Re: Questions about some-fn and every-pred (possible bug, and improvements)
Thanks, perfect, I had prepared a patch that was identical. On Thursday, October 25, 2012 2:11:44 PM UTC+2, Tassilo Horn wrote: > > Tassilo Horn > writes: > > >>> user> ((some-fn) ) > >>> false > >>> user> ((every-pred) ) > >>> true > >>> > >>> e.g. (some-cn) was equivalent to (constantly false) and (every-pred) > was > >>> equivalent to (constantly true). > >> > >> Yes I understand that, the proposal was just to avoid exceptions when > >> used with apply, but this could end up be bit confusing maybe, and it > >> can be tested beforehand anyway. > > > > No, I think it's a valid request and it wouldn't be more confusing than > > (and) => true (or) => false. I'll create a ticket and patch for it. > > Done, see http://dev.clojure.org/jira/browse/CLJ-1094 > > In contrast to what's written above, I decided to make (some-fn) to be > (constantly nil), which matches the behavior of `some` better than > (constantly false). > > Bye, > Tassilo > -- 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
Re: Questions about some-fn and every-pred (possible bug, and improvements)
Tassilo Horn writes: >>> user> ((some-fn) ) >>> false >>> user> ((every-pred) ) >>> true >>> >>> e.g. (some-cn) was equivalent to (constantly false) and (every-pred) was >>> equivalent to (constantly true). >> >> Yes I understand that, the proposal was just to avoid exceptions when >> used with apply, but this could end up be bit confusing maybe, and it >> can be tested beforehand anyway. > > No, I think it's a valid request and it wouldn't be more confusing than > (and) => true (or) => false. I'll create a ticket and patch for it. Done, see http://dev.clojure.org/jira/browse/CLJ-1094 In contrast to what's written above, I decided to make (some-fn) to be (constantly nil), which matches the behavior of `some` better than (constantly false). Bye, Tassilo -- 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
Re: Questions about some-fn and every-pred (possible bug, and improvements)
Max Penet writes: Hi Max, >> user> ((some-fn) ) >> false >> user> ((every-pred) ) >> true >> >> e.g. (some-cn) was equivalent to (constantly false) and (every-pred) was >> equivalent to (constantly true). > > Yes I understand that, the proposal was just to avoid exceptions when > used with apply, but this could end up be bit confusing maybe, and it > can be tested beforehand anyway. No, I think it's a valid request and it wouldn't be more confusing than (and) => true (or) => false. I'll create a ticket and patch for it. Bye, Tassilo -- 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
Re: Questions about some-fn and every-pred (possible bug, and improvements)
On Thursday, October 25, 2012 12:49:32 PM UTC+2, Tassilo Horn wrote: > > Max Penet writes: > > > user> ((every-pred (fn [_]))) > > true > > user> ((some-fn (fn [_]))) > > nil > > > > Shouldn't the first example return false? since the first function > > always returns nil? > > No. ((every-pred a b c) o1 o2 ...) returns true if all predicates a, b, > and c return true for all given args o1, o2, and so one. You don't pass > any args, so this is basically (and), which also returns true. `and` is > true if all arguments are logically true, which is trivially given when > none are provided. > Ok that makes sense. > > > I was also wondering if it would make sense to add a 0 argument > > version of these, it would make their usage with apply more > > convenient, and comp which has a smiliar signature behaves like that: > > > > user> ((comp) true) > > true > > > > user> ((some-fn) true) > > ; Evaluation aborted. > > > > user> ((every-pred) true) > > ; Evaluation aborted. > > (comp) is `identity` which makes sense. What would the semantics be for > every-pred and some-fn? IMO, it should be > > user> ((some-fn) ) > false > user> ((every-pred) ) > true > > e.g. (some-cn) was equivalent to (constantly false) and (every-pred) was > equivalent to (constantly true). > Yes I understand that, the proposal was just to avoid exceptions when used with apply, but this could end up be bit confusing maybe, and it can be tested beforehand anyway. Max -- 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
Re: Questions about some-fn and every-pred (possible bug, and improvements)
user> (every? identity []) true I think I understand now, this might be to match the behavior of "every?". Max On Thursday, October 25, 2012 12:31:57 PM UTC+2, Max Penet wrote: > > Hello, > > I am trying to understand the rationale behind the current implementation > of some-fn and every-pred, there seems to be a couple of odd things, or > maybe that is just me misunderstanding their doc. > > user> ((every-pred (fn [_]))) > true > user> ((some-fn (fn [_]))) > nil > > Shouldn't the first example return false? since the first function always > returns nil? > > I was also wondering if it would make sense to add a 0 argument version of > these, it would make their usage with apply more convenient, and comp which > has a smiliar signature behaves like that: > > user> ((comp) true) > true > > user> ((some-fn) true) > ; Evaluation aborted. > > user> ((every-pred) true) > ; Evaluation aborted. > > Max > -- 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
Re: Questions about some-fn and every-pred (possible bug, and improvements)
Max Penet writes: > user> ((every-pred (fn [_]))) > true > user> ((some-fn (fn [_]))) > nil > > Shouldn't the first example return false? since the first function > always returns nil? No. ((every-pred a b c) o1 o2 ...) returns true if all predicates a, b, and c return true for all given args o1, o2, and so one. You don't pass any args, so this is basically (and), which also returns true. `and` is true if all arguments are logically true, which is trivially given when none are provided. > I was also wondering if it would make sense to add a 0 argument > version of these, it would make their usage with apply more > convenient, and comp which has a smiliar signature behaves like that: > > user> ((comp) true) > true > > user> ((some-fn) true) > ; Evaluation aborted. > > user> ((every-pred) true) > ; Evaluation aborted. (comp) is `identity` which makes sense. What would the semantics be for every-pred and some-fn? IMO, it should be user> ((some-fn) ) false user> ((every-pred) ) true e.g. (some-cn) was equivalent to (constantly false) and (every-pred) was equivalent to (constantly true). Bye, Tassilo -- 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
Questions about some-fn and every-pred (possible bug, and improvements)
Hello, I am trying to understand the rationale behind the current implementation of some-fn and every-pred, there seems to be a couple of odd things, or maybe that is just me misunderstanding their doc. user> ((every-pred (fn [_]))) true user> ((some-fn (fn [_]))) nil Shouldn't the first example return false? since the first function always returns nil? I was also wondering if it would make sense to add a 0 argument version of these, it would make their usage with apply more convenient, and comp which has a smiliar signature behaves like that: user> ((comp) true) true user> ((some-fn) true) ; Evaluation aborted. user> ((every-pred) true) ; Evaluation aborted. Max -- 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
