I think there's generally a UI/UX notion of "declarative", the "declarative feel". There's also that whole list of technical definitions. The mismatch is one of

I think there's generally a UI/UX notion of "declarative", the "declarative feel". There's also that whole list of technical definitions. The mismatch is one of category as much as of definition. For instance, I would analyze your foldl example as being driven by the fact that foldl has a denotation above its implementation. But, as Harper notes, all languages have a denotational semantics if we choose to recognize them and it's difficult to say what it means for a denotational semantics ti be "better" than another in any technical sense. So what is declarative? In my mind, it should really only be a UX term. I think technical definitions are debated because of the category mismatch alluded to earlier. I think notions like "equational semantics", "denotational semantics", "referentially transparent", and "variable" are the right technical terminology.