I think that's right. The "closure" is a function, it is not called until method #ifTrue: of the boolean value in question gets it as argument. But it is not j

I think that's right. The "closure" is a function, it is not called until method #ifTrue: of the boolean value in question gets it as argument. But it is not just "a function", it is a "closure" meaning it carries with it values from its outer scope that were there at the time the #ifTrue: -method was called, which includes arguments to the outer method being called.