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bgrevelt / FakeSwConstructionRepo

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QL: Handle undefined values #40

Open bgrevelt opened 7 years ago

bgrevelt commented 7 years ago

The semantics of expressions and question variables is standard, except that an unbound variable (= unanswered question) has the special value undefined . Any expression referring to an undefined variable is undefined itself. In conditional context, undefined means false .

bgrevelt commented 7 years ago

So a good test case for this would be

form test { q1 : "question one" int if(q1 >= 50) { greaterThanQuestion : "This question should not be shown" bool } if(q1 <= 50) { lessThanQuestion: "This question should not be shown either" bool } }

Since q1 is undefined at start up time, neither one of the if statements should resolve to true.