expression isa type
The isa operator evaluates to true if the given value can be converted to the given type. If the given value cannot be converted to the given type, the isa operator evaluates to false.
In HyperTalk, you can only use isa to test if some value is an integer, a number, a date, a point, or a rectangle. However, the test for a date will accept just about any string to the point of being nearly useless, and the tests for point and rectangle are broken: if the value is not a comma-delimited list of integers, the expression will trigger an "Expected integer here" script error instead of evaluating to false. XION will only consider something a date if it can actually be converted to one, and will never trigger a script error when evaluating the isa operator.
are, instanceof, is a, is an