The map-entry? predicate was just committed to master and will be in the next build.
On Friday, October 16, 2015 at 1:29:21 PM UTC-5, Mike Rodriguez wrote: > > Yes a `map-entry?` predicate was sort of the direction I was leaning in > that would help avoid issues like this around these changes. > > On Friday, October 16, 2015 at 10:58:47 AM UTC-5, Alex Miller wrote: >> >> Perhaps having a "map-entry?" predicate that was smarter would be helpful. >> >> On Friday, October 16, 2015 at 9:39:09 AM UTC-5, Mike Rodriguez wrote: >>> >>> Yes, I am in support of the fact that size=2 vectors now can now have >>> `key` and `val` called on them. This not working prior to Clojure 1.8 was >>> occasionally the reason why I just used `first` and `second` instead of >>> `key` and `val` before since some function transformations could result in >>> size=2 vectors rather than true map entries. >>> >>> I think that supporting `empty` on MapEntry is weird, as Alex said >>> above. It does sound the same as the record case. >>> >>> The only frustration I have with this change is that not all >>> APersistentVectors really act as a map entry. Only those of size=2 do. So >>> the interface becomes misleading if you try to use it to figure out from a >>> generic standpoint, what things are map entries and what things aren't. >>> The ambiguity is that all vectors look like map entries. I guess you >>> could do the >>> (instance? IMapEntry x) check along with (== 2 (count x)) for the vector >>> case... >>> >>> On Friday, October 16, 2015 at 6:39:50 AM UTC-5, Alex Miller wrote: >>>> >>>> >>>> On Friday, October 16, 2015 at 3:32:43 AM UTC-5, Pierre-Yves Ritschard >>>> wrote: >>>>> >>>>> Hi Mike, >>>>> >>>>> The code at here seems to contradict you: >>>>> >>>>> https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/APersistentVector.java#L448-L460, >>>>> >>>>> >>>>> as does "(key [:a :b])" in the REPL. >>>>> >>>>> The only limitation is that vectors need to be of size two to act as >>>>> IMapEntries (otherwise an IllegalOperation exception is thrown). >>>>> >>>>> The change seems logical and allows key & val to be used more >>>>> generically. >>>>> >>>>> You're right that will fail on code that checks for (instance? >>>>> IMapEntry). >>>>> >>>> >>>> APersistentVector implements IMapEntry, so this doesn't seem correct. >>>> >>>> >>>>> A good alternative - paging Alex Miller - could be for (empty) on a >>>>> MapEntry to return an empty PersistentVector instead of nil, which >>>>> would >>>>> ensure that calls to (into (empty <map-entry>) (map f <map-entry>)) >>>>> would return a valid map entry (instead of a collection). >>>>> >>>> >>>> It does not make sense to me for empty on a MapEntry to do what you ask >>>> (for similar reasons why empty on a record is not allowed). >>>> >>>> >>>>> I'm happy to create a ticket for this use-case if deemed valid. >>>>> >>>>> Cheers, >>>>> - pyr >>>>> >>>>> >>>>> >>>>> On 10/16/2015 01:28 AM, Mike Rodriguez wrote: >>>>> > Someone else looked at the issue on >>>>> https://github.com/ztellman/riddley/issues/18 >>>>> > >>>>> > This issue makes the current version of riddley, and therefore >>>>> potemkin, not work on Clojure 1.8 beta1 >>>>> > >>>>> > There is a pull request to fix it at >>>>> https://github.com/ztellman/riddley/pull/19 >>>>> > >>>>> > However I am wondering if it is going to affect more places. The >>>>> problem is that in Clojuee 1.8 APersistentVector now implements IMapEntry >>>>> (therefore j.u.Map$Entry as well), but it doesn't implement the key or >>>>> val >>>>> methods. >>>>> > What is the reason for that change and/or is this a desired side >>>>> effect of the change? >>>>> > >>>>> >>>> -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
