That library and others like it (e.g., oh, I dunno, babbage) impose more overhead, though, than a simple let form, if you just want to use something one-off in one place.
On Sat, Apr 27, 2013 at 5:05 PM, Alan Busby <thebu...@thebusby.com> wrote: > Hi All, > > You may want to take a look at Prismatic's graph library, it does what > you've described above in a slightly different way. > Link: https://github.com/Prismatic/plumbing > > > On Sun, Apr 28, 2013 at 1:04 AM, Ben Wolfson <wolf...@gmail.com> wrote: > >> It's not too hard, though, to write a plet form that first does some >> analysis on the bindings to see which of them depend on which others. I >> believe I mentioned this elsewhere in the group as an example of why a >> macro might want to macroexpand its arguments, because doing that is the >> simplest way to find out where you've got a binding form. In: >> >> (plet [a 2 b (my-mystery-macro [a 5] a)] b) >> >> if my-mystery-macro introduces a binding for 'a', then the expressions >> can be evaluated in parallel, since 'a' isn't free in the expression being >> bound to 'b'; otherwise, 'a' *is* free in that expression and refers to the >> earlier binding, and the two expressions can't be evaluated in parallel. >> >> >> >> On Sat, Apr 27, 2013 at 8:59 AM, Ben Wolfson <wolf...@gmail.com> wrote: >> >>> "guv" is broken if your let form introduces bindings that depend on >>> earlier bindings: >>> >>> user=> (plet [a 2 b a] b) >>> CompilerException java.lang.RuntimeException: Unable to resolve symbol: >>> a in this context, compiling:(NO_SOURCE_PATH:1) >>> >>> user=> (clojure.pprint/pprint (macroexpand-1 '(plet [a 2 b a] b))) >>> (clojure.core/let >>> [G__364 >>> (clojure.core/future 2) >>> G__365 >>> (clojure.core/future a) ;;; oops! >>> a >>> @G__364 >>> b >>> @G__365] >>> b) >>> nil >>> user=> >>> >>> In fact, both of them are broken in this way. >>> >>> >>> >>> On Sat, Apr 27, 2013 at 6:55 AM, Glen Mailer <glenja...@gmail.com>wrote: >>> >>>> Hi All, >>>> >>>> I was recently looking at how to make better use of parallelisation for >>>> simple tasks in my compojure app, I had a construction similar to the >>>> following: >>>> >>>> (views/some-view (api/api-call-1) (api/api-call-2) (api/api-call-3)) >>>> >>>> It seemed that the easiest way to introduce some parallelism here would >>>> be in the style of a let form: >>>> >>>> (let [result-1 (api/api-call-1) >>>> result-2 (api/api-call-2) >>>> result-3 (api/api-call-3)] >>>> (views/some-view result-1 result-2 result-3) >>>> >>>> There doesn't appear to be anything in core that does, this - after a >>>> brief discussion in the IRC channel, I received the following two >>>> suggestions: https://gist.github.com/jcromartie/5459350 and >>>> https://gist.github.com/guv/5459364 >>>> >>>> I ended up going with the approach from "guv", as I understood it >>>> better - and I moved the let form inside the view function to cut down on >>>> the repetition a bit. >>>> >>>> Now, to my actual questions: >>>> >>>> What are the differences between the pmap approach and the futures >>>> approach? >>>> >>>> And would a construction like this be useful in core? If so, how does >>>> it potentially get there? >>>> >>>> >>>> Thanks >>>> Glen Mailer >>>> Budding Clojurer >>>> >>>> >>>> -- >>>> -- >>>> 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/groups/opt_out. >>>> >>>> >>>> >>> >>> >>> >>> -- >>> Ben Wolfson >>> "Human kind has used its intelligence to vary the flavour of drinks, >>> which may be sweet, aromatic, fermented or spirit-based. ... Family and >>> social life also offer numerous other occasions to consume drinks for >>> pleasure." [Larousse, "Drink" entry] >>> >>> >> >> >> -- >> Ben Wolfson >> "Human kind has used its intelligence to vary the flavour of drinks, >> which may be sweet, aromatic, fermented or spirit-based. ... Family and >> social life also offer numerous other occasions to consume drinks for >> pleasure." [Larousse, "Drink" entry] >> >> -- >> -- >> 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/groups/opt_out. >> >> >> > > -- > -- > 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/groups/opt_out. > > > -- Ben Wolfson "Human kind has used its intelligence to vary the flavour of drinks, which may be sweet, aromatic, fermented or spirit-based. ... Family and social life also offer numerous other occasions to consume drinks for pleasure." [Larousse, "Drink" entry] -- -- 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/groups/opt_out.
