Re: Error S06

The specification treats three classes of error:
 - syntactic errors, where the input doesn't match the grammar; 
 - static errors, where the input matches the grammar, but doesn't adhere to certain requirements which can be checked by inspection (such as the from part of a range being greater than the to part), and 
  - dynamic errors, that can only be discovered at runtime.

The only requirement of an implementation is that it performs as specified, so if it chooses to use a different grammar, and treat some syntax errors as static errors, that is fine as long as it adheres to the specification, but it is not the aim of the specification to anticipate every way an implementation may process the language.

So from the point of the view of the specification, it is not even possible to have a hex value that contains non-hex characters, so we don't have to allocate an error to it. If we did, then it would open a can of worms about all the different ways an implementation might work. As long as the specification is coherent, all is well.

Best wishes,

Steven 

On Tuesday 03 February 2026 22:05:34 (+01:00), Gunther Rademacher wrote:

> Steven Pemberton wrote:
> > While updating the Unicode conformance text, I removed these three errors 
> > that cannot occur.
> 
> Steven,
> 
> your change seems to assume that ixml is necessarily used to parse the input grammar. To the best of my knowledge, that is not prescribed by the spec. For example, Markup Blitz uses REx to parse its input grammar, and some of these error codes can also occur when the input grammar is presented in XML.
> 
> S01 is generated by Markup Blitz, as expected by this test case:
> 
>     https://github.com/invisibleXML/ixml/blob/ca938ecd62970366dc60845a8549cc2f63c18694/tests/syntax/catalog-as-grammar-tests.xml#L299-L305
>     
> S06 is generated by Markup Blitz, as expected by this test case:
>     
>     https://github.com/invisibleXML/ixml/blob/ca938ecd62970366dc60845a8549cc2f63c18694/tests/syntax/catalog-as-grammar-tests.xml#L379-L385
> 
> S11 is generated by Markup Blitz, as expected by this test cases:
> 
>     https://github.com/invisibleXML/ixml/blob/ca938ecd62970366dc60845a8549cc2f63c18694/tests/syntax/catalog-as-grammar-tests.xml#L387-L393
>     https://github.com/invisibleXML/ixml/blob/ca938ecd62970366dc60845a8549cc2f63c18694/tests/syntax/catalog-as-grammar-tests.xml#L395-L401
> 
> It also occurs for the following XML input:
> 
>     <ixml><rule name="S"><alt><literal string="&#xA;"/></alt></rule></ixml>
> 
> Given this, I’d vote for just keeping these error codes.
> 
> Best regards
> Gunther
>

Received on Wednesday, 4 February 2026 14:49:39 UTC