[GiNaC-list] Parse error involving factorial symbol

Vladimir V. Kisil V.Kisil at leeds.ac.uk
Fri May 14 09:52:42 CEST 2021

```	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 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
>>>>> On Thu, 13 May 2021 22:47:59 +0200, Roberto Bagnara <bagnara at cs.unipr.it> said:

RB> Hi there.

RB> I am reviving some 10-years old software that is based on GiNaC.
RB> When I started the work I was pessimistic, given so much time
RB> has passed.  But now the thing compiles again.  The problem is
RB> that I cannot parse the test-suite that was used for validation.
RB> I get:

RB> on line 392: parse error: GiNaC: parse error at line 0, column
RB> 0: expected ')' or ',' in argument list, got: "!"  [GiNaC::ex
RB> GiNaC::parser::parse_identifier_expr()(parser/parser.cpp:88)]

RB> I guess something has changed in the parser, or maybe my
RB> reviving effort introduced a bug.  Line 392 is the last one in
RB> this block:

RB> y (n+3)!  factorial(3+n) factorial(3+n)
RB> factorial(n)*(3+n)*(1+n)*(2+n) factorial(3+n) factorial(3+n)

RB> This is the first block that contains an "!".  This and all the
RB> subsequent blocks of tests that contain an "!" symbol fail in
RB> the same way.  None of the blocks before fails.  Any hint?
RB> Thanks,

RB>    Roberto

RB> -- Prof. Roberto Bagnara Applied Formal Methods Laboratory
RB> Department of Mathematical, Physical and Computer Sciences
RB> University of Parma, Italy http://www.cs.unipr.it/~bagnara/
RB> mailto:bagnara at cs.unipr.it
RB> _______________________________________________ GiNaC-list
RB> mailing list GiNaC-list at ginac.de
RB> https://www.ginac.de/mailman/listinfo/ginac-list
```