Angular style dependency injector. uses block param names to resolve dependency

injector.rb

class ResolutionError < StandardError; end

module Injector
  extend self

  @dependencies = {}

  def register(dependency, resolution)
    @dependencies[dependency] = resolution
  end

  def resolve(dependency)
    @dependencies[dependency] or raise ResolutionError.new("Failed to resolve `#{dependency}`")
  end
  
  def invoke(&block)
    resolutions = block.parameters.map {|_, name| resolve(name) }

    block.call(*resolutions)
  end
end

class SomeService
end

Injector.register(:service, SomeService.new)
Injector.register(:magic, 922)

Injector.invoke do |magic, service|
  puts magic, service
end

Injector.invoke {|foo| puts foo } # raises error: Failed to resolve `foo`