I think this is great. I do have a question/suggestion though.
I have just been looking at the computational accuracy of the c language, specifically how accurate an angle can you precisely work with. It turns out that there is a 15 decimal point limit to PI, even if you declare it as a long double. So I was wondering, wouldn't it be good to mention the computational accuracy of PDL. For instance, can it use PI to 50 decimal places and still be accurate? Can a PDL data type hold huge numbers, or can piddles be a Math::BigInt, etc.
I've been reading that Fortran (on which PDL is based) is superior to c in this regard, but is PDL?