See https://funcool.github.io/cats/latest/#mlet for something closer to home, in the monadic vein.
On Thu, Oct 4, 2018 at 4:10 PM Gary Trakhman <gary.trakh...@gmail.com> wrote: > These are all just sugar over monadic bind, right? > > Here's one way to do it in the ocaml alternate universe: > https://github.com/janestreet/ppx_let#syntactic-forms-and-actual-rewriting > > But it can be made to work for async or options or whatever, too. > > We can put the async helpers in the same bucket: > https://github.com/ztellman/manifold/blob/master/docs/deferred.md#let-flow > > The general idea is turning function application into something that looks > less nested. > > On Wed, Oct 3, 2018 at 10:22 PM Mark Engelberg <mark.engelb...@gmail.com> > wrote: > >> This looks like a case of "convergent evolution". >> >> Having the ability to do a :let in the middle of a cond feels like one of >> those things that *should* be in the core language, so if it's not in >> there, a bunch of people are naturally going to arrive at the same solution >> and make it happen in their own utility libraries. A bunch of us Clojure >> programmers from the early 1.0 days had been privately passing around and >> using a "cond that supports :let bindings" macro for years. The first time >> I saw the macro was in a blog post by Christophe Grand. I really hoped it >> would make it into Clojure proper -- other functional languages like Racket >> and F# support ways to bind local variables with "clearer, more linear >> code, that doesn't make a march for the right margin", as Howard Lewis Ship >> put it. But after several years had passed without any indication that >> CLJ-200 was ever going to be addressed, I eventually made the improved cond >> macro into a clojars library. >> >> walmartlabs' cond-let addresses the most important thing (let), which is >> the critical piece of functionality that feels like the most natural, >> needed addition to the language. better-cond's :let syntax is identical. >> But as us old-school Clojurians passed around the "better cond" macro over >> the years, it grew in functionality. So in better-cond, I included the >> other little improvements that had accumulated over time, which I had found >> useful. So better-cond also supports :when, :when-let, and :do (and will >> soon have :when-some). :let is the only piece that I felt really belonged >> in the core language's cond, and if CLJ-200 had made it into the core >> language, I would have been content to just use Clojure's own cond. But >> once I realized I was going to need a library to achieve the much-needed >> :let inside of cond, I figured I might as well use that library to include >> the other convenient cond additions as well. So better-cond is a superset >> of cond-let's functionality, with support for :let plus a few bonuses. >> >> Use whichever one strikes your fancy. cond-let is perfect if all you >> care about is adding :let to your cond. If you want to experiment with >> some of the other features beyond :let, you could use better-cond and see >> what you think. >> >> Either way, I strongly encourage you to use one of these two libraries so >> you can start using :let inside your cond. I agree fully with Howard Lewis >> Ship that it results in clearer code. Try either library which supports >> this -- it will change your life! >> >> >> On Wed, Oct 3, 2018 at 5:05 PM Matching Socks <phill.w...@gmail.com> >> wrote: >> >>> Is this a refinement of Mark Engelberg's "better-cond", or an >>> alternative approach? >>> >>> I have not used better-cond myself, but it starts here: >>> https://dev.clojure.org/jira/browse/CLJ-200. >>> >>> -- >>> 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. >> > -- > 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. 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