Operator Scope of Action:
Operator First Added:
In queries and conditional action code expressions, starting an attribute name preceded by a $ character functions as a shortened form of the Boolean test for a true value. Thus the following are functional equivalents:
In both cases the result is true if the value of $MyBoolean is true.
In all other contexts, the $AttributeName syntax implies a reference to that attribute.
Usefully Tinderbox also useful supports such short-form $AttributeName tests for all the other attribute data types, returning true if the attribute has a non-default value. Per data type, this equates to long form tests like:
In all these cases a short-form test returns true if the attribute value is not the default for that data type.
A reverse short form test is also offered by (!$AttributeName), i.e. the same syntax with a preceding exclamation mark and enclosing parentheses. In theory, the latter parentheses aren't necessary, but in practice it helps Tinderbox when parsing a query.