1. A storage medium encoded with instructions, wherein the instructions when executed comprise: saving a plurality of values for a variable specified by a condition after a respective plurality of encounters of a breakpoint by a program that modifies the variable; selecting one of the plurality of values based on a condition; determining whether to stop execution of the program at the breakpoint based on the one of the plurality of the values; stopping execution of the program at the breakpoint if the determining is true; and allowing the program to continue to execute if the determining is false.