dent at oofile.com.au
Mon Jun 28 23:07:45 BST 1999
At 17:17 -0400 27/6/99, Paul Prescod wrote:
>Although I am in favor of instance syntax in general I think that
>recasting regular expressions as nested elements is a big mistake from a
>usability point of view and a very small gain from an ease-of-parsing
>point of view.
I'm really not sure I understand what you're talking about here so
the following comments may be totally inapplicable, but I think my
point below is still valid.
From a usability point of view (which drives a LOT of my API design)
I think it is much easier for most people to understand definitions
Many document types, and particularly database documents, will define
elements that are only meaningful in a larger context (eg: LastName
The X-schema and DTD modes seem to support only defining all atomic
elements separately from a context saying where they are used.
This requires the reader and writer of these schemae to build an
abstract model in their heads that puts the definitions in context.
For both machine and human reading and writing of schemae, where
nested contexts are meaningful, I found the following variation much
easier to follow.
So did the programmers I tested it on - as a UI designer of several
years experience I'm not so bold as to propose something on usability
grounds without a focus group :-). The test group I picked range in
programming experience, database experience and programming
languages(VB, C & C++). The only common factor was their lack of XML
or SGML background.
The contextual definition of elementTypes which are atomic
(containing a dataTypeRef) also allows for reuse of element names
which is essential for writing out database schemae.
<datatypeRef name='string' length='25'/>
<datatypeRef name='string' length='15'/>
Andy Dent BSc MACS AACM, Software Designer, A.D. Software, Western Australia
OOFILE - Database, Reports, Graphs, GUI for c++ on Mac, Unix & Windows
PP2MFC - PowerPlant->MFC portability
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