6 VICAR User Aids


6.1   VICAR Help
    6.1.1   HELP Command
6.2   VICAR TUTOR Mode
    6.2.1   General TUTOR Information 
    6.2.2   TUTOR-SCREEN Mode
    6.2.3   TUTOR-NOSCREEN Mode
6.3   VICAR MENU Mode
    6.3.1   General Menu Information 
    6.3.2   The MENUTREE
    6.3.3   Creating a Menu
6.4   Syntax Checking
6.5   Message Interpretation
    6.5.1   General Message Information 
    6.5.2   HELP-MESSAGE
    6.5.3   "?"

Within this section, a variety of user aids will be introduced. These tools will prove invaluable in all stages of the user's development. The aids being covered include Help, Tutor and Menu modes, syntax checking and message interpretation.

6.1 VICAR Help

The VICAR executive assists users of all experience levels. It is able to give on-line information and instructions to a user when trouble is encountered at any point in a session. The following types of "help" are available:

If questions still remain after exhausting these options, further assistance can be obtained by posting questions to the USENET newsgroup jpl.vicar or sending them to vicar@mipl.jpl.nasa.gov via email.

6.1.1 Help Command

General help information on VICAR can be obtained by typing help with no subcommand. General information is available on most commands used in the Command mode.

Syntax: General Help information.

    VICAR> help
Help on a specific topic can be obtained by using one of the following HELP subcommands:

	help-command	(default for help)
	help-proc  	(default for help)  
	help-message 	(Section 6.5.2)
help-command and help-proc are the defaults for help. VICAR locates the command or proc by first doing a search among an intrinsic command list and then, if not found, performing a hierarchical library search.

The -command subcommand displays information on the specified command. If a subcommand is specified, then the information displayed will be for the subcommand only.


    VICAR>help-command command=command[-subcommand]
Example: Display help on the command enable-script.

    VICAR>help-command enable-script
The -proc subcommand displays information on the specified proc or proc subcommand.


    VICAR>help-proc proc=proc[-subcommand]
Example: Display help on the proc label-list.

    VICAR>help-proc label-list
The -parm subcommand is used to request detailed information on a specified parameter of a proc or a proc subcommand.


    VICAR>help-parm parm=parm proc=proc[-subcommand]
Example: Display help on the parameter nl of the program gen.

    VICAR>help-parm nl gen
The -global subcommand is used to request a detailed description of the specified Global variable.


    VICAR>help-global variable=global_variable_name
Example: Display help on the global variable $aplib

    VICAR>help-global $aplib
The -hardcopy subcommand writes a disk file containing information from both the help-proc and from Tutor. This file can then be printed in order to obtain a hardcopy of the information. If an output filename is not specified the file will be named procname.mem and it will be located in the user's current directory.


    VICAR>help-hardcopy proc=proc [output=filename]
Example: Create a file (difpic.mem) of help information for the program difpic.

    VICAR>help-hardcopy difpic
An alternate method to obtain a hardcopy of the help information is to print the procname.pdf from the applications library.

6.2 VICAR Tutor Mode

6.2.1 General Tutor Information

Within VICAR there is a mode called "Tutor" which does exactly what its name implies. It tutors or assists the user in the use of procs and the parameters associated with them. Tutor not only permits the user to obtain more information concerning procs, but it actually permits the user to select parameters and then execute the proc via the run command.

Tutor mode can be accessed by any one of the following methods:

There are actually two modes of Tutor available.

TUTOR-SCREEN is a formatted terminal screen display (Section 6.2.2).

TUTOR-NOSCREEN is similar in style to the TAE Command mode but provides a different prompt, lists the parameters requested and allows a set of commands unique to a Tutor session (Section 6.2.3).

When tutoring is initiated, the mode entered by Tutor will be determined by the Global variable $tutor. It can be overridden by using one of the Tutor subcommands (-screen, -noscreen).


    VICAR>tutor[-subcmd] proc_name[-subcmd] [proc-parameters]
Example: Tutor the program label-list in SCREEN mode.

    VICAR>tutor-screen label-list
The proc-parameters field is optional and may contain a list of parameters. Parameters supplied on the Tutor command line become initial or default values in the Tutor session.


TUTOR-SCREEN mode commands allow the user to:

Upon entering Tutor mode the user is presented with the first page of a possibly multi-paged display showing information on each parameter of the selected proc or command. For each parameter, Tutor displays the following: the parameter name, a brief description of the parameter, its current value (if one exists), and a note on qualifiers defined for the parameter (if there are any).

EXPERT When a multi-valued parameter has more values than will fit on one Tutor screen, only one full screen is shown. Tutor maintains a "window" on the elements of the parameters. Unless a particular element is referenced (e.g., parm(i)= ), the display window includes the first element. This window may be moved by using the intrinsic command show.

The "+" adjacent to the page number in the upper right corner of the Tutor display indicates that there are more pages available within the display. If the character in that position is a period, there are no more pages.

Descriptions of Tutor mode user commands and special Tutor line editor keys can be found in Appendices 10.8 and 10.9, respectively.


The NOSCREEN mode of Tutor exists to support the following situations: hardcopy terminals, unsupported terminals for which VICAR can only operate in scrolling mode, low-speed terminals where the time for screen update is prohibitive, or personal choice (some users prefer the NOSCREEN Tutor mode).

NOSCREEN Tutor mode commands allow the user to:

There are operational differences between NOSCREEN and SCREEN modes. Features unique to NOSCREEN mode are:

Descriptions of Tutor mode user commands and special Tutor line editor keys can be found in Appendices 10.8 and 10.9, respectively.

Example: TUTOR-NOSCREEN Session

    VICAR>tutor-noscreen difpic
    proc "difpic", library "$R2LIB"
    Parameters requested:  INP, OUT, SIZE, SL, SS, NL, NS...
	INP= (no value specified)
	OUT= -- (null value)
	FORMAT= -- (null value)
	MOD= -- (null value)
    VICAR-difpic>list size

6.3 VICAR Menu Mode

6.3.1 General Menu Information

(At the current time, only a bare skeleton of the menu system is available in UNIX VICAR. Most of the information below is for the VMS system, but should apply to the UNIX system in the future.)

Menu mode is the VICAR alternative to Command mode. In Menu mode, a user invokes applications by locating and selecting them through a series of menus. Each menu is a terminal display containing categories, each describing either a more detailed menu or a proc to be executed.

There are two methods to access the VICAR Menu mode. Depending on system configuration, the user may enter the Menu mode when invoking VICAR. In this instance, the user is given a "ROOT" menu and the Menu prompt ?. Alternatively, the user can manually enter the Menu mode.


    VICAR>menu [name=menu_name]
Where: menu_name is the name of the desired menu.

If this is the first entry into Menu mode for the current session, the default menu is the ROOT directory defined by the host system. If it is not the first entrance, then the default will be the most recent menu the user accessed. The menu is located using the hierarchical library search unless the user explicitly specifies the library name of the menu.

Example: A typical menu screen.

    VICAR>menu name=root

The above figure is an example of the format of a menu terminal display. The categories are numbered entries arranged vertically on the screen. The prompt-line options are at the bottom of the screen arranged horizontally above the menu prompt.

At the menu prompt, ?, the user selects a category or enters a Menu option. If the category selected is a menu, the new menu is displayed. If the category selected is a proc, VICAR enters Tutor mode in order to prompt the user for the proc's parameters. After execution of the proc, the display of the last menu can be obtained by pressing the <CR> key.

If a Menu option is selected, VICAR executes the command. Menu options are limited to those found in Appendix 10.7. These allow only basic management functions which include: accessing, moving back up the menu hierarchy, making a transition to Command mode, and exiting VICAR.

EXPERT A user may switch back and forth between Menu mode and Command mode. When entering the Command mode from a menu (using command), the current menu and the path to the current menu are remembered. This context is automatically restored when Menu mode is subsequently re-entered.

6.3.2 The MENUTREE

(At the current time the Menutree is only available on VMS systems.)

WIZARD The ability to move forward or backward through the levels of a menu is essential to operating within VICAR. Unfortunately the user also runs the risk of conceptually "losing their place" in the system because of this flexibility. There is a program, menutree, available within VICAR which permits the user to generate a graphic representation of a selected menu system.


    VICAR>menutree [menu=menu_name] [output=output_option]

Where:	menu	specifies the starting menu name.  If omitted,
		the default value is the top of the current
		menutree (see Global variable $menus).
	output	directs the listing of the menutree:  
		= file	    -  create menutree.txt
		= printer   -  send to line printer
		= terminal  -  send to terminal (default)
Example: Menutree run on the menu presented in Section 6.3.1.


    ****************  VICAR HELP  INFORMATION  ****************
	       |> NUT
	       |- LEVEL3.
	       |  MDF-------|
               |            |> TAE$MENU:SAMPLE1.PDF
               |            |> DCL @TAE$MENU:GEOREF.COM
               |            |> DCL @TAE$MENU:TIEPOINT.COM
               |            |> DCL @TAE$MENU:PROJECTION.COM
               |            |> DCL @TAE$MENU:VARIATE.COM
	       |- LEVEL4.
	       |  MDF-------|
	       |	    |- ANNOT1.
               |            |  MDF-------|
               |            |            |- FONT
	       |	    |	         |- MASKV
   	       |	    |	         |- STARLAB
	       |	    |	         |- TEXTAD
 	       |	    |
	       |	    |
	       |	    |- DISPLAY1.
               |            |  MDF-------|
	       |	    |	         |- BROWSE
	       |	    |	         |- DISPLAYS
	       |	    |	         |- DISPOUT
	       |	    |	         |- EDIMAGE
WIZARD If Menutree cannot be located in TAE$UTIL, ask your system administrator for the proper location.

6.3.3 Creating a Menu

WIZARD A menu corresponds to a Menu Definition File (MDF), which is a text file created or changed by using the host system's text editor. MDFs contain the title of the menu, text describing each menu entry, name of the proc or menu files associated with each entry and help information for the menu. Further information on menu creation can be found in the TAE Command Language Programmer's Manual.

6.4 Syntax Checking

A user has the ability, within VICAR, to check the syntax of a procedure (Section 7.3) that has been written. This is particularly useful for procedures that will be run in the Batch mode. The syntax checker sets a switch which prevents VICAR commands from executing. However, all normal processing up to the actual procedure execution does take place, so any syntax or parameter errors that are visible to VICAR will be detected and reported to the user.

Once the syntax checker has been invoked, anything that is typed will be verified (e.g., VICAR commands or procs).


    VICAR>syntax check
BEWARE The syntax checker only verifies the wording to make sure all commands are valid VICAR commands. It does not check logic errors, existence of referenced files or availability of resources.

BEWARE All parameters required by a proc need to be supplied in order to successfully run the checker. Syntax check will fail when variables are assigned at time of execution (e.g., the proc camparan).

The syntax checker will remain invoked until the user turns it off wth the following command.


    VICAR>syntax nocheck
BEWARE The command let $switch=... should not be used in SYNTAX mode, since the syntax check flag is in $switch. By setting $switch to an absolute value, it is possible to accidently turn off the syntax check mode. To change other options within $switch, use the flag-add or flag-del commands. Further online Help information is available on flags or see Appendix 10.4.


    VICAR>help flag

6.5 Message Interpretation

6.5.1 General Message Information

VICAR has the capability of providing online information and instruction to a user when trouble is encountered. The user is presented with brief messages when the error occurs and can request additional clarification and guidance.

Brief error messages are one-line comments preceded, in brackets, by a "message key".


    [SYSTEM-KEY] Message

where:	[SYSTEM-KEY]  is the "message key"
	SYSTEM	      indicates which system issued the message: 
			      VIC2 - VICAR Run-time Library
			      TAE  - the TAE supervisor
	KEY	       is the specific identifier for the 
		       message given 
	MESSAGE	       is the text containing a comment from
Example: End of volume message.

    [VIC2-ENDOFVOL] End of volume (double tape mark) reached
In many cases, the brief error message adequately informs the user of the problem. However, in some cases the user might still be at loss as to what VICAR is trying to explain. In that case, there are two methods for obtaining further online assistance on the message interpretation:

In addition to the online error facilities, the user can make use of several other sources containing common message explanations, including:


The command help-message is used when the user wishes VICAR to expand upon the received message. VICAR responds with an explanation of the error message and a suggested course of action for the user.


    VICAR>help-message key=message-key
Example: Get more help on the end of volume message.

    VICAR>help-message key=vic2-endofvol


    The end of volume mark (double tape mark or double end 
    of file) was hit when trying to open a file on an input 

    User action:

    Scan tape to determine the actual number of files on it, 
    and make sure that the proc does not try to access a file 
    beyond that number. 

6.5.3 "?"

An alternate method to obtain the same Help information is to type the VICAR command "?". "?" is special in that no other parameters are allowed and it always causes VICAR to display help information on the last message received.



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