Hello,
Being unexpectedly struck by influenza with high
temperature (40C) I remained at home and wrote the very first scratches
of PHP tag libraries. It is strange that such an issue had not been
discussed here in the past (or maybe I have missed the mails as I don't
follow very regularly the list).
Below is a short example how it looks from the
user's perspective (my explanations are unnecessary as the sample is quite
self-explanatory):
test_newtag.php:
-----------------------
<?phptaglib location="newtag.ptd"
?>
<body>
<newtag></newtag>
</body>
-----------------------
<newtag></newtag>
</body>
-----------------------
newtag.ptd:
-----------------------
<?xml version="1.0"
encoding="ISO-8859-1" ?>
<!DOCTYPE phptaglib SYSTEM
"phptaglibrary.1.0.0.dtd">
<phptaglib>
<lib location="newtag.php" />
<phptag>
<name>newtag</name>
<class>NewTag</class>
</phptag>
</phptaglib>
<lib location="newtag.php" />
<phptag>
<name>newtag</name>
<class>NewTag</class>
</phptag>
</phptaglib>
-----------------------
newtag.php:
-----------------------
<?php
class NewTag
{
function doStartTag()
{
print("New Tag: start<br />\n");
}
class NewTag
{
function doStartTag()
{
print("New Tag: start<br />\n");
}
function
doEndTag()
{
print("New Tag: end<br />\n");
}
}
?>
-----------------------
{
print("New Tag: end<br />\n");
}
}
?>
-----------------------
phptaglibrary.1.0.0.dtd (not really necessary
here):
-----------------------
<!ELEMENT phptaglib (lib+,
phptag+)>
<!ELEMENT lib EMPTY>
<!ATTLIST lib
location CDATA #REQUIRED>
<!ATTLIST lib
location CDATA #REQUIRED>
<!ELEMENT phptag (name,
class)>
<!ELEMENT name
(#PCDATA)>
<!ELEMENT class
(#PCDATA)>
-----------------------
output:
-----------------------
<body>
New Tag: start<br />
New Tag: end<br />
</body>
New Tag: start<br />
New Tag: end<br />
</body>
-----------------------
The implementation is quite straightforward - I
have added new tokens and parser rule for the taglib declaration. Then the
xml taglib description is parsed with expat and stored in hash
together with the compiled PHP bytecode of the taglib includes. Finally the
output is hooked, once again via the XML parser to substitute the custom
tags with the output of the corresponding methods.
I have a lot of things to do (at least one
week) before I will be able to post here fully working patches,
however I want to hear what do you think.
Custom tag libraries are cool today and should be
supported wherever is possible...
Best regards:
--
Alex
