Contents

# Encode

## About

Encode makes it easy use get meaningful descriptions from encoded values.

    task.status = 'P'
    task.status.decode # => 'Pending'
    
It also simplifies using constants to define encoded values and descriptions.

    task.status = Task::Status::New
    task.status # => 'N'
    task.status.decode # => 'New'

## Observations

1. Magic numbers and characters make code more difficult to maintain because they don't have instrinsic meaning.
1. Magic strings, while meaningful, make code more difficult to maintain because minor variations can cause subtle problems.
1. Literal values scattered throughout a codebase increase refactoring time and effort.
1. Mapping between encoded values and descriptions shouldn't require a lot of effort.

## Using Encoder

### Setup
    class Task < ActiveRecord::Base
      include Encoder
  
      code :status do
        Status::New      = "N"
        Status::Pending  = "P"
        Status::Finished = "F"
        Status::OverDue  = "O"
      end
  
      code :priority do
        Priority::High =  1
        Priority::Low =   5
      end
  
    end

### Usage Examples
    t = Task.new # => #<Task id: nil, status: nil, priority: nil>

    # Using a constant to assign the value
    t.status = Task::Status::New # => "N"
    t.status # => "N"
    t.status.decode # => "New"

    # Using a decoded value to assign the value
    t.priority = 1 # => 1
    t.priority # => 1
    t.priority.decode # => "High"

    # Obtaining a list of the constant names defined for each attribute
    Task::Status.constants # => ["Pending", "New", "OverDue", "Finished"]
    Task::Priority.constants # => ["Low", "High"]
    Task::Priority.values # => [5, 1]
    Task::Priority.mapping # => { "Low" => 5, "High" => 1 }
    

## To Do

- Auto-mixin on init
- Choose a better name
- Use shoulda or rspec
- Obtain list of constant values (for use with validations)

Copyright (c) 2010 Jon Morton, released under the MIT license

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
encoder-0.0.2	README.markdown