Typedeaf

Typedeaf is a gem to help add some type-checking to method declarations in Ruby

Usage

Writing your Typedeaf'd code

require 'typedeaf'

class Logger
  include Typedeaf

  # Log an error
  #
  # @param [String] messaage
  define :error, message: String do
    # Just delegate to the #log method nad pass
    # the level of error
    self.log(message, :error)
  end

  # Log a simple message to STDOUT
  #
  # @param [String] message The log message to log 
  # @param [Symbol] level The level at which to log the
  #     message, defaults to :info
  define :log, message: String, level: default(:info, Symbol) do
    puts "[#{level}] #{message}"
  end
end

Calling Typedeaf'd code

[1] pry(main)> require './logger'
=> true
[2] pry(main)> l = Logger.new
=> #<Logger:0x00000803c616b8>
[3] pry(main)> l.log 'test 1, 2, 3'
[info] test 1, 2, 3
=> nil
[4] pry(main)> l.log 'this is SUPER SERIOUS', :critical
[critical] this is SUPER SERIOUS
=> nil
[5] pry(main)> l.error(5) # wrong type!
Typedeaf::InvalidTypeException: Expected `message` to be a kind of String but was Fixnum
from /usr/home/tyler/source/github/ruby/typedeaf/lib/typedeaf.rb:58:in `type_validation!'
[6] pry(main)> l.log("This doesn't use the right type either", 1)
Typedeaf::InvalidTypeException: Expected `level` to be a kind of [Symbol] but was Fixnum
from /usr/home/tyler/source/github/ruby/typedeaf/lib/typedeaf.rb:58:in `type_validation!'
[7] pry(main)>

Passing blocks to Typedeaf code

require 'typedeaf'

class Logger
  include Typedeaf

  define :log, message: String, block: Proc do
    puts "Loggin: #{message}"
    block.call
  end
end

Logger.new.log('hello world') do
  puts 'called back!'
end

Caveats

Here's a list of caveats, or things that don't quite work, with Typedeaf:

Typedeaf methods cannot use return or break, since they're technically Ruby blocks and must follow the rules defined for block behaviors
yield will not properly work, if you want to pass blocks into your Typedeafed method, see the above usage example

Installation

Add this line to your application's Gemfile:

gem 'typedeaf'

And then execute:

$ bundle

Or install it yourself as:

$ gem install typedeaf

typedeaf