Sorry, but this use of intern is a pointless. What does intern give you that a let over a defn doesn't?
On Sat, May 13, 2017 at 4:37 PM, Alan Thompson <clooj...@gmail.com> wrote: > If anyone is interested, I cleaned up the question to (hopefully) make it > clearer, as well as adding the macro-calling-a-macro solution. > > While some may consider it esoteric, I thought it was a good example of > the power `intern` can provide, as well as a good way to avoid macros and > stick to pure functions. > > Here is the re-worked version: http://stackoverflow.com/ > questions/43958471/how-to-create-clojure-defn-functions- > automatically-without-macros/ > > Alan > > On Thu, May 11, 2017 at 10:15 AM, Alan Thompson <clooj...@gmail.com> > wrote: > >> Actually someone else wrote the original CLJS question (1): >> http://stackoverflow.com/questions/43897632/mapped-calls- >> to-clojurescript-macro >> >> It was marked as a duplicate of this question (2): >> http://stackoverflow.com/questions/43897632/mapped-calls- >> to-clojurescript-macro This one also had an answer using `intern` to >> avoid the need for a macro. >> >> I didn't think question (1) was an exact duplicate of (2), and I wanted >> to work out the details of solving (1) using `intern` instead of macros (it >> seemed like a good goal at the time...). I tried to simplify question (1) >> w/o the CLJS callback stuff, and may have oversimplified. >> >> Since question was closed as being a "duplicate" (in error, I think), I >> couldn't answer there and posed the Q&A style answer separately at (3): >> http://stackoverflow.com/questions/43904628/how-to-create- >> clojure-defn-functions-automatically >> >> The main goal I had here was simply finding a good way to avoid macros >> when auto-generating functions, and to generalize/document the technique >> described in (2) using `intern`. >> >> Alan >> >> P.S. Regarding (3), Joel Spolsky, creator of StackOverflow, has often >> encouraged people to post both a question and its answer on the site: >> https://stackoverflow.blog/2011/07/01/its-ok-to-ask-and-ans >> wer-your-own-questions In fact, they even have a special button for >> this purpose. >> >> >> >> On Thu, May 11, 2017 at 9:39 AM, Timothy Baldridge <tbaldri...@gmail.com> >> wrote: >> >>> I assume this is a real problem you are encountering since you wrote the >>> original Stack Overflow questions. As Dragan mentioned, this example >>> doesn't warrant such a complex solution, maps and keywords *are* function, >>> so all you really need is `foo` as a getter. Or even if they weren't >>> functions you still have `(partial get foo)`. >>> >>> On Thu, May 11, 2017 at 10:27 AM, Alan Thompson <clooj...@gmail.com> >>> wrote: >>> >>>> Since the original question was in CLJS, which has neither `intern` nor >>>> `eval`, does that mean the macro mapping another macro approach is the only >>>> solution there? >>>> >>>> >>>> On Thu, May 11, 2017 at 9:18 AM, Alan Thompson <clooj...@gmail.com> >>>> wrote: >>>> >>>>> I like the idea of using `eval` and `memoize`. I'll have to keep >>>>> that in mind. >>>>> Alan >>>>> >>>>> On Thu, May 11, 2017 at 7:58 AM, Timothy Baldridge < >>>>> tbaldri...@gmail.com> wrote: >>>>> >>>>>> This is a somewhat weird answer to a overcomplicated problem. As >>>>>> mentioned, the data is a map to start with, and maps are functions so >>>>>> treating the maps as data is probably the best approach. And like Dragan, >>>>>> I'm unsure why this example doesn't use `(data :able)`. >>>>>> >>>>>> When I do need to generate functions at runtime, and I can't use >>>>>> macros (for the reasons mentioned), I'll either use a macro that creates >>>>>> a >>>>>> var, or use eval perhaps in conjunction with a memoize. I used this a lot >>>>>> in my work with JavaFx. Do some reflection, generate some code, eval the >>>>>> code and return a function, memoize that process so we can get the >>>>>> generated function via name. So the interface looks like this: >>>>>> >>>>>> ((get-setter button :text) "hey") >>>>>> >>>>>> Get-setter does a ton of reflection, but calling the returned >>>>>> function remains fast due to the combination of eval and memoization. >>>>>> >>>>>> >>>>>> >>>>>> On Thu, May 11, 2017 at 2:55 AM, Dragan Djuric <draga...@gmail.com> >>>>>> wrote: >>>>>> >>>>>>> What's wrong with (foo :able) => "Adelicious!" and (:able foo) => >>>>>>> "Adelicious!"? >>>>>>> >>>>>>> >>>>>>> On Thursday, May 11, 2017 at 9:20:19 AM UTC+2, Alan Thompson wrote: >>>>>>>> >>>>>>>> A recent question on StackOverflow raised the question of the best >>>>>>>> way to automatically generate functions. Suppose you want to automate >>>>>>>> the >>>>>>>> creation of code like this: >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> (def foo >>>>>>>> {:able "Adelicious!" >>>>>>>> :baker "Barbrallicious!" >>>>>>>> :charlie "Charlizable"}) >>>>>>>> (def bar >>>>>>>> {:able "Apple" >>>>>>>> :baker "Berry" >>>>>>>> :charlie "Kumquat"}) >>>>>>>> >>>>>>>> (defn manual-my-foo [item] (get foo item)) >>>>>>>> (defn manual-my-bar [item] (get bar item)) >>>>>>>> >>>>>>>> (manual-my-foo :able) => "Adelicious!" >>>>>>>> (manual-my-bar :charlie) => "Kumquat" >>>>>>>> >>>>>>>> >>>>>>>> You could write a macro to generate one of these at a time, but you >>>>>>>> can't pass a macro to a higher-order function like `map`, so while this >>>>>>>> would work: >>>>>>>> >>>>>>>> >>>>>>>> (generate-fn :foo) ;=> creates `my-foo` w/o hand-writing it >>>>>>>> >>>>>>>> >>>>>>>> this wouldn't work: >>>>>>>> >>>>>>>> >>>>>>>> (map generate-fn [:foo :bar :baz]) >>>>>>>> >>>>>>>> While one could write a 2nd macro to replace `map`, this is a >>>>>>>> symptom of the "Turtles All the Way Down" problem. One workaround is to >>>>>>>> avoid macros altogether and use only functions to generate the required >>>>>>>> `my-foo` and `my-bar` functions. The trick is to make use of the >>>>>>>> built-in >>>>>>>> Clojure function `intern` both to save the newly generated functions >>>>>>>> into >>>>>>>> the global environment and to retrieve the pre-existing maps `foo` and >>>>>>>> `bar`. Full details are available Q&A-style at the StackOverflow >>>>>>>> post >>>>>>>> <http://stackoverflow.com/questions/43904628/how-to-create-clojure-defn-functions-automatically/43904717#43904717> >>>>>>>> . >>>>>>>> >>>>>>>> Enjoy, >>>>>>>> Alan >>>>>>>> >>>>>>>> -- >>>>>>> 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. >>>>>>> >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> “One of the main causes of the fall of the Roman Empire was >>>>>> that–lacking zero–they had no way to indicate successful termination of >>>>>> their C programs.” >>>>>> (Robert Firth) >>>>>> >>>>>> -- >>>>>> 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. >>>>>> >>>>> >>>>> >>>> -- >>>> 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. >>>> >>> >>> >>> >>> -- >>> “One of the main causes of the fall of the Roman Empire was that–lacking >>> zero–they had no way to indicate successful termination of their C >>> programs.” >>> (Robert Firth) >>> >>> -- >>> 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. >>> >> >> > -- > 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. > -- “One of the main causes of the fall of the Roman Empire was that–lacking zero–they had no way to indicate successful termination of their C programs.” (Robert Firth) -- You received this message because you are subscribed to the Google Groups "Clojure" group. 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