I'd say every and other methods like that should take another argument that specifies the number if times to test.
You could say that every returns: - true if the generator is finite and the function always returned true - false if one of the finite (either because the generator is or because a number was given as argument) number of calls of the function returned false - undefined if the generator is infinite and none of the finite number of calls returned false OR return a generator that tests a new value and returns either true or false every time it is called on the nth call, it tests n values map and filter clearly would be very useful. I'm not sure about the others. On Sat, Feb 4, 2012 at 10:06 PM, Michael A. Smith <mich...@smith-li.com> wrote: > Sorry for the resend. Meant to include the list. > > I like this idea a lot! However, what would be the correct behavior of > a method like 'every' on an infinite generator? > > -Michael A. Smith > > > > On Fri, Feb 3, 2012 at 3:54 PM, Domenic Denicola > <dome...@domenicdenicola.com> wrote: >> ES5's existing array extras make working with arrays a joy. >> >> However, sometimes arrays are not the right tool for the job. Perhaps you >> want lazy evaluation semantics (generators). Or perhaps you want to >> communicate that the list is immutable (compare .NET's `IEnumerable<T>` or >> Java's `Iterable<T>`). ES Harmony seems to have the answer: iterators! Like >> `IEnumerable<T>` or `Iterable<T>`, they are the most basic primitive of >> iteration. Yay! >> >> But, if my `fetchAllProducts()` method returns an iterator, I don't get my >> array extras. Sad. >> >> --- >> >> This may be solvable in library-space, but the iterator proposal doesn't >> seem to have an Iterator.prototype I could extend. So we end up with >> unfortunate underscore-style wrappers: >> >> _(iterator).chain().map(mapper).some(predicate).value() >> _.some(_.map(iterator, mapper), predicate) >> >> I propose adding the array extras to any iterator (in some way), such that >> we can have syntax similar to the following: >> >> iterator.map(mapper).some(predicate) // returns an iterator >> >> The methods I would like to see are: >> * every, filter, forEach, map, reduce, reduceRight, some >> * Optionally: join, toString >> * Controversially: sorted, reversed (non-mutating versions of sort and >> reverse) >> >> What do you think? >> >> -Domenic >> _______________________________________________ >> es-discuss mailing list >> es-discuss@mozilla.org >> https://mail.mozilla.org/listinfo/es-discuss >> > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss _______________________________________________ es-discuss mailing list es-discuss@mozilla.org https://mail.mozilla.org/listinfo/es-discuss
