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Re: Valid but Semantically Incorrect

From: Jon Ferraiolo <jferraio@Adobe.COM>
Date: Fri, 19 Nov 1999 09:18:19 -0800
Message-Id: <199911191715.JAA07363@mail-345.corp.Adobe.COM>
To: "Pankaj Kamthan" <kamthan@cs.concordia.ca>
Cc: www-svg@w3.org
Pankaj,
You are correct that the spec is currently ambiguous about what happens
when you provide incorrect values for certain parameters.

A new public draft of the SVG specification will be coming out soon with a
lot of cleanup and less ambiguity and which, in particular, is likely to
address the issue of what happens when a negative value is provided for a
radius.

One thing that should be pointed out. The W3C has an XML Schema effort
which will allow for more specific definitions of data constraints, such as
a particular value must be positive. However, XML Schema is on a schedule
after SVG, so until then the SVG specification will have to describe
constraints with descriptive text.

Jon Ferraiolo
SVG Editor
Adobe Systems Incorporated

At 08:53 AM 11/19/99 -0500, Pankaj Kamthan wrote:
>Hi,
>
>Consider the following example:
>
><?xml version="1.0"?>
><!DOCTYPE svg PUBLIC "-//W3C//DTD SVG August 1999//EN" 
>  "http://www.w3.org/Graphics/SVG/SVG-19990812.dtd">
><svg width="4in" height="3in">
>  <g><circle cx="200" cy="200" r="-100"/></g>
></svg>
>
>1. Wouldn't this be then a valid SVG document which is semantically
incorrect?
>2. Does the burden that the attributes take "sensible" values rest on a SVG
>conforming processor? 
>
>(This could be a generic problem: one can have an equation of a circle
with a 
>negative radius (so mathematically not possible) but can still come up
with a valid 
>MathML markup for it.)
>
>Somehow this wasn't clear from SVG Spec Chapters 7,11 and Appendix D. Any
>insight would be most useful.
>
>Thanks.
>Pankaj Kamthan
> 
Received on Friday, 19 November 1999 12:16:39 GMT

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