The ordinary Lisp debugger provides the ability to suspend evaluation of a form. While evaluation is suspended (a state that is commonly known as a break), you may examine the run time stack, examine the values of local or global variables, or change those values. Since a break is a recursive edit, all the usual editing facilities of Emacs are available; you can even run programs that will enter the debugger recursively. See Recursive Editing.
| • Error Debugging | Entering the debugger when an error happens. | |
| • Infinite Loops | Stopping and debugging a program that doesn’t exit. | |
| • Function Debugging | Entering it when a certain function is called. | |
| • Variable Debugging | Entering it when a variable is modified. | |
| • Explicit Debug | Entering it at a certain point in the program. | |
| • Using Debugger | What the debugger does. | |
| • Backtraces | What you see while in the debugger. | |
| • Debugger Commands | Commands used while in the debugger. | |
| • Invoking the Debugger | How to call the function debug.
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| • Internals of Debugger | Subroutines of the debugger, and global variables. |