Got it. The macro, as is, will displace the print method for the same arity.
On Friday, April 25, 2014 2:50:34 PM UTC-7, Gary Trakhman wrote: > > Ah, I think I was mistaken in a detail, but generally correct. Try it > with two partials of the same arity. > > > https://github.com/clojure/clojure/blob/master/src/clj/clojure/core.clj#L2460 > > > On Fri, Apr 25, 2014 at 5:47 PM, Greg D <gregoir...@gmail.com<javascript:> > > wrote: > >> I guess I don't understand the problem, or what is meant by "different >> classes". A counter-example would be helpful. >> >> Further transcript using the macro: >> (def p6 (partial* + 1 2 3)) >> #'user/p6 >> user=> (class p6) >> clojure.core$partial$fn__4194 >> user=> (def p10 (partial* + 1 2 3 4)) >> #'user/p10 >> user=> (class p10) >> clojure.core$partial$fn__4196 >> >> user=> p6 >> (partial + 1 2 3) >> user=> p10 >> (partial + 1 2 3 4) >> user=> (p6 100) >> 106 >> user=> (p10 100) >> 110 >> >> On Friday, April 25, 2014 2:33:50 PM UTC-7, Gary Trakhman wrote: >> >>> That's not going to work, all the return classes of partial are the same >>> class. >>> >>> >>> On Fri, Apr 25, 2014 at 5:26 PM, Greg D <gregoir...@gmail.com> wrote: >>> >>>> I don't know if this is considered good Clojure, but you could define a >>>> print-method within a macro to set up the normal string representation for >>>> the partial function: >>>> (defmacro partial* [fname arg0 & args] >>>> `(let [pf# (partial ~fname ~arg0 ~@args) >>>> cpf# (class pf#)] >>>> (defmethod print-method cpf# [o# w#] >>>> (if (nil? '~args) >>>> (print-simple (str "(partial " '~fname " " (pr-str ~arg0) ")") >>>> w#) >>>> (print-simple (str "(partial " '~fname " " (pr-str ~arg0) >>>> ~@(map #(str " " (pr-str %)) args) ")") w#))) >>>> pf#)) >>>> >>>> A transcript of some quick examples: >>>> user=> (def p6 (partial* + 1 2 3)) >>>> #'user/p6 >>>> user=> p6 >>>> (partial + 1 2 3) >>>> user=> (p6 7) >>>> 13 >>>> user=> (def re-find-foo (partial* re-find #"foo")) >>>> #'user/re-find-foo >>>> user=> re-find-foo >>>> (partial re-find #"foo") >>>> user=> (re-find-foo "abcdefooghi") >>>> "foo" >>>> >>>> >>>> On Friday, April 25, 2014 9:01:37 AM UTC-7, Matthew DeVore wrote: >>>>> >>>>> Hi, >>>>> >>>>> There has been one thing bugging me for a long time that seems worth >>>>> it to fix, and I was wondering if anyone else has had the same problem. I >>>>> have enjoyed using Clojure's REPL and embracing a Clojure-style data >>>>> model >>>>> for my app, where everything is a glorified map or vector and there are >>>>> no >>>>> private fields. I even have a simple dump feature that tells me the >>>>> entire >>>>> state of my app <https://github.com/google/hesokuri> that was >>>>> ridiculously easy to implement, and that takes advantage of the lack of >>>>> black box data structures. >>>>> >>>>> One thing that doesn't really fit in this paradigm is (ironically) >>>>> anonymous functions with closures. For instance, (partial + 42) returns >>>>> an >>>>> anonymous function, and in the REPL or an app dump, it looks hideous: >>>>> #<core$partial$fn__4228 clojure.core$partial$fn__4228@1ee1dea2> >>>>> >>>>> So I've avoided anonymous functions in my app except when they exist >>>>> transiently, and don't appear in the dump (for instance, in (map #(str % >>>>> "!") foo)). But sometimes I just can't avoid a long-lived anonymous >>>>> function practically. The best solution I've come up with is to transform >>>>> anonymous functions when preparing the application dump. (See the >>>>> implementation<https://github.com/google/hesokuri/blob/b60cb7222cfdd672e394ef6f22b80c94278fe3a0/src/hesokuri/see.clj#L35>) >>>>> >>>>> This makes (partial + 42) look like this: >>>>> >>>>> {:fn-class clojure.core$partial$fn__4228, >>>>> "arg1" 42, >>>>> "f" {:fn-class clojure.core$_PLUS_}} >>>>> >>>>> Which isn't great (I'd like to have filenames and line numbers for >>>>> each anon fn, and a nicer name for clojure.core/+), but it's a big >>>>> improvement. The function's JVM class and the closured values are >>>>> revealed. >>>>> It would be nice to implement this natively. Having only passing >>>>> familiarity with the Clojure code base, to solve it I think one could: >>>>> >>>>> - give anonymous functions a .getClosure method which creates a >>>>> view of the closure on-demand >>>>> - (optional) change their .toString implementation to include this >>>>> information >>>>> - add logic to clojure.pprint to use the .getClosure method (I >>>>> guess "(defmethod clojure.pprint/simple-dispatch >>>>> clojure.lang.AFunction >>>>> etc...)" ?) >>>>> >>>>> Another feature that would go nicely with this is smarter equality >>>>> semantics for anonymous functions, so that any two anonymous functions >>>>> generated at the same point in code with equal closures are equal. This >>>>> means if I have a function like this: >>>>> >>>>> (defn exclaimer [bangs] #(apply str % (repeat bangs "!"))) >>>>> >>>>> then the following would be true: (= (exclaimer 10) (exclaimer 10)), >>>>> making functions behave a lot more like values. I would love to have this >>>>> particular feature too, although I'm having trouble coming up with a >>>>> non-contrived example. >>>>> >>>>> I'd like to hear some thoughts on this. Thanks! >>>>> >>>>> Matt >>>>> >>>>> >>>>> >>>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Clojure" group. >>>> To post to this group, send email to clo...@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+u...@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+u...@googlegroups.com. >>>> >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clo...@googlegroups.com<javascript:> >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+u...@googlegroups.com <javascript:> >> 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+u...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > -- 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.
