But a Maybe/Nothing will short-circuit the whole flow where cond-let won't?
On Thursday, 4 October 2018 08:38:05 UTC-7, Moe Aboulkheir wrote: > > 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.t...@gmail.com > <javascript:>> 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.en...@gmail.com >> <javascript:>> 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...@gmail.com >>> <javascript:>> 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 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 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 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.
