Before version 10.0, there was a menu item, Evaluation → Interrupt Evaluation..., which could be used to interrupt a calculation without aborting it. It would bring up this window:
It was possible to enter a subsession, examine the kernel state, then resume the calculation using Return[].
How do I access this functionality in version 10.0 or later?
The menu item is gone, but the functionality is still there in version 11.0.
It can be accessed by a keyboard shortcut:
. on OS X, on Windows and LinuxThe front end token is called
"EvaluatorInterrupt"It can be used e.g through a palette button.
Alternatively, use Evaluation → Evaluate in Subsession for similar functionality. E.g.,
Table[Pause[1]; i, {i, 30}]
Now enter i and evaluate it using the above menu item before the Table has finished running. You will see the current value of i.