How to debug within R

In my words this is how to debug within R:

• If you want to print a stack trace for the most recent exception
  • then use traceback
  • you may or may not have the source
• If you want to set a breakpoint at a specific location in the code
  • then use browser
  • you must have the source
  • it may be conditional
• If you want to set a breakpoint on a function at its
  entry point
  • then use debug
  • you may or may not have the source
  • delegates work to browser
• If you want to install a global exception handler that will immediately start
  debugging
  • then use recover
  • you may or may not have the source
• If you want to add watch statement to a function
  • then use trace
  • you may or may not have the source