What does !>> mean?

Question

I ran across a bit of if-statement code today in Lasso that I hadn't seen before. It looked like this:

if(#theFile !>> 'image');
    ...
/if;

How does the !>> operator work in Lasso?

Answer 1

The reference information for this operator in Lasso 8.5 is here[1].

In Lasso 9, you can find the discussion about "Containment Operators" here[2].

Discussing Lasso 9, in the expression

E1 >> E2

this is useful if the type of E1 includes a contains method, whose only parameter will be populated by the right operand; E2 in the example just above. This operator invokes that method for E1 with argument E2. That method returns a boolean value, so this operator returns a boolean operator.

E1 !>> E2

yields the same result as

!(E1 >> E2)

Example:

!("test" >> "st") == ("test" !>> "st")

Result:

true