Moving to chat, to attempt to reduce the number of people I am annoying. On Wed, Feb 20, 2013 at 5:27 PM, William Tanksley, Jr <[email protected]> wrote: > Raul Miller <[email protected]> wrote: >> How is treating the "purely functional" case as having an element of >> unreality the same as the idea that closures (in a stateful context) >> are purely functional? > > If your definitions have "an element of unreality" they are incomplete > definitions. Unreality is not part of a definition. (Nor is unreality > the function of the subjunctive.)
"The subjunctive is a grammatical mood found in many languages. Subjunctive forms of verbs are typically used to express various states of unreality such as wish, emotion, possibility, judgment, opinion, necessity, or action that has not yet occurred – the precise situations in which they are used vary from language to language. The subjunctive is an irrealis mood (one that does not refer directly to what is necessarily real) – it is often contrasted with the indicative, which is a realis mood." > If you think closures CAN be used in a functional language, then by > your definition you think a functional language with closures wouldn't > allow mutable state, and that's what Boyko said. If you think closures > cannot be used in a functional language, you haven't said anything to > hint at it -- unless disagreeing with Boyko was how you hinted at it. I am currently thinking of purely functional programming languages as constraining operations so that "state" can be ignored. So I'd say your first sentence in this paragraph best matches my point of view. > Now, here's an interesting fact... Although some amazing people are > using J to build dynamic functions, J is a descendant of a language > called "FP" (invented by Backus) for which building dynamic functions > was specifically disallowed. I suspect that this is the reason for > some of J's restrictions on what sort of things you can return from a > function. J has an interesting path ahead of it now! We can balance > things out so that functions can return functions, in which case we > can argue about closures; or we can take J back down the FP road, > without closures. (Or we can stay on the same path we're on. I hope we > do either of the three choices with our eyes open.) That's a bit abbreviated, but that influence does exist. > In FP, they call a verb a "function" and an adverb a "functional". In J, neither term is used, and perhaps for good reason. > No, that has nothing to do with our discussion. Except one thing: > closures are impossible in a function-level language. I'm not sure about that, at the moment there's too much ambiguous about the conversation for me to know for sure. Thanks, -- Raul ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
