practicingruby / rbp-book Goto Github PK

when visiting the site without the "www." part, it shows an "under construction page". This is confusing, it would be better to have the same content as "www.rubybestpractices.com"

(Reported by DrErnie on RBP blog)

There appears to be a typo in the last paragraph:

"the myriad collection languages that people are comfortable with."

"collection OF languages", perhaps?

http://files.droplr.com/files/1650231/oAabx.Chapter2.pdf

in is an operator, therefore not a valid identifier

On page 137 of Chapter 5 should the self#authenticate method be changed from this:

def self.authenticate(username, password) 
  user = new(username, password)
  user.authenticate(password)
rescue Net::LDAP::LdapError => e 
  ActiveRecord::Base.logger.debug "!!! LDAP Error: #{e.message} !!!" 
  false
end

To this since the initialize method only takes one parameter?

def self.authenticate(username, password) 
  user = new(username) # <= Remove the password parameter
  user.authenticate(password)
rescue Net::LDAP::LdapError => e 
  ActiveRecord::Base.logger.debug "!!! LDAP Error: #{e.message} !!!" 
  false
end

I'm not sure how those "pseudo-keyword arguments" work in the RBP code (ex "Ruby’s Secret Power: Flexible Argument Processing" pg 5):

# Pseudo-keyword arguments
def story(options)
  "#{options[:person]} went to town, riding on a #{options[:animal]}"
end

The example in the book is this:

story(animal: "Tiger", person: "Yankee Doodle")
# => "Yankee Doodle went to town, riding on a Tiger"

But if I enter that code into IRB:

irb(main):012:0> story(animal: "Tiger", person: "Yankee Doodle")
SyntaxError: compile error
(irb):12: syntax error, unexpected ':', expecting ')'
story(animal: "Tiger", person: "Yankee Doodle")
            ^
(irb):12: syntax error, unexpected ',', expecting $end
story(animal: "Tiger", person: "Yankee Doodle")
                     ^
    from (irb):12
    from :0

The example works if I use a hash (as I had expected):

irb(main):013:0> story(:animal => "Tiger", :person => "Yankee Doodle")
=> "Yankee Doodle went to town, riding on a Tiger"

So I'm wondering: how did the book's JSON/Python-esque code work? Is it running on Ruby 1.9 (1.8.7 here), or is there some hack I'm missing?

Method calls are parenthesized irregularly. For example, on page 21: In the ["y", "Y", "YeS", "YES", "yes"].each do |y| block, the calls to expect_output and assert are not parenthesized while provide_input is.

Chapter 4 / Regular Expressions / Don't Work Too Hard introduces the section with the following code:

["James Gray", "James gray", "james gray", "james Gray"].all? { |e| ?> e.match(/James|james Gray|gray/) }

The regex in this example (/James|james Gray|gray/) will match any string containing "James", or "james Gray", or "gray", which is probably not what you intended. That is,

>> "gray".match(/James|james Gray|gray/) && true
=> true
>> "Gray".match(/James|james Gray|gray/) && true
=> nil

Suggest either /(James|james) (Gray|gray)/ or /(?:James|james) (?:Gray|gray), or note that finding the bug is an exercise for the reader.

PDF link in README is invalid. NO such GitHub site.
http://sandal.github.com/rbp-book/pdfs/rbp_1-0.pdf

on pages 36 and 37 of rbp_1-0.pdf, the tests say:

must "return false when parsing #{y}" do

where they should say

must "return true when parsing #{y}" do

that is, "true" instead of "false"

Hi,

Was reading your book and fascinated by the Fibonacci example with Memoization. Tried it out and it doesn't work.

Attached is the code used and the error code

def fib(n) 
  @series[n] ||= fib(n-1) + fib(n-2)
end

p fib(50)

NoMethodError: undefined method `[]' for nil:NilClass

method fib in test2.rb at line 2
at top level in test2.rb at line 5

page 46, the TCPServer doesn't work as expected. To handle multiple lines of input, it needs to loop on the session.gets, and it would be good form to close the session afterwards.

Just for fun, I also added the ability to close the connection and shut down the server from the client:

require 'socket'
class Server 
  def initialize(port=3333) 
    @server   = TCPServer.new('127.0.0.1',port) 
    @handlers = {} 
  end 
  def handle(pattern, &block) 
    @handlers[pattern] = block 
  end 
  def run 
    @shutdown = false
    while !@shutdown and session = @server.accept 
    @running = true
     while @running and msg = session.gets 
        match = nil 
        @handlers.each do |pattern,block|
          if match = msg.match(pattern)
            instance_eval &block
            break session.puts(block.call(match))
          end 
        end 
        unless match 
          session.puts "Server received unknown message: #{msg}" 
        end 
      end
    session.close
    end 
  end 
end 


server = Server.new 
server.handle(/hello/i) { "Hello from server at #{Time.now}" } 
server.handle(/goodbye/i) { @running = false ; "Goodbye from server at #{Time.now}" } 
server.handle(/name is (\w+)/) { |m| "Nice to meet you #{m[1]}!" } 
server.handle(/shutdown/) {@shutdown = true ; "Shutting down now, Goodbye"}
server.run 

http://sandal.github.com/rbp-book/pdfs/rbp_1-0.pdf