, d b sets breakpoints on the expression under the cursor. If the expression is a function definition, then it is marked as instrumented by the debugger along with any calls to that function.
Skip over lazy functions
o (out) will jump out of evaluating an expression.
Use out to jump over evaluating code that has functions generating lazy infinite sequences, such as
cycle. The debugger will then evaluate those functions in their outer expression where it should be safe to do so.