class Cucumber::CucumberExpressions::CucumberExpression

def initialize(expression, parameter_type_registry)
  @source = expression
  @parameter_types = []
  expression = process_escapes(expression)
  expression = process_optional(expression)
  expression = process_alternation(expression)
  expression = process_parameters(expression, parameter_type_registry)
  expression = "^#{expression}$"
  @tree_regexp = TreeRegexp.new(expression)
end