screen.display utility

The screen.display utility displays a screen and waits for a selection.


call "dm,bp, screen.display"


The common variables defined in dm,bp,includes must be set as follows:

screen Array of up to 512 options. The options are displayed in a columnar format, prefixed by their number on 3 digits. The routine then waits for user input. The first 10 options can be selected by entering their number. Other options can be selected by typing the first letter of the option or by moving the cursor (CTRL+N: Next; CTRL+B: Back; CTRL+J: Move left; CTRL+K: Move right). Array of help messages. The message displays starting at the line specified by screen.msgline. A value mark is a line separator. If nonnull, the help displays starting at the line specified by screen.msgline when the cursor is moved to the corresponding option.
screen.size Number of actual entries in the screen array.
screen.title Title. Displayed underlined.
screen.x Coordinates of the upper-left corner of the menu, starting at 0,0.
screen.y Coordinates of the upper-left corner of the menu, starting at 0,0. Option number to set as active (highlighted).
screen.lastline Last line available to display the menu. If there are more options than there are available lines, the menu displays in columnar format. If there are more columns than can display on the 80 column screen, some columns do not display.
screen.width Width of an option. The default is 35 characters.
screen.doselect Boolean. If true, the user can select more then one option before validating by pressing the Spacebar. An asterisk displays in front of the selected options. The list of selected option numbers is returned in
screen.msgline Line number where the help messages can be displayed. The message area extends to the end of the screen.
screen.notice If nonnull, contains the name of an external subroutine that is called periodically. The main program can provide a polling routine to display user information or perform some periodic task.


These variables are then updated: User selection:
n Option n.
Q Quit or Esc.
X Exit to TCL. If screen.doselect is true, contains the list of option numbers selected by the user, separated by an attribute mark.
screen.maxsize Last line actually displayed on screen. In most cases, it is screen.y+screen.size. However, if there are too many options to fit in one column, this variable reflects the actual last line on screen. This is used by screen.erase.


include dm,bp,includes
* Init the screen
* ---------------
call "dm,bp, screen.init"
* Clear the whole screen
* ----------------------
crt @(-1)
* Build the menu
* --------------
screen.x=0 ; screen.y=0 ;* Top left corner
screen(1)="User" ;* Option 1
screen(2)="Account""User name" ;* Help messages"Account name"
screen.size=2 ;* Number of options ;* Option 1 is default
screen.msgline=23 ;* Help line
* Display the menu
* ----------------
call "dm,bp, screen.display"
begin case
      * Back to TCL
      * User typed ’q’ or Esc
   case 1
      * Selected an option from 1 to screen.size
end case