BOOLEAN
Appears in a Definition dialog as a check box. It has one of two values: True (T) or False (F).
Example
In this example, the user is allowed to turn on or off the Hierarchical Numbering features on an IDEF0 diagram by selecting true or false.
DIAGRAM "IDEF0"
{
PROPERTY "Hierarchical Numbering"
{ EDIT Boolean LENGTH 1 DEFAULT "F" }
..
}