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The Linux Console

linuxcommand.org

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Now what?

You have Linux installed and running. The GUI is working fine, but you are getting tired of changing your desktop themes. You keep seeing this "terminal" thing.

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Lesson 1

• Presentazione
• introduzione a bash, ruby, irb

Lesson 2

• Ruby basics (https://github.com/ict4g/ror-dw-2015/blob/gh-pages/guides/ruby-basics.md) no classes
• Simple function definition
• Everything is an expression
• Esercizi laboratorio/casa

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Spunti esercizi

• Dichiarazione di array
• accesso agli array
• free di ogni nodo usato (curare i mem leack?)
• deallocazione variabili locali (riparare lo scope)
• implementare il tipo di dato nativo float

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Authorization in ruby on rails

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Web framework

In a web framework, when we handle a request in our application, we always do the same things, every time:

• Authenticate the user
• Authorize the request

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"CanCan is an authorization library for Ruby on Rails which restricts what resources a given user is allowed to access. All permissions are defined in a single location (the Ability class) and not duplicated across controllers, views, and database queries."

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Installation

Add this to your Gemfile and run the bundle install command

gem 'cancancan', '~> 1.10'

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class Object
  def my_method(sym)
    MyMethod.new(self, sym)
  end
end

class MyMethod
  def initialize(obj, method)
    @obj, @method = obj, method
  end

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"A pundit is a person who offers to mass media their opinion or commentary on a particular subject area (typically political analysis, the social sciences, technology or sport) on which they are knowledgeable, or considered a scholar in said area" - Wikipedia

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"Pundit provides a set of helpers which guide you in leveraging regular Ruby classes and object oriented design patterns to build a simple, robust and scaleable authorization system" - Github

Installation

In your Gemfile:

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# http://codegolf.stackexchange.com/questions/64650/generate-toothpick-sequence

n = ARGV[0].to_i

$t = (n * 2).times.map { [' '] * n * 2}

def add_backslash_top (n,m,c)
  if $t[n] && $t[n][m] == " " && c!=0
    $t[n][m] = '\\'
    add_slash_left(n,m-1,c-1)

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damiano.stoffie@sci-b106pc035x:~$ lex --version
lex 2.5.35

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array = ["america", "europe", "asia", "africa", "france", "usa", "spain", "paris", "los angeles"]

definitions = {
  "continent" => ["america", "europe", "asia", "africa"],
  "country" => ["france", "usa", "spain"],
  "city" => ["paris", "los angeles"],
  "planet" => ["mars","earth"]
}

inverse_array = definitions.map {|k,v| v.map { |e| [e, k]}}.flatten(1)