retry_if.rb

module Enumerable
  def retry_if(*klasses)
    e = nil
    self.each { |arg|
      begin
        return yield(arg)
      rescue *klasses => e
        next
      end
    }
    raise(e)
  end
end

if $0 == __FILE__
  require "test/unit"

  class RetryIfTest < Test::Unit::TestCase
    def test_array__success
      results = []
      begin
        value = [1, 2].retry_if(RuntimeError) { |i|
          results << "i:#{i}"
          i
        }
      rescue => e
        results << "#{e.class.name}:#{e.message}"
      end

      assert_equal(["i:1"], results)
      assert_equal(1, value)
    end

    def test_array__fail_success
      results = []
      begin
        value = [1, 2].retry_if(RuntimeError) { |i|
          results << "i:#{i}"
          raise("1") if i == 1
          i
        }
      rescue => e
        results << "#{e.class.name}:#{e.message}"
      end

      assert_equal(["i:1", "i:2"], results)
      assert_equal(2, value)
    end

    def test_array__fail
      results = []
      begin
        value = [1, 2].retry_if(RuntimeError) { |i|
          results << "i:#{i}"
          raise("1") if i == 1
          raise("2") if i == 2
          i
        }
      rescue => e
        results << "#{e.class.name}:#{e.message}"
      end

      assert_equal(["i:1", "i:2", "RuntimeError:2"], results)
      assert_equal(nil, value)
    end

    def test_enum__fail_success
      results = []
      begin
        value = 2.times.retry_if(RuntimeError) { |i|
          results << "i:#{i}"
          raise("0") if i == 0
          i
        }
      rescue => e
        results << "#{e.class.name}:#{e.message}"
      end

      assert_equal(["i:0", "i:1"], results)
      assert_equal(1, value)
    end

    def test_multiple_exception_type
      results = []
      begin
        value = [1, 2, 3].retry_if(ArgumentError, TypeError) { |i|
          results << "i:#{i}"
          raise(ArgumentError, "1") if i == 1
          raise(TypeError, "2") if i == 2
          i
        }
      rescue => e
        results << "#{e.class.name}:#{e.message}"
      end

      assert_equal(["i:1", "i:2", "i:3"], results)
      assert_equal(3, value)
    end

    def test_uncaught_exception_type
      results = []
      begin
        value = [1, 2, 3].retry_if(ArgumentError, TypeError) { |i|
          results << "i:#{i}"
          raise("1") if i == 1
          i
        }
      rescue => e
        results << "#{e.class.name}:#{e.message}"
      end

      assert_equal(["i:1", "RuntimeError:1"], results)
      assert_equal(nil, value)
    end
  end
end