?

    It seems that before 2008-08-21 GiNaC and Ginsh had used the same
  parser, which Ginsh is using till now. After a patch they diverged in
  this respect. So it is quite well possible that your code was running
  with the old version of GiNaC but cannot do this now without some alteration.
Vladimir V. Kisil                 http://www.maths.leeds.ac.uk/~kisilv/
  Book:      Geometry of Mobius Maps       https://doi.org/10.1142/p835
  Soft:      Geometry of cycles         http://moebinv.sourceforge.net/
  Jupyter notebooks:       https://github.com/vvkisil/MoebInv-notebooks

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