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RE: questionable syntax choices for XQuery

From: Michael Kay <mhk@mhk.me.uk>
Date: Thu, 22 Apr 2004 10:12:56 +0100
To: "'Xavier Franc'" <xfranc@online.fr>, <www-ql@w3.org>
Message-Id: <20040422091643.8D9F2A1D9F@frink.w3.org>

> 
> Some personal remarks about the semicolon separator between 
> declarations:
> 
> - it has been added silently in November (not listed in change list)
>   that's not nice for implementers...
> 
> - I have never understood the necessity of this change.
>   Is there some subtle lexical issue that I dont see ?

The syntax can be parsed without it, but it's very hard to produce decent
error messages and to recover from syntax errors without it. 

> 
>   actually this separator is optional in my own implementation
>   and I never noticed any parsing problem.
> 
> - I agree with Jason that making parser writing easier
>   is not a good justification for such a change.

But allowing better error messages and error recovery is a good
justification. The XQuery syntax is very fragile from this point of view
(because of the lack of redundancy), and the semicolon adds much-needed
robustness.

Michael Kay
Received on Thursday, 22 April 2004 05:16:43 GMT

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