Hyphens vs underscores in element names

Peter Murray-Rust peter at ursus.demon.co.uk
Wed Jan 26 08:40:39 GMT 2000

At 06:26 PM 1/26/00 +1300, Warren Hedley wrote:
>Hello XML-DEV


>One of the more popular arguments between the development team for
>FieldML regards a convention for the naming of elements and
>attributes in our ML collection. The debate focuses over whether
>we should use underscores (num_elements), hyphens (num-elements),
>capitalisation (numElements) or runtogether (numelements). We've
>eliminated capitalisation and runtogether because they don't
>look as nice, and are now reduced to hyphens vs. underscores. The
>older part of the development team is familiar with Fortran and C
>and are keen to use underscores. However I've noticed in a brief
>survey (results below) that most of the W3C-endorsed stuff seems
>to feature minus signs.
>Can anyone suggest any compelling reasons for going either way?
>Does anyone want to add more data to my survey?

In scientific/technical areas it is highly likely that you are going to
need to write code for at least some of your elements, especially if they
relate to numeric or other non-textual data. In this case it is natural to
name the classes/variables in a way that reflects the XML names. If you
include punctuation which is reserved in the implementation language you
may hit problems. '-' and '.' are particularly common. For example, we
discovered to our disappointment that our domain name (xml-cml.org) could
not be used as a package name in Java, i.e.:
package org.xml-cml;
cannot contain a '-'

In naming elements in CML (Chemical Markup Language)
[http://www.xml-cml.org] I tried to avoidconcatenatedwords, but did it for
some attribute values
  <string builtin="atomRef">a1</string>
  <string builtin="atomRef">a2</string>      
[We may move to an alternative representation later (e.g.

In writing DOM-based code I have things like:
public class BondImpl extends CMLBase implements Bond {...}
If anything in those names is reserved punctuation you have to modify the


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