Application steering is the interactive manipulation of a program with the purpose of affecting its behavior. It allows the user to monitor and control their application during execution. The tools that IPython provides to enable some basic forms of application steering have been laid out in this chapter. This section will limit itself to describing some simple applications.
The simplest and oldest form of application steering is using a debugger. Using a debugger provides the ultimate in control over an application – the entire state can be accessed and modified, and execution can proceed in arbitrarily small increments. While using a debugger is well-understood, it has the drawback of requiring an extremely high degree of user interaction. This may seem counterintuitive: after all, if some interactivity is good, should not more be better? But consider running 1500 simultaneous tasks, and trying to debug them all at the same time. If nothing else, this would...