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language: ruby | ||
rvm: | ||
- 1.8.7 | ||
- 1.9.2 | ||
- 1.9.3 | ||
- jruby-18mode # JRuby in 1.8 mode | ||
- jruby-19mode # JRuby in 1.9 mode | ||
- rbx-18mode | ||
- rbx-19mode |
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# Maybelline | ||
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An implementation of the maybe monad. | ||
[![Build Status](http://travis-ci.org/blatyo/maybelline.png)](http://travis-ci.org/blatyo/maybelline) | ||
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An implementation of the [maybe monad](http://en.wikipedia.org/wiki/Monad_(functional_programming)#The_Maybe_monad). | ||
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## Setup | ||
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**Gemfile** | ||
``` ruby | ||
gem 'maybelline' | ||
``` | ||
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**Manual** | ||
``` ruby | ||
require 'maybelline' | ||
``` | ||
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## Usage | ||
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Say you have some objects like the ones below: | ||
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``` ruby | ||
class B | ||
def b | ||
nil | ||
end | ||
end | ||
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# if any method in the chain of calls returns nil, the | ||
# block will return nil | ||
Maybe(B){|b| b.new.b.this_method_wont_get_called} #=> nil | ||
B.maybe{|b| b.new.b.this_method_wont_get_called} #=> nil | ||
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# if it is successful, it will return the value | ||
1.maybe{|n| n.to_s(16).to_i.to_s(8)} #=> 1 | ||
``` | ||
require 'ostruct' | ||
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data = { | ||
"neat" => { | ||
"super" => "cool", | ||
"lame" => nil | ||
} | ||
} | ||
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object = OpenStruct.new(data) | ||
object.neat = OpenStruct.new(object.neat) | ||
``` | ||
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If any method in the chain of calls returns nil, the block will return nil. | ||
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``` ruby | ||
Maybe(data){|d| d["this_key_doesnt_exist"]["this_key_wont_get_called"]} #=> nil | ||
data.maybe{|d| d["this_key_doesnt_exist"]["this_key_wont_get_called"]} #=> nil | ||
object.maybe{|o| o.neat.lame.this_method_never_gets_called} #=> nil | ||
``` | ||
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If it is successful, it will return the value. | ||
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``` ruby | ||
data.maybe{|d| d["neat"]["super"]} #=> "cool" | ||
object.maybe{|o| o.neat.super} #=> "cool" | ||
``` | ||
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## Note on Reporting Issues | ||
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* Try to make a failing test case | ||
* Tell me which version of ruby you're using | ||
* Tell me which OS you are using | ||
* Provide me with any extra files if necessary | ||
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## Note on Patches/Pull Requests | ||
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* Fork the project. | ||
* Make your feature addition or bug fix. | ||
* Add tests for it. This is important so I don't break it in a future version unintentionally. | ||
* Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull) | ||
* Send me a pull request. Bonus points for topic branches. |
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require "bundler/gem_tasks" | ||
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require 'rspec/core/rake_task' | ||
RSpec::Core::RakeTask.new('spec') | ||
task :default => :spec | ||
task :test => :spec |