3 ms·

Still being an absolute beginner at lispy syntax, I'll have to ask you the same question though. While I see the awesomeness in threading macros, I'm usually l

• klibertp 9y ago
  I thought it's a simple mnemonic: -> means inserting the form just after the beginning of the next one, while ->> inserts at the end of it. You most certainly can have explicit variable to thread through expressions, like this: (it-> (form1 it) (form2 3 it 4) ...) where it means "previous expression". I think there's a Clojure library which already implements this. You can use that if you want.
  • serpix 9y ago
    in Clojure this is achieved with `as->`
    • baldfat 9y ago
      In Racket we actually have a threading macro with ~> This: (- (bytes-ref (string->bytes/utf-8 (symbol->string 'abc)) 1) 2) Becomes this: (~> 'abc symbol->string string->bytes/utf-8 (bytes-ref 1) (- 2)) https://docs.racket-lang.org/threading/index.html https://docs.racket-lang.org/threading/index.html
      • peatmoss 9y ago
        I believe the use of "~>" rather than "->" in Racket was set in #lang rackjure which adds in some of the Clojure syntax to Racket. Also amusing is their explanation: > For example the threading macros are ~> and ~>> (using ~ instead of -) because Racket already uses -> for contracts. Plus as Danny Yoo pointed out to me, ~ is more "thready". http://docs.racket-lang.org/rackjure/index.html#%28part._.Background_philosophy%29 http://docs.racket-lang.org/rackjure/index.html#%28part._.Ba... More thready indeed :-p
• alphapapa 9y ago
  Emacs 25 has thread-first and thread-last macros in subr-x.el.