If you don't know anything about php non alpha numeric code you should read Gareth Heys Tutorial first:
Tutorial.
I used the following charset: $_=+();
As you can see only 7 chars.
In the end the function log will be created,because this won't exceed the memory limit. In the beginning I created the php function assert and it was 99 mb large php file, way too big to get executed.
Lets start
To begin with we need a way to get a string. But how? To start with we can create numbers by increasing a non-existing variable:
$_=++$_+(++$_);$_=++$_+(++$_);
This will store the number 9 in $_. Ok, but with numbers we can't create any function name...
To Infinity and beyond
The simple trick is to count on to infinity, which will store the constant INF in $_. So the first big block of (++$_) is simple counting to infinity. But INF is a constant not a string, so we can't increase it. Now the alias _ for gettext helps. This function is nice, because it assumes that we meant the string INF and will pass it back to us. So the code will look like this $_=_($_)
