screen.display

displays a screen and waits for a selection.


Input :

The COMMON variables defined in 'dm,bp,includes screen.inc' 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).

screen.help Array of help messages. The message is displayed starting at the line specified by 'screen.msgline'. A value mark is a line separator. If non null, the help is displayed 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
screen.y Coordinates of the upper left corner of the menu, starting at 0,0.

screen.active 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 is displayed in columnar format. If there are more columns than possible to display on the 80 columns screen, only some columns are displayed.

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 hitting the <space> bar. An asterisk is displayed in front of the selected options. The list of selected option numbers is returned in 'screen.select'.

screen.msgline Line number where the help messages can be displayed. The message area then extends up to the end of the screen.

screen.notice If non null, contains the name of an external subroutine which is called periodically. The main program can provide a polling routine to display user information or perform some periodic task.


Output :

The following variables are then updated:

screen.active User selection:
n : Option n
Q : Quit or ESC
X : Exit to TCL

screen.select If 'screen.doselect' is true, contains the list of option numbers, separated by an attribute mark, selected by the user.

screen.maxsize Last line actually displayed on screen. In most cases, it is screen.y+screen.size, but, if there are too many options to fit in one column, this variable will reflect the actual last line on screen. This is used by screen.erase.