Exploring Expect

Moving Up And Down The Stack

The current scope can be changed by the u and d commands. u moves the current scope up, while d moves it down. Interactive variable accesses always refer to the current scope.

dbg5.11> u
dbg5.12> w
 0: expect -D 1 debug-test.exp
 1: p1
*2: p2
 3: p3
 4: set m 0
dbg5.13> set c
4

Both u and d accept an argument representing the number of scopes by which to move. For example, "u 2" moves from scope 2 to scope 0.

dbg5.14> u 2
dbg5.15> w
*0: expect -D 1 debug-test.exp
 1: p1
 2: p2
 3: p3
 4: set m 0

An absolute scope is also accepted in the form of "#" followed by a scope number, such as "#3“.

dbg5.16> u #3
dbg5.17> w
 0: expect -D 1 debug-test.exp
 1: p1
 2: p2
*3: p3
 4: set m 0

When an absolute scope is named, either u or d may be used, irrespective of which direction the new scope lies.

Moving the scope does not affect the next script command that is about to be executed. If a command such as s or n is given, the current scope is automatically reset to wherever is appropriate for execution of the new command.