jimweirich

;; SICP 1.4
;;
;; Exercise 1.4.  Observe that our model of evaluation allows for
;; combinations whose operators are compound expressions. Use this
;; observation to describe the behavior of the following procedure:

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

;; (a-plus-abs-b 2 3)

jimweirich

;; SICP 1.5

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

jimweirich

;; SICP 1.5

;; Exercise 1.5.  Ben Bitdiddle has invented a test to determine
;; whether the interpreter he is faced with is using applicative-order
;; evaluation or normal-order evaluation. He defines the following two
;; procedures:

;; (define (p) (p))
;;
;; (define (test x y)

jimweirich

;; SICP 1.7

;; Exercise 1.7.  The good-enough? test used in computing square roots
;; will not be very effective for finding the square roots of very
;; small numbers. Also, in real computers, arithmetic operations are
;; almost always performed with limited precision. This makes our test
;; inadequate for very large numbers. Explain these statements, with
;; examples showing how the test fails for small and large numbers. An
;; alternative strategy for implementing good-enough? is to watch how
;; guess changes from one iteration to the next and to stop when the

jimweirich

;; Exercise 1.8.  Newton's method for cube roots is based on the fact
;; that if y is an approximation to the cube root of x, then a better
;; approximation is given by the value
;;
;; Use this formula to implement a cube-root procedure analogous to
;; the square-root procedure. (In section 1.3.4 we will see how to
;; implement Newton's method in general as an abstraction of these
;; square-root and cube-root procedures.)

;; ANSWER ------------------------------------------------------------

jimweirich

class C
  CC = Object.new
  def self.new
    CC
  end
end

jimweirich

def f(should_fail=false)
  puts "BODY 1"
  fail if should_fail
  puts "BODY 2"
rescue StandardError => ex
  puts "RESCUE"
else
  puts "ELSE"
ensure
  puts "ENSURE"

jimweirich

#!/usr/bin/env ruby

require 'rubygems'
require 'ripper'
require 'sorcerer'

class EvalErr
  def initialize(str)
    @string = str
  end

jimweirich

class FL
  def initialize(array)
    @ary = array
  end
  def ==(array)
    to_ary == array
  end
  def to_ary
    @ary
  end

jimweirich

class FL
  def initialize(array)
    @ary = array
  end
  def ==(array)
    to_ary == array
  end
  def to_ary
    @ary
  end