Scheme Programming Language


	If blocks Can someone explain to me the proper way to code an 'if' statement when there are multiple lines involved. For instance in Ruby: if x == true do_step_one() do_step_two() else do_step_three() do_step_four() end How is this properly done on Scheme: (if (eqv? x #t) (if (eqv? x #t) (begin ((do-step-one) (do-step- one) (do-step-two)) (do-step-two)) or ((do-step-three) (begin (do-step-four))) (do-step-three) (do-step-four))) Is begin the way to go or does begin have a different (sequencing) meaning? And is the other way even legal? WoodHacker wrote: > Can someone explain to me the proper way to code an 'if' statement > when there are multiple lines involved. > For instance in Ruby: > if x == true > do_step_one() > do_step_two() > else > do_step_three() > do_step_four() > end (cond [x (do-step-one) (do-step-two)] [else (do-step-three) (do-step-four)]) > Is begin the way to go or does begin have a different (sequencing) > meaning? With if+begin it looks like: (if x (begin (step1) (step2)) (begin (step3) (step4))) but I find that harder to read. -- Jens Axel Sgaard On Apr 6, 8:03 am, Jens Axel Sgaard <use@soegaard.net> wrote: - Hide quoted text - > WoodHacker wrote: > > Can someone explain to me the proper way to code an 'if' statement > > when there are multiple lines involved. > > For instance in Ruby: > > if x == true > > do_step_one() > > do_step_two() > > else > > do_step_three() > > do_step_four() > > end > (cond > [x (do-step-one) > (do-step-two)] > [else > (do-step-three) > (do-step-four)]) > > Is begin the way to go or does begin have a different (sequencing) > > meaning? > With if+begin it looks like: > (if x > (begin > (step1) > (step2)) > (begin > (step3) > (step4))) > but I find that harder to read. > -- > Jens Axel Sgaard Brackets apparently don't work in Chicken Scheme, which is what I'm using. It compiles, but I get errors when I run it. Using cond seems overkill for such a simple conditional, but it's probably just as efficient. Thanks for the help. Bill In article <1175949270.113445.280@y80g2000hsf.googlegroups.com>, "WoodHacker" <ramsa@comcast.net> wrote: > On Apr 6, 8:03 am, Jens Axel Sgaard <use@soegaard.net> wrote: <snip> > Brackets apparently don't work in Chicken Scheme, which is what I'm > using. It compiles, but I get errors when I run it. Using cond > seems overkill for such a simple conditional, but it's probably just > as efficient. Thanks for the help. > Bill What version of Chicken? I think brackets, '[...]', have been legal syntax since before version 2 (2 years ago). If you see errors then something else besides syntax is the problem. cond is usually compiled into nested if forms anyway so efficiency is more of a programmer time rather than a machine time issue. Try the Chicken mailing list, chicken-us@nongnu.org, for Chicken specific questions. Best Wishes, Kon

Scheme Programming Language

If blocks