Re: [racket] Looking for better designs to learn principles.

Ah, I should've said that performance is not ideal with either compose (or thrush), since they build the entire e.g. 10 million long function chain before calling it, so tail-recursive variants below (define (iterate f n x) (for/fold ([x x]) ([i n]) (f x))) or with the thread-th

Re: [racket] Looking for better designs to learn principles.

There’s also the thrush function from the point-free package, which uses the argument order of the threading macro while providing the functional style of compose. http://pkg-build.racket-lang.org/doc/point-free/index.html?q=thrush#%28def._%28%28lib._point-free%2Fmain..rkt%29._thrush%29%29

Re: [racket] Looking for better designs to learn principles.

If "thread-through macro" refers to " http://www.greghendershott.com/2013/05/the-threading-macro.html"; then I recommend a functional alternative called "compose": (define print/cdr (match-lambda [(cons x xs) (print x) xs])) (define print-two (compose print/cdr print/cdr)) The result is

Re: [racket] Looking for better designs to learn principles.

How about (define print-two (match-lambda [(list* a b rest) (print a) (print b) rest])) ? On 03/12/2015 06:25 PM, Don Green wrote: > ;Design A: > ;Rating: 1 out of 10 > ;Poor because it uses set! > (define print-two > (lambda (f) >(print (first f)) >(set! f (rest f

Re: [racket] Looking for better designs to learn principles.

racket-lang.org] On Behalf Of Don Green Sent: jueves, 12 de marzo de 2015 19:25 To: users@racket-lang.org Subject: [racket] Looking for better designs to learn principles. ;Design A: ;Rating: 1 out of 10 ;Poor because it uses set! (define print-two (lambda (f) (print (first f))

[racket] Looking for better designs to learn principles.

;Design A: ;Rating: 1 out of 10 ;Poor because it uses set! (define print-two (lambda (f) (print (first f)) (set! f (rest f)) (print (first f)) (set! f (rest f)) f)) (void (print-two '(1 2))) ;=> 12 ;- ;Design B: ;Rating: 2 out of 10 ;Better because it nests