Checks if a variable's base type is boolean.
IsBool ( variable )
| variable | The variable/expression to check. | 
| Success: | 1. | 
| Failure: | 0 if expression is not boolean type. | 
See language datatypes for a detailed description.
IsArray, IsBinary, IsFloat, IsHWnd, IsInt, IsMap, IsNumber, IsPtr, IsString, VarGetType