The SET TAB (abbreviated SE TA) command enables the structured tab
 feature and sets the logical tab size.

 Format: SET [NO]TAB n

 where n is the number of columns in a logical tab stop.

 With the structured tab feature, EDT keeps a counter of the tab level,
 which is set to 1 when the SET TAB command is issued. When you use the
 tab key in change mode at the beginning of a line, EDT inserts enough
 tabs and spaces to move the cursor to the column defined by the level n
 times the tab size.  Change mode nokeypad commands can alter the tab level.
 The structured tab feature is disabled by default.

 The tab size set by the tab command is also used by the TABS ADJUST
 command.