Module: RSpec::Core::Extensions::InstanceEvalWithArgs

Included in:
RSpec::Core::ExampleGroup, ModuleEvalWithArgs
Defined in:
lib/rspec/core/extensions/instance_eval_with_args.rb

Instance Method Summary collapse

Instance Method Details

#instance_eval_with_args(*args, &block) ⇒ Object

Used internally to support ‘instance_exec` in Ruby 1.8.6.

based on Bounded Spec InstanceExec (Mauricio Fernandez) eigenclass.org/hiki/bounded+space+instance_exec

  • uses singleton_class instead of global InstanceExecHelper module

  • this keeps it scoped to classes/modules that include this module

  • only necessary for ruby 1.8.6



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# File 'lib/rspec/core/extensions/instance_eval_with_args.rb', line 15

def instance_eval_with_args(*args, &block)
  return instance_exec(*args, &block) if respond_to?(:instance_exec)

  # If there are no args and the block doesn't expect any, there's no
  # need to fake instance_exec with our hack below.
  # Notes:
  #   * lambda { }.arity # => -1
  #   * lambda { || }.arity # => 0
  #   * lambda { |*a| }.arity # -1
  return instance_eval(&block) if block.arity < 1 && args.size.zero?

  singleton_class = (class << self; self; end)
  begin
    orig_critical, Thread.critical = Thread.critical, true
    n = 0
    n += 1 while respond_to?(method_name="__instance_exec#{n}")
    singleton_class.module_eval{ define_method(method_name, &block) }
  ensure
    Thread.critical = orig_critical
  end
  begin
    return send(method_name, *args)
  ensure
    singleton_class.module_eval{ remove_method(method_name) } rescue nil
  end
end