ngpestelos

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ngpestelos

# Video: http://rubyhoedown2008.confreaks.com/08-chris-wanstrath-keynote.html

Hi everyone, I'm Chris Wanstrath.

When Jeremy asked me to come talk, I said yes.  Hell yes.  Immediately.  But
then I took a few moments and thought, Wait, why?  Why me?  What am I supposed
to say that's interesting?  Something about Ruby, perhaps.  Maybe the
future of it.  The future of something, at least.  That sounds
keynote-y.

ngpestelos

Please refer to Erlang Programming, p. 199-200.

First, let's figure out how the splits function works. From the book, we have this definition:

1 splits([]) ->
2  [{[], []}];
3 splits([H | T] = Ys) ->
4  [ {[], Ys} | [ {[H | As], Bs} || {As, Bs} <- splits(T)]].

Here's what we know:

ngpestelos

See Erlang Programming, p. 199-200)

This is the second part of the program (see splits_trace).

1 perms([]) ->
2   [[]];
3 perms([X | Xs]) ->
4   [insert(X, As, Bs) || Ps <- perms(Xs), {As, Bs} <- splits(Ps)].

Before we proceed, we need to know two things:

ngpestelos

Here are the steps I took to get Rails working on an Ubuntu VirtualBox instance:

1. Software Versions
 
  * Ubuntu 9.04 (I'm using xubuntu-9.04 and I assume Rails wouldn't care)
  * Ruby 1.8.7
  * Rails 2.3
  * MySQL 5.x

ngpestelos

You're new to Rails and would like to create an application.

1. Generating the starting app

  $ rails demo
  $ cd demo
  $ ls -p
    README config/ lib/ script/ vendor/ Rakefile db/ log/ test/ app/ doc/ public/ tmp/

2. Creating a controller

ngpestelos

      === Epic Snow Leopard Upgrayyyyd Guide ===

Son, you’re now living in the land of 64-bit systems.

That means that some of your 32-bit shit is now broken.

Not all is lost.

== Fixing MySQL weirdness

ngpestelos

You want to switch databases from sqlite (default) to Rails.

1. Create the database

  $ mysql -u root create depot_development

2. Update config/database.yml

  development:
    adapter: mysql

ngpestelos

Stopped at 16:20

Important part @ 19:10

From a pattern, produce a skeleton using a rule.

> A pattern is something that matches, and a skeleton is something you substitute into in order to get a new expression (03:03)

> A pattern is matched against the expression and the result of the application of the rule is to produce a new expression (target) by instantiation of the skeleton

ngpestelos

-module(port_scanner).
-export([scan/3]).

scan(Addr, Start, End) ->
    Services = parse_services(),
    scan(Addr, Start, End, Services).

%% Internal functions
scan(Host, Start, End, Services) ->
    [Data || Data <-