From GridLAB-D Wiki
bool - Boolean property type
Synopsis
class name { bool variable; } object name { variable TRUE|FALSE|0|1; }
Description
Boolean values are represented using the bool property type.
FALSE
The value FALSE is represented by the value 0.
TRUE
The value TRUE is represented by the value 1.
Example
To declare a boolean value in a class use the syntax
class my_class { bool my_boolean; }
To define a boolean value in an object use the syntax
object my_class { my_boolean value; }
where value is FALSE, 0, TRUE, or 1.