pzol

Monadic vs Imperative

Here is a comparison of two pieces of code that do basically the same thing.

So what we have here is a chain of functions depending on each other, each consecutive takes the result of the previous one for further processing. If either of them fails, the rest shall not be executed.

1. validate parameters received from the outside world in a Hash
2. convert one of the parameters into an object
3. do a search in the database

pzol

Running Puma on Nginx

I use the latest Puma v1.4.0 from rubygems.

Make sure you have nginx installed with these options:

>/opt/nginx/sbin/nginx -V
nginx version: nginx/1.0.15

built by gcc 4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3)

pzol

class MonadicHotelBookingPresenter
  def initialize(booking)
    @booking = Maybe(booking)
  end

  def hotel_name
    hotel_details['name'].fetch.to_s
  end

  def hotel_category

pzol

def Maybe(obj)
  return Maybe.new(Nothing.new) if obj.nil?
  return Maybe.new(obj)
end

class Nothing
  def method_missing(*args, &block)
    self
  end

pzol

feature 'Drinking Beer' do

  scenario 'Drink a favorite beer' do
    user = TestUser.new.extend(BeerDrinker)
    user.pickup_favorite_beer "Belfast"
    user.drinks_chosen_beer!
  end

  scenario "Getting wasted" do
    user = TestUser.new.extend(BeerDrinker)

pzol

sudo bash -l -c 'rvm implode && rm -rf /etc/rvmrc /usr/local/bin/rvm* /usr/local/rvm'
rm ~/.rvmrc
bash -s stable < <(curl -s https://raw.github.com/wayneeseguin/rvm/master/binscripts/rvm-installer )

rvm reload

# check if it is loaded correctly, this should return rvm is a function
type rvm | head -n 1

pzol

This was a test with Poltergeist I did the other day

#!ruby
def polter
   noop

end

pzol

# encoding: UTF-8

# parsing with EOF throws illegal characters!?
json = <<EOF
{
  "date_a": "2011-07-22T09:54:44Z",
  "city": "wroc\u0142aw",               # after this the next date is not parsed anymore!
  "date_b": "2011-07-22T09:54:44Z" 
}
EOF

pzol

# this does not run as a complete script :(
pkg_add -r bash curl sudo
pkg_add -r git vim               # can you live without it?
pkg_add -r libxml2 libxslt       # for nokogiri later
pw usermod pzol -G wheel

bash                             # start bash and run the rest inside it
curl -# -L http://bit.ly/rvm-install-system-wide > rvm-install-system-wide
bash -l < rvm-install-system-wide

pzol

#! /bin/sh

TINYPMVERSION=2.2.3

# from /etc/init.d/tomcat6
NAME=tomcat6
# Directory where the Tomcat 6 binary distribution resides
CATALINA_HOME=/usr/share/$NAME
# Directory for per-instance configuration files and webapps
CATALINA_BASE=/var/lib/$NAME