
The BLANK Clause
The BLANK clause clears a line of a screen or the whole screen
before a screen item is displayed.
General Format

Directives
- In addition to Compiler directives which provide flagging and
modify the reserved word list, the following directive may impact either the
syntax or semantics described in this section.
-
OLDBLANKLINE - specifies that the BLANK LINE clause
has the same effect as ERASE EOL; that is, all characters to the right of the
cursor are deleted.
Syntax Rules
- The BLANK SCREEN clause can be specified in any screen
description entry.
- The BLANK LINE clause can be specified only for elementary items.
General Rules
- The BLANK SCREEN clause is executed before DISPLAY of a screen
data item, no matter where it appears. If the clause is specified, all the
screen is cleared and the cursor is placed at line 1, column 1.
- When BLANK LINE is specified, blanking begins at column 1 of the
line specified for the screen data element in whose description it is included
and continues through the end of the line. The cursor remains in the same
position as before the BLANK LINE was actioned.
- If neither the BLANK nor the ERASE clause is specified, only the
particular character positions corresponding to the screen data element are
modified when the element is displayed. The rest of the screen content remains
the same.
- The BLANK SCREEN clause causes the screen to return to its
default foreground and background colors. For additional effects, if the screen
item is subject to a FOREGROUND-COLOR or BACKGROUND-COLOR clause, see the
topics on those clauses.
- The BLANK clause is ignored in an ACCEPT statement.
- When the BLANK SCREEN clause is used, only color options
(foreground-color and background-color) should be used on the same screen.
Other attributes are accepted but ignored.