[Om] Accessing arguments of an n-ary operator as indexed list items (in a definition)

Professor James Davenport jhd at cs.bath.ac.uk
Sat May 9 19:27:21 CEST 2009

On Sat, May 9, 2009 3:12 pm, Christoph LANGE wrote:
> On Saturday 09 May 2009 15:31:46 Professor James Davenport wrote:
>> What I meant is that you say "assuming the existence of such a function
>> x(i) ...". I've always assumed we meant list_selector from list2, but we
>> haven't made that as clear as we should.
>> Incidentally, I've noticed a missing FMP there: will fix.
> I see!  Well, I hadn't even been aware of the list2#list_selector symbol
> when
> writing my previous mails.  I had mentioned list3#entry, though, which
> seems
> redundant with the former.  (So shouldn't we actually deprecate one of
> them
> and declare it equivalent with the other one? -- Do you want me to file a
> ticket on that?)
Unfortunately, ist3#entry (which I wasn't aware of - so we're quits) does
the "counting backwards for negative arguments" trick, which I personally
hate (it complicates the implementation, and allows bugs to drift on for
the unwary - if I WANT to count backwards I know it).  Please do raise a
ticket, though, as I'd like to know what others think.

James Davenport
Visiting Full Professor, University of Waterloo
Hebron & Medlock Professor of Information Technology and
Chairman, Powerful Computing WP, University of Bath
OpenMath Content Dictionary Editor and Programme Chair, OpenMath 2009
IMU Committee on Electronic Information and Communication

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