[htmltmpl] Validation and vanguard_compatibility_mode

[Jacob L. A. <jan...@ge...>]

Hi,

Before I get into my "me too" validation bit, I want to express my thanks to 
Michael Peters and the others that have brought HTML::Template to where it is. I 
love the light-weight nature and assistance keeping presentation separate from 
business logic. Having the filters/escape values for html, js, and url is a 
great bonus.

I recently gave Eclipse EPIC a hand and thought I may as well edit the HTML and 
template files in Eclipse as well, via it's built-in Web Tools Platform (WTP) 
code. Right away I ran into validation errors with attribute values that needed 
HTML::Template VARs, like this:

<link rel="stylesheet" href="<!-- TMPL_VAR NAME=BASEURL -->/admin.css" 
type="text/css">

The WTP parser would get confused and say that the link tag wasn't closed, just 
like it did for Dietrich Streifert in his question from 5 Jul 2006.

http://comments.gmane.org/gmane.comp.lang.perl.modules.html-template/1628

Scouring around, I came across the vanguard_compatibility_mode "error detection 
option" that I had been ignoring because I'm not at Vanguard Media. Using 
%BASEURL% instead of anything starting and ending with html-looking <> tags. 
This worked pretty well.

Like others have been, I am concerned about the viability of using that flag 
based on it's name and documentation. Also, I miss the filter/escape available 
using the standard method and I wouldn't mind still having die_on_bad_params.

http://search.gmane.org/?query=vanguard_compatibility_mode&group=gmane.comp.lang.perl.modules.html-template

I appreciate the HTML comment (<!-- -->) option of HTML::Template. It helps a 
lot. I'm not a fanatic about valid HTML but these helpful IDEs are. I would love 
some optional syntax to use inside of tags so they don't look like unclosed 
start tags. Here are some initial ideas:

1) Have a percent_escapes option that acts like an alias to 
vanguard_compatibility_mode, except that it doesn't disable die_on_bad_params if 
possible.

2) Be able to select a filter, maybe with an extra leading character like this:
    * %:BASEURL% - HTML escape filter
    * %=BASEURL% - URL escape filter
    * %!BASEURL% - JavaScript escape filter
   or by replacing ~(TMPL_ PATTERN)~ with <TMPL_ PATTERN> like this:
    * ~TMPL_VAR NAME="BASEURL" ESCAPE="HTML"~
   I prefer the first option.

I hope this isn't feature creep. I appreciate that HTML::Template has provisions 
to be more pre-output validation friendly than other systems, including the 
prominent non-Perl ones. I was hoping that changes like this would close a 
frequently annoying hole in it's validation friendliness.

Thank you for your thoughts,
-- 
Jacob Anawalt
Gecko Software, Inc.
jan...@ge...
435-752-8026