reading/onlisp/chapter4.clj @@ -1,9 +1,13 @@ +; Chapter 3 was a relatively short chapter (code-wise). It dealt mostly with side-effects and the virtues of a more functional style to avoid such evil. Thankfully, Clojure eliminates many of the problems outlined by Graham in the way that it prefers immutability and minimizes the functions causing side-effects. + ; pg. 29 -(comment - Graham provides a bad implementation of a reverse function that modifies a list in place. To do this in Clojure would require some gymnastics and - therefore is probably not worth the effort.) + +; Graham provides an intentionally bad implementation of a reverse function that modifies a list in place. To do this in Clojure would require some gymnastics and therefore is probably not worth the effort. ; pg. 30 + +;<pre lang="lisp"> + (defn good-reverse [lst] (defn rev [lst acc] (if (nil? lst) @@ -11,11 +15,13 @@ (rev (rest lst) (cons (first lst) acc)))) (rev lst nil)) +;</pre> ; pg. 32 -(comment - Clojure doesn't provide multiple value bindings in the same way that Lisp does. Instead, you can construct a vector - of values and then deconstruct them easily on the return within a let) + +; Clojure doesn't provide multiple value bindings in the same way that Lisp does. Instead, you can construct a vector of values and then deconstruct them easily on the return within a let) + +;<pre lang="lisp"> (defn mytrunc [num] [(int num) (- num (int num))]) @@ -23,3 +29,6 @@ (let [[int_part frac_part] (mytrunc 26.21875)] (str int_part " and " frac_part)) +;</pre> + +; -m reading/onlisp/chapter3.clj b6773efd1be1f1b4a9c230eb3d8f1f0d0a61258a Fogus devnull@earthvssoup.com http://github.com/fogus/polyglot/commit/57c47ea45e93b27d2302a66eedc163284d627892 57c47ea45e93b27d2302a66eedc163284d627892 2008-09-30T09:48:48-07:00 2008-09-30T09:48:48-07:00 Some minor modifications and a placeholder for chap 4 349ebc7fe3ba35f6177d66a5c6144b73977cfc70 Fogus devnull@earthvssoup.com