Forwards-compatible syntax proposal

Nathan de Vries nathan at
Mon May 26 06:37:07 PDT 2008

On 13/05/2008, at 10:07 AM, Ian Hickson wrote:
> CSS and HTML already have the feature that they are resilient to  
> new syntax, I think the forward compatibility this offers is far  
> more valuable than the "draconian" error handling in JS today.

I'm not entirely sure that comparing the ease of forwards- 
compatibility of ES to CSS/HTML is fair. The side effect of dropping  
foreign declarations in CSS/HTML is negligible, unlike that of  
dropping entire blocks of foreign code in ES. The migration from XSLT  
1.0 to 2.0 is a much more realistic comparison.

On a slightly related note, one of the options available to those  
migrating XSLT 1.0 stylesheets to XSLT 2.0 (other than a full re- 
write) was to convert the stylesheets to 2.0 but re-use the 1.0  
islands. Is this kind of code re-use going to be possible with ES4?  
i.e. Can a chunk of ES4 defined in a <script type="application/ 
javascript;version=2" /> block interact with ES3 code defined in a  
<script type="application/javascript" /> block? Has this behaviour  
been decided on?


Nathan de Vries

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