Re: Alternative algorithm to restrict use of data/string in patterns.

[Kohsuke KAWAGUCHI <kohsuke.kawaguchi@eng.sun.com>]

> > If calcFPDS can be made to the unary function, then what will be 
> > calcFPDS(<attribute/>) and calcFPDS(<empty/>)?
> 
> I think you would return "element",  since "element"|X = X for any X.

I still think calcFPDS cannot be an unary function.

Consider checking the following pattern (with calcFPDS', which is the
unary version of calcFPDS)

<oneOrMore>
  <group id="g1">
    <string>abc</string>
    <group id="g2">
      <element />
      <group id="g3">
        <string>def</string>
        <empty />
      </group>
    </group>
  </group>
</oneOrMore>



check( <oneOrMore> ....... </oneOrMore>, "element" )

=> check( <group id=g1> ... </group>,
       calcFPDS'( <oneOrMore>...</oneOrMore> )

=> check( <group id=g1> ... </group>, "text" )

=> check( <group id=g2> <element/> <group id=g3/> </group>, "text" )
 & check( <string>abc</string>, calcFPDS( <group id=g2 /> ) )

   consider the first check

=> check( <group id=g3> <string/> <empty/> </group>, "text" )
 & check( <element/>, calcFPDS(<group id=g3 />) )

   again consider the first one

=> check( <empty/>, "text")
 & check( <string>def</string>, calcFPDS(<empty/>) )

  consider the second check.
  According to your suggestion, calcFPDS(<empty/>) is "element".

=> check( <string>def</string>, "element" )
=> OK

  So it can't detect that the pattern is illegal. However, the pattern
is actually illegal because it is equivalent to

<oneOrMore>
  <string>abc</string>
  <element />
  <string>def</string>
</oneOrMore>



--
Kohsuke KAWAGUCHI                          +1 650 786 0721
Sun Microsystems                   kohsuke.kawaguchi@eng.sun.com