Talk:Closure (computer programming): Difference between revisions

Revision as of 22:00, 28 December 2011

Revision as of 22:52, 28 December 2011

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:"''In computer science, a closure (also lexical closure, function closure, function value or functional value) is a function together with a referencing environment for the non-local variables of that function.''" This sentence is by far the most confusing thing I've ever seen. I'm almost on the floor laughing from how vaguely confusing it is. Firstly the usage of "together with" in this sentence is nothing more than weasel words here and add insult to injury in this confusing context. I see what you guys are trying to do here by trying to define a closure in one sentence but we shouldn't be tossing around confusing words like that before the end-user at least knows what we are talking about. If anything, I think it would be best if we flipped some things around in this sentence. Can we re-word the sentence to something more like this?: ''In computer science, a closure (also lexical closure, function closure, function value or functional value) is the scope of a function that that has a referencing environment for variables which are not local to it that appear in a parent, and in most cases not global, scope.'' --[[User:Thelazyleo|<span style="color:blue;">T<span style="color:royalblue">he</span>l<span style="color:royalblue">azy</span>l<span style="color:royalblue">eo</span></span>]] ([[User talk:Thelazyleo|<span>talk</span>]]) 20:39, 28 December 2011 (UTC)

:: In my opinion your suggestion is more confusing and less accurate than the current wording. Operationally, a closure is a data structure pairing a function (reference/pointer) with ana table (the referencing environment). See for example the definition by Sussman and Steele given in the first footnote. This is a fairly unambiguous and precise definition (given that you know what a referencing environment is, what necessarily has the be explained in the following sentences.) Your proposed definition on the other hand uses the rather vague and imprecise "a closure ... is the scope of a function". Semantically, a closure has everything to do with scoping, of course, but this is what the sentences following the first try to explain. I therefore think it's only useful to whole first paragraph, not just the first sentence. —''[[User:Ruud Koot|Ruud]]'' 21:45, 28 December 2011 (UTC)

:: I do think that the final part of the first sentence ("for the non-local variables of that function.") needs to be clarified. In particular it might be possible to give a definition of "referencing environment" instead. Something along the lines of "a map containing [[name binding|binding]]s for the [[non-local variable]]s of that function."?—''[[User:Ruud Koot|Ruud]]'' 21:47, 28 December 2011 (UTC)