must I customize firmware for controller?

I'm unable to buy an extruder controller from Makerbot (out of stock) so I'm rolling my own. I'm using a boarduino, an IRF510A to power the heater, and a nifty breakout board for the Allegro 4983 stepper driver (does microstepping to 16X!) as my protoboard version, prior to having a custom board made.
While I wait for my SN75176 to arrive, I breadboarded the rest of my circuit and opened the firmware in the IDE. I'm feeling a bit inadequate right now. The c++ code looks intimidating. I'm not so sure, now, that my mediocre c skills will allow me to adapt this code to my stepper driver. Any hints from more experienced hands would be welcome.

C++ is very similar to C in microcontroller land; here's an example.

C++

someThing s = new Thing(12345);
s.doStuff();

C

someThing s;
Thing_init(s, 12345);
doStuff(s);

I rewrote the FiveD firmware in C so it fits on an arduino if you want a look at an example. link below

---

-----------------------------------------------
Wooden Mendel
Teacup Firmware