On Tue, Feb 10, 2009 at 5:02 PM, MattH <mbhut...@gmail.com> wrote: > > The pipe macro is definitely not a new idea btw. It's taken from a > thread posted on another lisp group. > > Someone posted a silly inflammatory attack on lisp, contrasting unix: > "cat a b c | grep xyz | sort | uniq" > to how they'd imagine it in lisp: > "(uniq (sort (grep xyz (cat a b c))))" > > A poster called Edward retorted: > " > (pipe (cat a b c) (grep xyz) (sort) (uniq)) > 'Nuff said. > " > > Here's the link, but *not* recommend reading :) > > http://groups.google.com/group/comp.lang.lisp/browse_thread/thread/d0ce288e1cd22654/cc25683874ecc457 > > When watching the Abelson and Sussman (SICP) lectures online, when > Abelson was using map/filter/reduce etc, he would sometimes explain > the code from the inside out, pointing to the most inner part, then > working outwards and up. > > I get the same cognitive overload on seeing lots of nesting. Expanding > out onto multiple lines helps, but you still hit a wall. > > (transform-g > (transform-f > ... > (transform-b) > (transform-a) > (some-generator)))))))) > > vs > > (pipe > (some-generator) > (transform-a) > (transform-b) > ... > (transform-f) > (transform-g) > ) > > The nested form would tell me "it's time to generalise and write a new > function". But if using the pipe form I'd happily expand and edit the > chain of transforms. It's pretty easy to swap parts of the chain, or > disable transforms by commenting them out. > > The let-> form is really interesting and a nice implementation - > pretty amazing to see solution to the general case so quickly. I have > the same reservation about using it though, I wouldn't want "x" to > mean something different in the same lexical scope. Maybe it's just a > case of finding a good name for "x"? Something like "the-evaluation-of- > the-previous-form", but shorter..
Maybe _ is appropriate? => (let-> _ (+ 1 2) (* 2 _) (+ _ 1)) 7 => (let-> _ [1 2 3] (map inc _) (reduce + _) (+ _ 3)) 12 Or maybe ? ? /mike. --~--~---------~--~----~------------~-------~--~----~ 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 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 -~----------~----~----~----~------~----~------~--~---
