It has been a rather crazy last two weeks at work, so I didn't get a chance to revisit the type hinting matter. Unfortunately, while initial outpouring of support for inclusion of type hinting into PHP 5.3 and 6 was substantial, it all kinda petered out once more people started voting. To be specific, there is a large amount of support for the feature in general, but very few people seem to think it should go into 5.3.
I feel that 5.3 is the only release that would make this feature usable, since that is the version of PHP I could see myself using at work in a near future as well as a release other people would be using for the next few years, at least. PHP 6 is just very far a way from any sort of a release, let alone a production worthy version and at the same time there is no tentative agreement on making 5.4 in the near future. If it went to 5.3, which would be "work worthy" I could justify spending the time to maintain the patch across all branches, but with PHP 6 only, it is simply too impractical.
That said, at work we will transition to 5.3 soon, probably around 5.3.2/3 time, so I do need a type hinting patch. To that effect I've cleaned up and improved the old patch based on comments from various people, notably Stas and Dmitry (thank guys) and made a copy that I intend to use for work.
The patch is now pure type hinting, no more virtual types like SCALAR and NUMERIC, it also does not offer any type casting support. Basically its just a type hinting patch, with full reflection support. Since the last iteration of the patch the following improvements have been made:
1) Modify the parser to not reserve string/integer/etc... keywords used for type hinting. Won't break code that uses "class string", etc...
2) Added getTypeHint() reflection method to determine the type of hint a parameter has
3) Revised the parser (thanks Stas) to properly parse out type hints.
The patch can be found here:
http://ilia.ws/patch/type_hint_final.txt
and the test suit here:
http://ilia.ws/patch/type_hint_tests.tar.bz2
Update July 22, 2009
A bug was found by Gwynne, which prevented constants (other then NULL) from being used as default values of type hints, she was also kind enough to provide the patch for the problem. The patch was updated with this fix and an additional test was added for this eventuality. Thanks Gwynne!