rufus-decision

= rufus-decision

== getting it

gem install rufus-decision

== blog posts

http://jmettraux.wordpress.com/2009/04/25/rufus-decision-11-ruby-decision-tables/

http://jmettraux.wordpress.com/2010/02/17/ruote-and-decision-tables/

== usage

More info at http://rufus.rubyforge.org/rufus-decision/Rufus/Decision/Table.html but here is a recap.

An example where a few rules determine which salesperson should interact with a customer with given characteristics.

require 'rubygems' require 'rufus/decision'

TABLE = Rufus::Decision::Table.new(%{ in:age,in:trait,out:salesperson

18..35,,adeslky
25..35,,bronco
36..50,,espadas
51..78,,thorsten
44..120,,ojiisan

25..35,rich,kerfelden
,cheerful,swanson
,maniac,korolev

})

Given a customer (a Hash instance directly, for

convenience), returns the name of the first

corresponding salesman.

def determine_salesperson (customer)

TABLE.transform(customer)["salesperson"]

end

puts determine_salesperson( "age" => 72) # => thorsten

puts determine_salesperson( "age" => 25, "trait" => "rich") # => adeslky

puts determine_salesperson( "age" => 23, "trait" => "cheerful") # => adeslky

puts determine_salesperson( "age" => 25, "trait" => "maniac") # => adeslky

puts determine_salesperson( "age" => 44, "trait" => "maniac") # => espadas

More at Rufus::Decision::Table

Note that you can use a CSV table served over HTTP like in :

require 'rubygems' require 'rufus/decision'

TABLE = Rufus::DecisionTable.new( 'http://spreadsheets.google.com/pub?key=pCkopoeZwCNsMWOVeDjR1TQ&output=csv')

the CSV is :

in:weather,in:month,out:take_umbrella?

raining,,yes

sunny,,no

cloudy,june,yes

cloudy,may,yes

cloudy,,no

def take_umbrella? (weather, month=nil) h = TABLE.transform('weather' => weather, 'month' => month) h['take_umbrella?'] == 'yes' end

puts take_umbrella?('cloudy', 'june') # => true

puts take_umbrella?('sunny', 'june') # => false

In this example, the CSV table is the direction CSV representation of the Google spreadsheet at : http://spreadsheets.google.com/pub?key=pCkopoeZwCNsMWOVeDjR1TQ

WARNING though : use at your own risk. CSV loaded from untrusted locations may contain harmful code. The rufus-decision gem has an abstract tree checker integrated, it will check all the CSVs that contain calls in Ruby and raise a security error when possibly harmful code is spotted. Bullet vs Armor. Be warned.

== web demo

There is a small demo of an input table + a decision table. You can run it by doing :

gem install sinatra git clone git://github.com/jmettraux/rufus-decision.git cd rufus-decision ruby demo/start.rb

and then point your browser to http://localost:4567/

== uninstalling it

gem uninstall rufus-decision

== dependencies

The gem 'rufus-dollar' (http://rufus.rubyforge.org/rufus-dollar) and the 'rufus-treechecker' gem (http://rufus.rubyforge.org/rufus-treechecker).

== mailing list

On the rufus-ruby list :

http://groups.google.com/group/rufus-ruby

== irc

irc.freenode.net #ruote

== issue tracker

http://github.com/jmettraux/rufus-decision/issues

== source

http://github.com/jmettraux/rufus-decision

git clone git://github.com/jmettraux/rufus-decision.git

== author

John Mettraux, [e-mail] http://jmettraux.wordpress.com

== the rest of Rufus

http://rufus.rubyforge.org

== license

MIT