[GAP Forum] Indeterminates

[Asst. Prof. Dmitrii (Dima) Pasechnik]

Dear Mattew,
IsBound(q) would do just what you need.
Best,
Dmitrii

2009/7/31 Matthew Fayers <m.fayers at qmul.ac.uk>:
> Dear forum,
>
> I have a custom package containing lots of functions that I use frequently, that I usually read into GAP at the start of every session.  Since I frequently use polynomials in one variable, one of the first lines of this package is
>
> q:=Indeterminate(Rationals,"q");
>
> The trouble is, if I modify the package and then re-read it into the session, GAP reads the line above again and assigns two indeterminates, both called q.  This causes problems for functions that refer to q.
>
> Is there a way around this, apart from closing a re-opening GAP every time I update my package?  For example, is there a way to modify the above line so that it says something like "if q is not already assigned, let it be an indeterminate"?
>
> Matt.
>
> _____________________________________________________________________________________________
> Matthew Fayers
> School of Mathematical Sciences
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