├── .gitignore ├── .rspec ├── .travis.yml ├── CODE_OF_CONDUCT.md ├── Gemfile ├── LICENSE.txt ├── README.md ├── Rakefile ├── bin ├── console └── setup ├── lib ├── method_pattern.rb └── method_pattern │ └── version.rb ├── method_pattern.gemspec └── spec ├── method_pattern_spec.rb └── spec_helper.rb /.gitignore: -------------------------------------------------------------------------------- 1 | /.bundle/ 2 | /.yardoc 3 | /_yardoc/ 4 | /coverage/ 5 | /doc/ 6 | /pkg/ 7 | /spec/reports/ 8 | /tmp/ 9 | 10 | # rspec failure tracking 11 | .rspec_status 12 | Gemfile.lock 13 | -------------------------------------------------------------------------------- /.rspec: -------------------------------------------------------------------------------- 1 | --format documentation 2 | --color 3 | --require spec_helper 4 | -------------------------------------------------------------------------------- /.travis.yml: -------------------------------------------------------------------------------- 1 | sudo: false 2 | language: ruby 3 | rvm: 4 | - 2.3.5 5 | before_install: gem install bundler -v 1.16.1 6 | -------------------------------------------------------------------------------- /CODE_OF_CONDUCT.md: -------------------------------------------------------------------------------- 1 | # Contributor Covenant Code of Conduct 2 | 3 | ## Our Pledge 4 | 5 | In the interest of fostering an open and welcoming environment, we as 6 | contributors and maintainers pledge to making participation in our project and 7 | our community a harassment-free experience for everyone, regardless of age, body 8 | size, disability, ethnicity, gender identity and expression, level of experience, 9 | nationality, personal appearance, race, religion, or sexual identity and 10 | orientation. 11 | 12 | ## Our Standards 13 | 14 | Examples of behavior that contributes to creating a positive environment 15 | include: 16 | 17 | * Using welcoming and inclusive language 18 | * Being respectful of differing viewpoints and experiences 19 | * Gracefully accepting constructive criticism 20 | * Focusing on what is best for the community 21 | * Showing empathy towards other community members 22 | 23 | Examples of unacceptable behavior by participants include: 24 | 25 | * The use of sexualized language or imagery and unwelcome sexual attention or 26 | advances 27 | * Trolling, insulting/derogatory comments, and personal or political attacks 28 | * Public or private harassment 29 | * Publishing others' private information, such as a physical or electronic 30 | address, without explicit permission 31 | * Other conduct which could reasonably be considered inappropriate in a 32 | professional setting 33 | 34 | ## Our Responsibilities 35 | 36 | Project maintainers are responsible for clarifying the standards of acceptable 37 | behavior and are expected to take appropriate and fair corrective action in 38 | response to any instances of unacceptable behavior. 39 | 40 | Project maintainers have the right and responsibility to remove, edit, or 41 | reject comments, commits, code, wiki edits, issues, and other contributions 42 | that are not aligned to this Code of Conduct, or to ban temporarily or 43 | permanently any contributor for other behaviors that they deem inappropriate, 44 | threatening, offensive, or harmful. 45 | 46 | ## Scope 47 | 48 | This Code of Conduct applies both within project spaces and in public spaces 49 | when an individual is representing the project or its community. Examples of 50 | representing a project or community include using an official project e-mail 51 | address, posting via an official social media account, or acting as an appointed 52 | representative at an online or offline event. Representation of a project may be 53 | further defined and clarified by project maintainers. 54 | 55 | ## Enforcement 56 | 57 | Instances of abusive, harassing, or otherwise unacceptable behavior may be 58 | reported by contacting the project team at jgaskins@gmail.com. All 59 | complaints will be reviewed and investigated and will result in a response that 60 | is deemed necessary and appropriate to the circumstances. The project team is 61 | obligated to maintain confidentiality with regard to the reporter of an incident. 62 | Further details of specific enforcement policies may be posted separately. 63 | 64 | Project maintainers who do not follow or enforce the Code of Conduct in good 65 | faith may face temporary or permanent repercussions as determined by other 66 | members of the project's leadership. 67 | 68 | ## Attribution 69 | 70 | This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4, 71 | available at [http://contributor-covenant.org/version/1/4][version] 72 | 73 | [homepage]: http://contributor-covenant.org 74 | [version]: http://contributor-covenant.org/version/1/4/ 75 | -------------------------------------------------------------------------------- /Gemfile: -------------------------------------------------------------------------------- 1 | source "https://rubygems.org" 2 | 3 | git_source(:github) {|repo_name| "https://github.com/#{repo_name}" } 4 | 5 | # Specify your gem's dependencies in method_pattern.gemspec 6 | gemspec 7 | -------------------------------------------------------------------------------- /LICENSE.txt: -------------------------------------------------------------------------------- 1 | The MIT License (MIT) 2 | 3 | Copyright (c) 2018 Jamie Gaskins 4 | 5 | Permission is hereby granted, free of charge, to any person obtaining a copy 6 | of this software and associated documentation files (the "Software"), to deal 7 | in the Software without restriction, including without limitation the rights 8 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 9 | copies of the Software, and to permit persons to whom the Software is 10 | furnished to do so, subject to the following conditions: 11 | 12 | The above copyright notice and this permission notice shall be included in 13 | all copies or substantial portions of the Software. 14 | 15 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 18 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 21 | THE SOFTWARE. 22 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # MethodPattern 2 | 3 | Pattern matching for Ruby methods 4 | 5 | ## Installation 6 | 7 | Add this line to your application's Gemfile: 8 | 9 | ```ruby 10 | gem 'method_pattern' 11 | ``` 12 | 13 | And then execute: 14 | 15 | $ bundle 16 | 17 | Or install it yourself as: 18 | 19 | $ gem install method_pattern 20 | 21 | ## Usage 22 | 23 | Extend any class you want to be able to use pattern matching with the `MethodPattern` module: 24 | 25 | ```ruby 26 | class HandleResponse 27 | extend MethodPattern 28 | end 29 | ``` 30 | 31 | Then you can define your method with `defn`: 32 | 33 | ```ruby 34 | class HandleResponse 35 | extend MethodPattern 36 | 37 | defn :call do 38 | # ... 39 | end 40 | end 41 | ``` 42 | 43 | Inside of your `defn` block, you declare your argument patterns using `with`: 44 | 45 | ```ruby 46 | class Fibonnaci 47 | extend MethodPattern 48 | 49 | defn :call do 50 | with(0..1) { |n| n } 51 | with(Integer) { |n| call(n - 1) + call(n - 2) } 52 | end 53 | end 54 | ``` 55 | 56 | This example will handle 0 and 1 as special cases and all other integers are funneled into the second implementation. Patterns declared higher take precedence. 57 | 58 | Notice that we could pass in a class or even a range for our pattern. There are several things we can use: 59 | 60 | - Strings: `with('hello') { |str| ... }` matches an exact string 61 | - Numbers: `with(15) { |num| ... }` matches an exact number 62 | - Symbol: `with(:foo) { |sym| ... }` matches a particular symbol 63 | - Class: `with(Integer) { |num| ... }` matches any instance of the given class 64 | - Regex: `with(/foo/) { |str| ... }` matches any string that matches the regex 65 | - Range: `with(0...10) { |num| ... }` matches any value covered by the range 66 | - Proc/lambda: `with(-> n { n > 3 }) { |n| ... }` matches if the proc returns a truthy value 67 | 68 | Note that the method arguments are passed to the block. This lets the block become the method body. 69 | 70 | ### It's not just for single arguments 71 | 72 | You can pass multiple patterns to `with` and it will match them in order: 73 | 74 | ```ruby 75 | defn :baz do 76 | with('foo', /bar/) { |a, b| a + b } 77 | end 78 | ``` 79 | 80 | ### Keyword arguments 81 | 82 | Keyword arguments work, too: 83 | 84 | ```ruby 85 | class HandleResponse 86 | extend MethodPattern 87 | 88 | defn :call do 89 | with status: 200...300, headers: { 'Content-Type': /json/ } do |body:, **| 90 | JSON.parse(body, symbolize_names: true) 91 | end 92 | 93 | # All 4xx and 5xx responses are errors 94 | with(status: 400..599) { |body:, **| ErrorResponse.call body } 95 | end 96 | end 97 | ``` 98 | 99 | ### Caveats 100 | 101 | Unfortunately, because `with` accepts its own block, you cannot match on whether a block was passed to the method. 102 | 103 | ## Development 104 | 105 | After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment. 106 | 107 | To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org). 108 | 109 | ## Contributing 110 | 111 | Bug reports and pull requests are welcome on GitHub at https://github.com/jgaskins/method_pattern. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct. 112 | 113 | ## License 114 | 115 | The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT). 116 | 117 | ## Code of Conduct 118 | 119 | Everyone interacting in the MethodPattern project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the [code of conduct](https://github.com/jgaskins/method_pattern/blob/master/CODE_OF_CONDUCT.md). 120 | -------------------------------------------------------------------------------- /Rakefile: -------------------------------------------------------------------------------- 1 | require "bundler/gem_tasks" 2 | require "rspec/core/rake_task" 3 | 4 | RSpec::Core::RakeTask.new(:spec) 5 | 6 | task :default => :spec 7 | -------------------------------------------------------------------------------- /bin/console: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env ruby 2 | 3 | require "bundler/setup" 4 | require "method_pattern" 5 | 6 | # You can add fixtures and/or initialization code here to make experimenting 7 | # with your gem easier. You can also use a different console, if you like. 8 | 9 | # (If you use this, don't forget to add pry to your Gemfile!) 10 | # require "pry" 11 | # Pry.start 12 | 13 | require "irb" 14 | IRB.start(__FILE__) 15 | -------------------------------------------------------------------------------- /bin/setup: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env bash 2 | set -euo pipefail 3 | IFS=$'\n\t' 4 | set -vx 5 | 6 | bundle install 7 | 8 | # Do any other automated setup that you need to do here 9 | -------------------------------------------------------------------------------- /lib/method_pattern.rb: -------------------------------------------------------------------------------- 1 | require "method_pattern/version" 2 | 3 | module MethodPattern 4 | def defn name, &definition 5 | fn = PatternMatchedFunction.new(name) 6 | fn.instance_exec(&definition) 7 | 8 | define_method name do |*args, &block| 9 | instance_exec(*args, &fn.match(args)) 10 | rescue => e 11 | raise e, e.message, caller[2..-1] 12 | end 13 | end 14 | 15 | class PatternMatchedFunction 16 | def initialize name 17 | @name = name 18 | @patterns = [] 19 | @default = proc do |*args| 20 | raise ArgumentError, 21 | "method #{self.class.inspect}##{name} does not know how to handle arguments: #{args.map(&:inspect).join(', ')}" 22 | end 23 | end 24 | 25 | def with *patterns, &block 26 | @patterns << Pattern.new(patterns, block) 27 | end 28 | 29 | def match args 30 | @patterns.each do |pattern| 31 | if pattern.match? args 32 | return pattern.block 33 | end 34 | end 35 | 36 | @default 37 | end 38 | 39 | class Pattern 40 | attr_reader :accepted, :block 41 | 42 | def initialize accepted, block 43 | @accepted = accepted 44 | @block = block 45 | end 46 | 47 | def match? args 48 | @accepted.each_with_index do |pattern, index| 49 | return false unless match_arg?(pattern, args[index]) 50 | end 51 | 52 | true 53 | end 54 | 55 | def match_arg? pattern, arg 56 | case pattern 57 | when Hash 58 | return false unless arg.is_a? Hash 59 | 60 | pattern.each do |key, value| 61 | return false unless arg.key?(key) && match_arg?(value, arg[key]) 62 | end 63 | 64 | true 65 | else 66 | pattern === arg 67 | end 68 | end 69 | end 70 | end 71 | end 72 | -------------------------------------------------------------------------------- /lib/method_pattern/version.rb: -------------------------------------------------------------------------------- 1 | module MethodPattern 2 | VERSION = "0.1.2" 3 | end 4 | -------------------------------------------------------------------------------- /method_pattern.gemspec: -------------------------------------------------------------------------------- 1 | 2 | lib = File.expand_path("../lib", __FILE__) 3 | $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib) 4 | require "method_pattern/version" 5 | 6 | Gem::Specification.new do |spec| 7 | spec.name = "method_pattern" 8 | spec.version = MethodPattern::VERSION 9 | spec.authors = ["Jamie Gaskins"] 10 | spec.email = ["jgaskins@gmail.com"] 11 | 12 | spec.summary = %q{Pattern matching for methods} 13 | spec.homepage = "https://github.com/jgaskins/method_pattern" 14 | spec.license = "MIT" 15 | 16 | spec.files = `git ls-files -z`.split("\x0").reject do |f| 17 | f.match(%r{^(test|spec|features)/}) 18 | end 19 | spec.bindir = "exe" 20 | spec.executables = spec.files.grep(%r{^exe/}) { |f| File.basename(f) } 21 | spec.require_paths = ["lib"] 22 | 23 | spec.add_development_dependency "bundler", "~> 1.16" 24 | spec.add_development_dependency "rake", "~> 10.0" 25 | spec.add_development_dependency "rspec", "~> 3.0" 26 | end 27 | -------------------------------------------------------------------------------- /spec/method_pattern_spec.rb: -------------------------------------------------------------------------------- 1 | require 'method_pattern' 2 | require 'json' 3 | 4 | c = Class.new do 5 | extend MethodPattern 6 | 7 | def initialize 8 | @zomg = 'lol' 9 | end 10 | 11 | defn :foo do 12 | with(123) { @zomg } 13 | with(/lo+l/) { 'LMAO' } 14 | with('a', /b/) { |a, b| a + b } 15 | with(String) { |str| str.upcase } 16 | with status: 200...300, headers: { 'Content-Type': /json/ } do |body:, **| 17 | JSON.parse(body, symbolize_names: true) 18 | end 19 | with status: 404, headers: { 'Content-Type': /json/ } do 20 | 'Not found' 21 | end 22 | with(->x { x > 3 }) { |x| x * 3 } 23 | end 24 | 25 | defn :factorial do 26 | with(1) { 1 } 27 | with(Integer) { |n| n * factorial(n - 1) } 28 | end 29 | 30 | defn :fibonacci do 31 | with(0..1) { |n| n } 32 | with(-> n { n.positive? }) { |n| fibonacci(n - 1) + fibonacci(n - 2) } 33 | end 34 | end 35 | 36 | RSpec.describe MethodPattern do 37 | describe 'pattern matching' do 38 | let(:o) { c.new } 39 | 40 | it 'allows recursion' do 41 | expect(o.factorial(1)).to eq 1 42 | expect(o.factorial(2)).to eq 2 43 | expect(o.factorial(3)).to eq 6 44 | expect(o.factorial(4)).to eq 24 45 | expect(o.factorial(5)).to eq 120 46 | 47 | expect(o.fibonacci(0)).to eq 0 48 | expect(o.fibonacci(1)).to eq 1 49 | expect(o.fibonacci(2)).to eq 1 50 | expect(o.fibonacci(3)).to eq 2 51 | expect(o.fibonacci(4)).to eq 3 52 | expect { o.fibonacci -1 }.to raise_error ArgumentError 53 | end 54 | it 'matches procs' do 55 | expect(o.foo(4)).to eq 12 56 | end 57 | it 'matches numbers' do 58 | expect(o.foo(123)).to eq 'lol' 59 | end 60 | it 'matches a string value' do 61 | expect(o.foo('zomg')).to eq 'ZOMG' 62 | end 63 | it 'matches a string regex pattern' do 64 | expect(o.foo('looool')).to eq 'LMAO' 65 | end 66 | it 'matches multiple arguments' do 67 | expect(o.foo('a', 'b')).to eq 'ab' 68 | end 69 | it 'matches recursive patterns on hash keys/values' do 70 | expect(o.foo( 71 | status: 200, 72 | headers: { 73 | 'Content-Type': 'application/json', 74 | 'Content-Length': 1234, 75 | }, 76 | body: { foo: 'bar' }.to_json, 77 | )).to eq(foo: 'bar') 78 | expect(o.foo( 79 | status: 404, 80 | headers: { 81 | 'Content-Type': 'application/json', 82 | 'Content-Length': 1234, 83 | }, 84 | )).to eq 'Not found' 85 | end 86 | 87 | it 'raises an ArgumentError if no patterns match' do 88 | expect { o.foo(:bar, 'baz', 123, ['lol']) } 89 | .to raise_error(ArgumentError) 90 | end 91 | end 92 | end 93 | -------------------------------------------------------------------------------- /spec/spec_helper.rb: -------------------------------------------------------------------------------- 1 | require "bundler/setup" 2 | require "method_pattern" 3 | 4 | RSpec.configure do |config| 5 | # Enable flags like --only-failures and --next-failure 6 | config.example_status_persistence_file_path = ".rspec_status" 7 | 8 | # Disable RSpec exposing methods globally on `Module` and `main` 9 | config.disable_monkey_patching! 10 | 11 | config.expect_with :rspec do |c| 12 | c.syntax = :expect 13 | end 14 | end 15 | --------------------------------------------------------------------------------