Pointless <sequence>, <choice>, <all>

Hello,

I find the text describing "pointless" particles (3.9.6 Constraints on
Particle Schema Components - Schema Component Constraint: Particle Valid
(Restriction)) a bit unclear.

The first question I have is why does the text mixes XML Element
Information Items and Schema Components?

For example what is "The <sequence>'s {particles}"?

Or what is a <all> whose {particles} is empty?  If an <all> with no
<element> child is used within a <complexType>, isn't it supposed to
mean that the content type of the complex type is empty?  If so is these
a particle created for that <all> that could justify the reference to
the {particles} property?

Second question: is the sequence in the following complex type pointless?

<complexType>
  <sequence>
    <element name="e"/>
  </sequence>
</complexType>

If yes, how could the following condition be verified?

2.2.2.1 The particle within which this <sequence> appears has {max
occurs} and {min occurs} of 1.

If no, does the following <complexType> express a valid complex type
definition?

<complexType>
  <complexContent>
    <restriction base="anyType">
      <all>
        <element name="e"/>
      </all>
    </restriction>
  </complexContent>
</complexType>

Thanks,

Michael Marchegay

Received on Thursday, 23 October 2003 09:48:16 UTC