If received an error message, one can use taceback function to find out in which function the bug is:
> traceback()
After located the specific function, one can use debug funtion to find the specific line of code containing bug. For example, the function name is SS.
> debug(SS) > SS(2, x) Browser[1]>
One is now in what is called the "browser". Here one can enter 1 of 4 basic debug commands (n, c, where, Q).
<Enter>
Go to the next statement if the function is being debugged. Continue
execution if the browser was invoked.
c or cont
Continue execution without single stepping.
n
Execute the next statement in the function. This works from the browser as
well.
where
Show the call stack.
Q
Halt execution and jump to the top-level immediately. To view the value of
a variable whose name matches one of these commands, use the print()
function, e.g. print(n).
One can use debug(the_2nd_level_function) to go deeper.
Hide Comments