Study notes: Seven Languages in Seven Weeks

These are my annotations and exercises when reading the book Seven Languages in Seven Weeks by Bruce Tate.

Introduction

1.1 Method to the madness

For each programming language you're, answers for the following questions:

• What is the typing model?
• What is the programming model?
• How will you interact with it?
• What are the decision constructs and core data structures?
• What are the core features that make the language unique?

1.2 The languages

1.3 Buy this book

1.4 Don't buy this book

1.5 A Final Charge

2 Ruby

2.1 Quick History

• Created by Yukihiro Matsumoto in 1993
• Object oriented, duck (dynamically) typed, interpreted
• Productivity over performance, simplicity over safety

2.2 Day 1: Finding a Nanny

Using Ruby with the Console

The Programming Model

• Pure object oriented

Decisions

• Simplicity for conditionals
  • block form: if condition, statements, end
  • one-line form: statement if condition
• The same goes for while and until
• Logical operators
  • Short circuit: &&, ||, and, or
  • Non-short circuit: &, |

Duck typing

• Strongly typed: the type is always treated as expected
  • There are some exceptions
• Duck typed

Day 1 Self-Study

• Print the string “Hello, world.”

puts 'hello world'

• For the string “Hello, Ruby,” find the index of the word “Ruby.”

/Ruby/ =~ 'Hello, Ruby'

• Print your name ten times.

10.times {puts 'your name'}

• Print the string “This is sentence number 1,” where the number 1 changes from 1 to 10.

(1..10).each {|x| puts "This is sentence number #{x}"}

• Run a Ruby program from a file.

irb filepath.rb

• Bonus problem: If you’re feeling the need for a little more, write a program that picks a random number. Let a player guess the number, telling the player whether the guess is too low or too high.

def main
  num = rand(1..10)
  loop do
    guess = gets.to_i
    case
    when guess > num
      puts "too high"
    when guess < num
      puts "too low"
    when guess == num
      puts "you got it ;)"
      break
    end
  end
end