ENVIRONMENT -- Changes or identifies an environment.
FORMAT
statement-id
-Run
Environment -User
-Caller
-Sub
REQUIRED ARGUMENTS
None. If you do not supply an argument, the command returns the
name of the current environment.
OPTIONAL ARGUMENTS
statement-id Sets the user environment to the given location. Usually,
you just specify a routine-name, sometimes you specify a
particular statement-number within the routine. When
dealing with recursive routines, you may also want to
specify an activation-number.
-Run Sets the current environment to the run environment.
-User Sets the current environment to the user environment.
-Caller Sets the user environment to the statement that called the
current routine. The current routine must be active. This
option and -SUB provide a convenient way to "walk" up and
down the call stack.
-Sub Sets the user environment to the routine called by the
current routine. The current routine must be active. This
option is essentially the opposite of -Caller.
DESCRIPTION
Use the ENVIRONMENT command to set or describe an environment. The
"environment" is the default routine that DEBUG searches when you do not
explicitly specify a routine. DEBUG recognizes three different kinds of
environments:
user environment -- the routine you name with the ENVIRONMENT command.
run environment -- the routine at which the program is stopped.
current environment -- whichever of the two previous environments that
DEBUG is currently using in its calculations.
Many debugger operations implicitly reference the current environment.
For example, if you ask to examine variable X, and don't qualify X
with a particular routine name, the debugger will show you the X visible
from the current environment. If X is not visible from the current
environment, for instance, if it is defined in another routine, then
DEBUG will not be able to find it.
Environment really only becomes important when you the program is stopped
in one module, but you want to access information stored in a different
module.
For full details, see Chapter 3 of the DOMAIN Language Level Debugger
Reference manual.