rufus-decision
CSV based Ruby decision tables.
WARNING: this library is not maintained anymore. Sorry.
getting it
gem install rufus-decision
or add gem 'rufus-decision' to your Gemfile.
tools based on rufus-decision
- https://github.com/lastobelus/rudelo - Set Logic matcher
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") # => espadasMore 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(
'https://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')
# => falseIn this example, the CSV table is the direction CSV representation of the Google spreadsheet at : https://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.
redirections
(Courtesy of lastobelus)
To help with redirections, one can modify the above example into:
require 'rubygems'
require 'rufus/decision'
require 'open_uri_redirections'
# https://github.com/jaimeiniesta/open_uri_redirections
TABLE = Rufus::DecisionTable.new(
'http://spreadsheets.google.com/pub?key=pCkopoeZwCNsMWOVeDjR1TQ&output=csv',
:open_uri => { :allow_redirections => :safe })web demo
There is a small demo of an input table + a decision table. You can run it by doing :
# (ouch, kind of old style...)
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://localhost:4567/
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
https://github.com/jmettraux/rufus-decision/issues
source
https://github.com/jmettraux/rufus-decision
git clone git://github.com/jmettraux/rufus-decision.git
author
John Mettraux, jmettraux@gmail.com http://jmettraux.wordpress.com
license
MIT