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Re: PHP code only allowed in XHTML 5?

From: Leif Halvard Silli <lhs@malform.no>
Date: Wed, 22 Jul 2009 11:30:43 +0200
Message-ID: <4A66DC43.6060005@malform.no>
To: HTMLWG <public-html@w3.org>
Smylers On 09-07-22 07.01:

> Leif Halvard Silli writes:
> 
>> Suppose one wants to validate a page that embeds PHP, but that one
>> wants  to do so /prior/ to the execution of the PHP script:
>>
>>        <?php Print "Hello, World!"; ?>
> 
> How can that be a meaningful thing to do?


Well, for instance, you can use it to check that you added PHP 
inside <? ?> - that you added it correctly. And if you find that 
your end-result page doesn't validate, you can use it to look for 
the errors: Does the error before PHP is executed or not?

>  What if the PHP script emits
> something which causes an error, such as misnested tags?  The
> conformance checker would be giving the author the impression that the
> page is conforming, yet what gets sent to the browser clearly isn't.

If this is an issue that a validator engine should think about, 
then it should be through warning message saying that the page may 
not be valid /after/ the PHP code has been executed. (But then, 
what about /any/ form that updates the page - should the validator 
tell the author that the page might become invalid once readers 
have use the form?)

> And why should PHP have this ability and not other programming or
> templating languages, such as those which use <% ... %> or [% ... %]?

What an upside down question ... The PHP and the Biferno language 
have chosen to use the <?instruction ?> syntax, thereby using a 
format that is defined in HTML and XHTML and supported by UAs. In 
many other programming languages, the author can change the syntax 
to his/her liking - which is the way to achieve "justice", in this 
case.

Otherwise, if you use <%...%> and [%...%], then the code becomes 
visible in the browser. And this might be what you want. So it 
depends on your coding style preferences. It would be stupid to 
say that <% and <? should be treated the same. For instance, some 
PHP templating languages uses visible rendered syntax instead of 
<? ?> syntax.

> If this is deemed a useful feature there's nothing stopping a
> conformance checker developer providing an option for 'strip PHP tags',
> which could be implemented as a pre-processing step to passing the
> remaining content to an HTML 5 parser.  Or indeed for any other template
> syntax, regardless of whether it resembles SGML processing instructions.
> But doing so doesn't require the language itself to be warped to allow
> this.

<? > doesn't warp HTML.

Do we want the anomaly that <?php ... ?> is valid XHTML 5, but 
invalid HTML 5? What about the UA support, should it be ignored? 
What about current validators - Validator.w3.org and HTML Tidy? 
And so on. Should we pretend that support for <? > doesn't exist?
-- 
leif halvard silli
Received on Wednesday, 22 July 2009 09:31:23 UTC

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