RE: comments on XSLT draft 13 August 1999

[Kay Michael <Michael.Kay@xxxxxxx>]

> 10) 11.4 Top-level Variables and Parameters
> 	Why not use the same visibility rules for top-level 
> variables and parameters as for template variables and parameters: they
are 
> visible in following siblings and their descendents?  Forcing XSLT
processors to
> handle forward references to other top-level variables and 
> parameters adds complexity without any functional benefit.  Since circular

> references are prohibited anyway, there must be some ordering that
eliminates forward
> references, so why not just prohibit forward references?
> 
I agree strongly with this. The current ordering rules give me considerable
problems.

I have previously raised the comment (which is not addressed in the current
draft) that the current rules don't handle other forms of circular
reference, e.g.

<variable name="index">
    <apply-templates select="//record[last()]"/>
</variable>
<template match="record[number($index)]" priority="2">1</template>
<template match="record">2</xsl:template>

The simplest answer to this one is to ban calls on apply-templates and
call-template within a global variable declaration.

Circular references can also be caused by key definitions (a global variable
uses a key, while the key definition uses the global variable) and by named
attribute sets. A general principle of "no forwards references" could solve
many of the problems at a stroke.

Mike Kay


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