[GiNaC-list] ginsh as a subroutine?
J.P.Fletcher at aston.ac.uk
Thu Jun 23 15:08:12 CEST 2005
Date sent: Wed, 22 Jun 2005 23:45:19 +0200 (CEST)
From: "Richard B. Kreckel" <kreckel at ginac.de>
To: GiNaC discussion list <ginac-list at ginac.de>
Subject: Re: [GiNaC-list] ginsh as a subroutine?
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> On Wed, 22 Jun 2005, John Fletcher wrote:
> > I would like to be able to call a subroutine with a string e.g.
> > "x+y"
> > and receive back an ex object containing the expression and also a
> > map mapping "x" and "y" strings to symbol objects.
> Well, ex::construct_from_string_and_lst(const string&, const ex&)
> expects you to provide the list of symbols.
That one aborts if the symbol is not in the list.
I would prefer one which adds the missing symbols, and think that
is best done as a map as there are not duplicate symbols with the
same name. For example, if I process
x = 1;
it will make a symbol "x" with a key of "x" and if I then process
y = x + 2;
with the same map it will add "y" in the same way. I can always
extract the symbols and also the names and e.g. make a list.
> > The example program ginsh does this internally. I think it could be
> > added within the class for ex objects. Has anyone done this?
> That sounds like a promising project. If it could parse strings like
> "expand((x+y)^2)", then this would be eminently useful for creating a
> decent interface for TeXmacs. There are a number of alternatives how
> to interface TeXmacs, but I'm under the impression that the cleanest
> way is via a string parser right inside the library, as opposed to the
> one in ginsh or yet another one outside GiNaC proper.
> Richard B. Kreckel
> GiNaC-list mailing list
> GiNaC-list at ginac.de
I take it then that this hasn't been done.
Thanks for the comments
Dr John P. Fletcher Tel: (44) 121 204 3389 (direct line)
Chemical Engineering and Applied Chemistry (CEAC),
School of Engineering and Applied Science (SEAS),
Aston University, Aston Triangle, BIRMINGHAM B4 7ET U.K.
CEAC Web site http://www.ceac.aston.ac.uk/
FAX: (44) 121 204 3679
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