Re: User definable operators

"Dr A. N. Walker" <anw@maths.nottingham.ac.uk>
3 Jan 1997 23:08:56 -0500

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[15 earlier articles]
Re: User definable operators mfinney@inmind.com (1996-12-26)
Re: User definable operators leichter@smarts.com (Jerry Leichter) (1996-12-27)
Re: User definable operators genew@mindlink.bc.ca (1996-12-28)
Re: User definable operators WStreett@shell.monmouth.com (1996-12-29)
Re: User definable operators adrian@dcs.rhbnc.ac.uk (1997-01-02)
Re: User definable operators hrubin@stat.purdue.edu (1997-01-02)
Re: User definable operators anw@maths.nottingham.ac.uk (Dr A. N. Walker) (1997-01-03)
Re: User definable operators WStreett@shell.monmouth.com (1997-01-03)
Re: User definable operators apardon@rc4.vub.ac.be (1997-01-07)
Re: User definable operators icedancer@ibm.net (1997-01-07)
Re: User definable operators wclodius@lanl.gov (William Clodius) (1997-01-09)
| List of all articles for this month |
From: "Dr A. N. Walker" <anw@maths.nottingham.ac.uk>
Newsgroups: comp.compilers
Date: 3 Jan 1997 23:08:56 -0500
Organization: Department of Mathematics, The University, Nottingham, UK
References: 96-12-088 96-12-110 96-12-147 96-12-163
Keywords: syntax, design, comment

Herman Rubin wrote:
> This particular ambiguity is typically blocked in most computer
> languages anyhow. In any of them, using xy for the product of x and y
> is prohibited, and I know of none for which even 2x is allowed.


                Atlas Autocode -- a Fortran-ish dialect of Algol of 1960-odd
-- allowed "2x", and "x.y" and "x'y'". The Flexowriters of that time
also had "half", "superscript 2" and "pi" symbols on the keyboard, so
that expressions like "half pi r-squared" could be written with a mere
four symbols, and looked in your program [or programme, as it was
called in those days] exactly like the same formula in pukka maths.
You could also create new symbols by overstriking [eg, "= BS /" to get
a "not-equal" symbol]. None of this caused any difficulty to the
compiler, which was in any case generated automatically by the
Brooker- Morris Compiler-Compiler.


                Isn't it amazing how far computer languages have advanced in
the last third of a century?


--
Andy Walker, Maths Dept., Nott'm Univ., UK.
anw@maths.nott.ac.uk
[Yeah, but I can't say I miss getting my coffee cup knocked onto the
floor every time the Flexowriter's carriage returned. -John]
--

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