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Re: Build Rich Complexity from a Small Set ofWell-Defined Mark

• From: John Cowan <cowan@mercury.ccil.org>
• To: "Costello, Roger L." <costello@mitre.org>
• Date: Wed, 24 Aug 2011 11:42:20 -0400

Costello, Roger L. scripsit:

> Interestingly, XML Schemas is considered to be a complicated
> language. Perhaps 7 markup combinators are too many in a markup
> language?

What makes XSD complicated is the irregularity of the rules.  For example,
a choice between child elements is representable, but a choice between
attributes is not.  What is more, there are many special rules about
what can and cannot be done, the Unique Particle Attribution rule being
the most notorious.

By comparison, RELAX NG has 9 basic patterns (element, attribute,
reference, parent reference, empty, text, datatype, typed value,
notAllowed) and 8 combinator patterns (sequence, interleave, choice,
optional, zeroOrMore, oneOrMore, list, mixed), but feels much simpler
than XSD because of the relatively few restrictions in combining them.

> From that will flow complexity of great richness.

And that's just what RNG provides.

-- 
When I'm stuck in something boring              John Cowan
where reading would be impossible or            (who loves Asimov too)
rude, I often set up math problems for          cowan@ccil.org
myself and solve them as a way to pass          http://www.ccil.org/~cowan
the time.      --John Jenkins

• Follow-Ups:
  • Re: Build Rich Complexity from a Small Set of Well-Defined MarkupCombinators
    • From: Richard Salz <rsalz@us.ibm.com>

• References:
  • Build Rich Complexity from a Small Set of Well-Defined MarkupCombinators
    • From: "Costello, Roger L." <costello@mitre.org>