ryanbriones

A list of things from Michael Feather's "The Self-Educating Craftsman" talk from Software Craftsmanship North America (courtesy of Jim Weirich). I'm still hoping Michael will put up his slides though...

Cheers!

* big-O notation
* covariance / contravariance
* types
* objects are closures
* State machines
* regular expressions & automata

ryanbriones

# usage: gh-archive ryanbriones/git-pair
function gh-archive() {
    name=${1%/*};
    project=${1##*/};
    mkdir "$name-$project";
    wget "http://github.com/$name/$project/tarball/master" -O- | tar zxvC "$name-$project" --strip 1;
}

ryanbriones

# how do I test this elegantly?

class Request < ActiveRecord::Base
  named_scope :active, :conditions => {:status => 'active'}
  named_scope :incomplete, :conditions => {:completed_at => nil}
  named_scope :deliquent, lambda { {:conditions => 10.days.ago} }
  
  def self.do_stuff_with_incomplete_requests
    incomplete_requests = Request.active.incomplete.deliquent(:include => {:user})
    incomplete_requests.each do |request|

ryanbriones

SICP 1.1
Fork me. Solve me.
====

;; I wasn't completely clear on the point of this exercise
;; so I tried doing them in my head before running them in the repl

10 ;; => 10
(+ 5 3 4) ;; => 12
(- 9 1) ;; => 8

ryanbriones

SICP 1.2
Fork me. Solve me.
====

(/ (+ 5 4 (- 2 (- 3 (+ 6 (/ 4 5)))))
   (* 3 (- 6 2) (- 2 7)))

;; => -37/150

ryanbriones

SICP 1.3
Fork me. Solve me.
====

(define (square x) (* x x))

(define (sum-of-squares a b) (+ (square a) (square b)))

(define (sum-two-largest-squares a b c)
  (cond ((and (< a b) (< a c))

ryanbriones

;; SICP 1.4
;; Fork me. Solve me.
;; ====

(define (a-plus-abs-b a b)
  ((if (> b 0) + -) a b))

(a-plus-abs-b 1 2)
;; ((if (> 2 0) + -) 1 2)
;; (+ 1 2)

ryanbriones

;; SICP 1.5

;; Given:
;;
;;     (define (p) (p))
;;
;;     (define (test x y)
;;       (if (= x 0)
;;           0
;;           y))

ryanbriones

;; SICP 1.6
;; Fork me. Solve me.

;; if is a special form that only evaluates the arguments after the predicate has been evaluated.
;; since new-if evaluates it's arguments immediately, the program is sent into an infinite loop
;; evaluating sqrt-iter with an improved guess

ryanbriones

;; SICP 1.8
;; Fork me. Solve me.

(define (cube x) (* x x x))

(define (improve y x)
  (/ (+ (/ x (* y y)) (* 2 y)) 3))

(define (good-enough? guess x)
  (< (abs (- (cube guess) x)) 0.001))