gherkin-ruby's Introduction

gherkin-ruby

Gherkin-ruby is a pure Ruby implementation of a Gherkin parser.

Tested with MRI 1.9.2, 1.9.3, ruby-head and Rubinius head.

Why this one over the official, fast, Ragel-based Gherkin parser?

Less than 200 LOC.
No Java/.NET crap.
Fast enough for our purposes (using it for the Spinach project)

Install

$ gem install gherkin-ruby

Or in your Gemfile:

# Gemfile

gem 'gherkin-ruby'

Usage

You can easily implement your own visitors to traverse the Abstract Syntax Tree. The following example just prints the step names to standard output:

class MyVisitor
  def visit(ast)
    ast.accept(self)
  end

  def visit_Feature(feature)
    # Do something nasty with the feature
    # Set whatever state you want:
    #   @current_feature = feature
    # etc etc
    # And keep visiting its children:

    feature.each { |scenario| scenario.accept(self) }
  end

  def visit_Scenario(scenario)
    # Do something nasty with the scenario
    # Set whatever state you want:
    #   @current_scenario = scenario
    # etc etc
    # And keep visiting its children:

    scenario.each { |step| step.accept(self) }
  end

  def visit_Background(background)
    # Do something nasty with the background
    # And keep visiting its children:

    background.each { |step| step.accept(self) }
  end

  def visit_Tag(tag)
    # Do something nasty with the tag
  end

  def visit_Step(step)
    # Finally, print the step name.
    puts "STEP: #{step.name}"
  end
end

ast = Gherkin.parse(File.read('some.feature'))
visitor = MyVisitor.new
visitor.visit(ast)