Docs for Hacking PBP?

PBP is a great program...I just want it greater.
Is there a way to call functions internal to the compiler?
Add keywords to the language?

Here's the motivation.
There are a lot of neat functions in the serial in/out commands
for parsing text into variables. Problem is that my input
is from a serial input buffer, or a GPIB interface. I'd like to use
those text parsing functions on my input, not just direct serial
port access.

Is there a reliable way to call internal compiler functions from
a PBP program?

How about documentation to help with direct modification of the compiler?

Here's an example...
I need RS-232 RZ output to implement serial infrared capability to talk
to my PDA. I modified PBPBIC14.lib to implement that function.
That only worked because there was a non-used parameter passed
that I could detect in the .lib file. Would be helpful to have more info
on the way parameters are passed from the source to the .lib functions
and extend it.

What issues will I encounter if I try to call a PBPPIC14.lib
subroutine from within my basic source code? Will it even let me do that?

Before I go try to reverse-engineer it, thought I'd ask if anyone already had
any useful tools.

Thanks, mike