Module: LambdaDriver::Context

Defined in:
lib/lambda_driver/context.rb

Constant Summary collapse

Identify = 
lambda{|f, x| f.call(x) }
Maybe = 
lambda{|f, x|
  mzero_method = x.respond_to?(:mzero?) ? :mzero? : :nil?
  x.send(mzero_method) ? x : f.call(x)
}
List = 
lambda{|f, x| x.map(&f) }
Reader = 
lambda{|f, (r, x)|
  # set reader env to thread local
  Thread.current[:lambda_driver_reader_ctx_ask] = r
  # define ask method to access context of reader
  f.binding.eval(<<-CODE)
    def ask
      Thread.current[:lambda_driver_reader_ctx_ask]
    end
  CODE

  begin
    [r, f.call(x)]
  ensure
    # tear down reader context
    Thread.current[:lambda_driver_reader_ctx_ask] = nil
    f.binding.eval("undef ask")
  end
}
Writer = 
lambda{|f, (x, w)|
  pool = w || []

  # set writer pool to thread local
  Thread.current[:lambda_driver_writer_ctx_pool] = pool
  # define tell method to write log to context
  f.binding.eval(<<-CODE)
    def tell(s)
      pool = Thread.current[:lambda_driver_writer_ctx_pool]
      pool <<  s
    end
  CODE

  begin
    [f.call(x), pool]
  ensure
    # tear down reader context
    Thread.current[:lambda_driver_writer_ctx_pool] = nil
    f.binding.eval("undef tell")
  end
}

Class Method Summary collapse

Class Method Details

.[](name) ⇒ Object 



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# File 'lib/lambda_driver/context.rb', line 54

def self.[](name)
  name = name.to_s.capitalize
  const_defined?(name) && const_get(name)
end