3.3 Using Debugger commands

3.3.7 Control transfer

• The:r command returns a value to the caller of the current frame.

• The:f command reexecutes the current frame. The command displays the expression to be evaluated and prompts for confirmation before evaluating the expression.

• The:u command unwinds the stack to the current frame. The process of unwinding the stack returns to the dynamic environment for the current frame and returns control to the Debugger in the current frame.

• The:x command sets or clears a trap-on-exit from the current frame. A trap on exit suspends the execution of a function immediately after the function returns. Traps can be used to stop execution of a program at a particular point so that you can examine the state of Lisp at that point. This command traps all exits, including throws.

With no argument, this command will toggle a trap from the current frame. With an argument oft, this command sets a trap from the current frame. With an argument ofnil, this command clears a trap from the current frame.

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