# accessing PHPs AST

- Thread: https://externals.io/message/46265
- Original archive: https://news-web.php.net/php.internals/46265
- Started by Raphael Pigulla on 2009-12-02T17:35:05+00:00
- Messages: 3
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## #46265 — Raphael Pigulla — 2009-12-02T17:35:05+00:00

URL: https://externals.io/message/46265#46265

Hello,

I'm trying to alter existing PHP code by transforming its AST. From what
I've read, the Zend Engine does a one-pass compile and thus offers no way to
access the AST. (Whether this is a good or a bad idea doesn't really matter
at this point, so let us stay away from that discussion for now.) 
Other possible solutions I've come across are phc [1], rphp [2] and PHP
Depend [3]. Unfortunately, the first does not support PHP 5.3, the second is
still in a *very* early stage of development and the third does not allow
'unparsing' and is not particularly fast either (which is only a minor
concern, but still).
The last idea I had was approaching this from the Java side and use the
parser that comes with PDT [4] or PHPEclipse [5], but I haven't yet figured
out how to do this yet, and I'm not even entirely sure if this can be done
outside of Eclipse (of course it should, but who knows).

As you can see, I haven't really found a satisfactory solution yet, so any
help is appreciated.

regards
raph

[1] http://phpcompiler.org/
[2] http://code.roadsend.com/rphp/
[3] http://pdepend.org/
[4] http://www.eclipse.org/pdt/
[5] http://www.phpeclipse.com/

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## #46266 — Sebastian Bergmann — 2009-12-02T18:23:08+00:00

URL: https://externals.io/message/46265#46266 · In reply to: #46265

Am 02.12.2009 18:35, schrieb Raphael Pigulla:
> As you can see, I haven't really found a satisfactory solution yet, so any
> help is appreciated.

 pecl/parse_tree (if it (still) works) provides access to the parse tree
 of PHP code in the form of XML. The XML can be manipulated and then
 transformed back into PHP code.

 What kind of AST transformations are you thinking about?

-- 
Sebastian Bergmann                    Co-Founder and Principal Consultant
http://sebastian-bergmann.de/                           http://thePHP.cc/

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## #46351 — Raphael Pigulla — 2009-12-08T08:29:08+00:00

URL: https://externals.io/message/46265#46351 · In reply to: #46266

> pecl/parse_tree (if it (still) works) provides access to the parse
 > tree of PHP code in the form of XML. The XML can be manipulated and
 > then transformed back into PHP code.
PECL::Parse_Tree is still in alpha state and has not been updated since 
January 2007, so I don't have too much confidence in it being 5.3 compliant.
For now I've opted to approach this from the Java side using DLTK and 
PDT which is very powerful and fast. Plus, it is my hope that - PDT 
being a widely used PHP IDE and all - the parser will always be fairly 
up to date.

 > What kind of AST transformations are you thinking about?
At this point it's only a little side project. Eventually, I hope to 
build some sort of PHP precompiler for our CI server that can help us 
with QA and such (e.g., checking pre- and postconditions). It is in a 
way very similar to AspectPHP, but may very well go beyond what is 
possible with AOP (at the cost of being not as flexible, obviously). But 
again, this project is still in a very early stage; I'm just writing the 
very first prototype to see how far DLTK can take me.

regards
Raphael