Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!munnari.oz.au!goanna!ok
From: ok@goanna.oz.au (Richard O'keefe)
Newsgroups: comp.lang.eiffel
Subject: Re: Comments on proposed Eiffel language changes
Message-ID: <2888@goanna.oz.au>
Date: 20 Feb 90 07:34:10 GMT
References: <48a55876.12c9a@digital.sps.mot.com>
Organization: Comp Sci, RMIT, Melbourne, Australia
Lines: 35

In article <48a55876.12c9a@digital.sps.mot.com>, shelley@atc.sps.mot.com (Norman K. Shelley) writes:
> Page 240 of "Eiffel: The Language" states that "internal upper-case letters ...
> as in putAtRight, contradicts the standard conventions of English ...
> and is not  part of the recommended style."  I agree BUT must note that the
> underscore ('_')
> as a word separator is NOT English either.  A whitespace is the accepted
> standard but computers have troubles with whitespace in names/labels so what do
> we do?

This is contrary to fact.  Computers have no trouble whatsoever with
layout inside names.  Consider Fortran, Algol 68, and IMP for starters.
I also have a modified Prolog which allows layout inside names as well,
where I adopted the rule that 1 or more layout characters inside an
identifier were equivalent to a single underscore, so that
	translation of identifier(New Style Identifier, Old Style Id)
was read the way that
	translation_of_identifier(New_Style_Identifier, Old_Style_Id)
is read in normal Prolog syntax, so this could coexist with a standard
tokeniser/parser.

The only thing that tokenisers have trouble with is telling where one
identifier ends and another begins.  There are several ways around this.
One of them is to use a syntax where the issue just doesn't arise.
For example,
	require latest x = old y;
would cause a problem, but if it were
	require (latest x = old(y));
so that identifier never met identifier, the problem would go away.
Another is to use a form of stropping; there were four official
methods of stropping for Algol 68 and IMP used another, e.g.
	%require latest x = %old y;

I _don't_ agree that the Eiffel lexical rules for identifiers warrant
changing, but let's but delude ourselves, the only reason for not allowing
spaces in identifiers is the language designer's careful choice.