debug {base}R Documentation

Debug a function


Set or unset the debugging flag on a function.




fun any interpreted R function.


When a function flagged for debugging is entered, normal execution is suspended and the body of function is executed one statement at a time. A new browser context is initiated for each step (and the previous one destroyed). You take the next step by typing carriage return, n or next. You can see the values of variables by typing their names. Typing c or cont causes the debugger to continue to the end of the function (or loop if within a loop). You can debug new functions before you step in to them from inside the debugger. Typing Q quits the current execution and returns you to the top–level prompt. Typing where causes the debugger to print out the current stack trace (all functions that are active). If you have variables with names that are identical to the controls (eg. c or n ) then you need to use print(c) and print(n) to evaluate them.

In order to debug S4 methods (see Methods), you need to use trace, typically calling browser, e.g., as
trace("plot", browser, exit=browser, signature = c("track", "missing"))

See Also

browser, trace; traceback to see the stack after an Error: ... message; recover for another debugging approach.

[Package base version 2.2.1 Index]