List comprehension in ruby

list_comprehension.rb

# Inspired by https://blog.engineyard.com/2014/ruby-list-comprehension

module Kernel
  def c(comprehension, &block)
    scope = block.send(:binding)
    if comprehension =~ /^\s*(\S.*)\s+for\s+(\S+)\s+in\s+(.*)$/
      amount, for_variable, in_range = $1,$2,$3
      scope.send(:eval, in_range).map do |value|
        scope.send(:eval, "#{for_variable} = #{value}")
        scope.send(:eval, "#{for_variable} = #{amount}")
        block.call( scope.send(:eval, "#{for_variable}" ) )
      end
    else
      'no comprende!'
    end
  end
end

class TestHarness
  def test
    wacky = 2
    in_my_scope = 7
    comprehension = 'n + wacky for n in [1, 2, 3, 4, 5]'

    result = c(comprehension) do |n|
      n * in_my_scope
    end
    expected = [21, 28, 35, 42, 49]
    puts "GIVEN:    
    wacky = 2
    in_my_scope = 7
    comprehension = 'n + wacky for n in [1, 2, 3, 4, 5]'
    ..."
    puts "Expected: #{expected.inspect}."
    puts "actual:   #{result.inspect}."
    puts (result == expected) ? "SUCCESS" : "** FAIL **"
    return result == expected
  end
end

puts "--- TESTING ---"
result = TestHarness.new.test
puts "--- end test --"
puts "TODO: get this to work: '[[print(str(x) for x in y] for 2 * y in xrange(1, 100)]'"

result