SB-KERNEL:TWO-ARG - what does this mean when used in debugger backtrace?

Question

I'm (a newbie) debugging my Lisp code (Common Lisp, Steel Bank, SLIME).

The first frame in my backtrace is:

0: (SB-KERNEL:TWO-ARG-> 1 NIL)

My question is:

• what exactly does "SB-KERNEL:TWO-ARG" mean/check/do ?
• where should I have looked this up online myself? (I tried searching for it but cann't find any reference to it other than in other Backtrace outputs).

Answer 1

You can use "v" on a frame to jump to the definition of the function in the debugger.

In this case, the function sb-kernel:two-arg-> sounds like a specialized version of > that is called when there are exactly two arguments provided. If the arguments are 1 and NIL, you'll get an error because NIL is not a number.

I'm not sure how you'd figure this out yourself, except by practicing and asking questions.