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Optional Facilities

Five optional facilities exist allowing the user the possibilities of,

	a) Controlling the text-window scrolling characteristics.
	b) Trapping errors in a loop or procedure.
	c) Logging your UniPOPS commands in a disk file.
	d) Undoing the actions of the previous one or two commands.
	e) Turning on or off the ability to make hardcopies.

These facilities will now be described in the above order.

The Scrolling of the Text Window

The pair of verbs FULLOFF and FULLON will toggle the scrolling of the text window between "always-scroll" and "page-at-a-time" modes respectively. With FULLON in force, the screen stops scrolling each time that the text-screen page is full, and the program waits until you strike <CR> for the next page, c or C to return to FULLOFF, t or T for a TCOPY (see Section 12.4) copy of the present text-screen window, or ^C to return to the command-level prompt.

FULLOFF is the login default.

Trapping Errors in Loops and Procedures

The pair of verbs ERROFF and ERRON allow different handling of any errors detected in a loop, procedure, etc., which would normally result in their termination. ERRON, the default setting, will indeed result in the termination of the current loop or procedure. However, with ERROFF in effect, UniPOPS will not terminate the loop or procedure on encountering an error, but will set the adverb ERRCODE to a non-zero integer, and continue after switching ERRON into effect. ERRCODE can be IMMEDIATELY tested by the user, and appropriate action taken. When an operation is completed successfully, ERRCODE is set to 0.

Suppose that you wish to examine all scans between 1000 and 1020, printing the header for those that are present, and warning of those that are not. Then prepare the procedure,

	: 	GET I_Z
	:	END

To check the scans, now type,

	>SCANCHK(1000, 1020)

Logging UniPOPS Commands

Using the verbs LOGON and LOGOFF, it is possible to log in an external file the UniPOPS commands that you enter. This "command-logging" file can be reread and executed in UniPOPS later using the BATCH command (see Section 13.9). The "command-logging" file will accumulate all UniPOPS commands given after invocation of the verb LOGON, up to, and including, the next use of the verb LOGOFF. If the file already contains commands from a previous use of LOGON, the new commands will be appended to the end of the file.

The name of the current "command-logging" file is listed in the FILES table at login, and can be seen at any time by using the pseudo verb FILES (see Section 5.2). To change the present "command-logging" file for another, the pseudo verb CHNGFILE is used (see Section 5.3). For this operation, the file-interface-id code for the "command-logging" file is 12. The pointer adverb LOGFILE has the value of 12 and can be used in place of the 12 (it may be easier to remember LOGFILE than remember that the correct file-interface-id code for the command-logging file is 12. Suppose that you wish to create a new file CLF and attach this in place of the present "command-logging" file, then type,




The "command-logging" file can be directed to the printer using the pseudo verb LASER (see Section 12.1).

Suppose you know that you are about to enter a set of commands that you will want to run again the next time that you use UniPOPS. You could save these in a new "command-logging" file called NEXT.TIME by typing,

	>The set of commands that you will rerun .........

Now, next time that you run UniPOPS, and wish to repeat the above set of commands, type,


Correcting the Effects of a Wrong Command

The pseudo verb UNDO tries to undo (usually successfully) the action of the previous command line. A second invocation of UNDO will undo the action of the command line before that. It is not possible to undo to any deeper level. However, before UNDO will function, the verb UNDOON must be in effect. UNDOON is the default at login. The UNDO facility can be turned off via the verb UNDOOFF. UniPOPS will run somewhat faster with UNDOOFF, although UNDO can be a very useful feature if you are worried about entering a disastrously-wrong command !

Suppose that after invoking the verbs HANNING and BASELINE you wish to return to the situation before these commands were used. Type,

	>UNDOON 	(Either sometime previously, or as login default)
	>UNDO		(Undoes the BASELINE command)
	>UNDO		(Undoes the HANNING command)

Note that UNDO will not undo any action which has updated a disk file (i.e. EDIT, SAVE, KEEP, STORE. etc.), or the two- and three-dimensional operations detailed in Chapter 16.

Making Hardcopies

The verb pair COPYON and COPYOFF allow you to turn on or off the ability to make hardcopies with GCOPY or TCOPY, (see Section 12.4). COPYOFF will speed up most graphical display routines. The UniPOPS default condition is COPYON.

Suppose that you wish to make a number of "trial runs" of the two-dimensional contour plot program QCONTOUR (Section 16.7.5), before taking your final hardcopy. To save yourself time, your first "trial run" should look like,


When you are sure that your plot parameters are those you want for the hardcopy, type,


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