"PHP 4.0 is not a trivial upgrade to an existing product--it's a
total re-write with backward compatibility to the 3.x technology.
It's actually quite a feat, because they kept the compatibility
with version 3.x, but made some radical changes under the hood.
First and foremost, the 3.x product was really an interpreted
language, each line of code was evaluated during the execution of
the server side page."
"With version 4.0, the functional difference is actually
quite staggering--the server actually compiles the code on the fly,
and then executes the code, with dramatic improvements in speed as
you can guess."
"There's actually more to it than this. Zend Technologies now
provides an optimizer (not a free product, by the way--they have to
make a living somehow) for people who have created massive PHP
projects and want to create more efficient code bases."
"As if that's not enough, PHP has been separated completely from
Apache, so that the language itself can be embedded into other
products that need scripting languages. This is absolutely awesome
news, as far as I'm concerned. Possibly even bigger news that PHP
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