control-flow.rb

#control flows

#br inside block -> forward jump
#br inside loop -> backward jump


#if

  ret = nil
  catch(:a) do
    if condition
      ret = ...
      throw :a # br 0
    else
    end
  end

  # または、breakできるifを定義
  def _if(condition, &block)
    if condition
      yield block
    end
  end

  ret = nil
  _if condition do
    ret = ...
    break # br 0
  end

  # あるいは

  ret,level =
  _if condition do
    break 返り値,0 # br 0
  end
  # break ret1,level-1 if level != 0 # トップレベルでは書かない

  # ここで気づいたが、_ifだとelseがでてきたときに面倒そう
  # 面倒だし、普通にifを使えば良さそう。ifの中のbr 0はサポートしない

#block

  ret = nil
  catch(:a) do
    ret = ...
    next # br 0

    ret = ...
  end

  # または

  ret =
  while true
    break 返り値 # br 0
    break 返り値 # end
  end

#loop

  while true
    ret = ...
    next # br 0

    ret = ...
    break
  end

  # または

  ret =
  while true
    next # br 0
    break 返り値 # end
  end

#block loop (advanced)

  ret = nil
  while true
    ret = ...
    break # br 1

    ret = ...
    next # br 0
  end

  # または

  ret =
  while true
    break 返り値 # br 1

    next # br 0

    break 返り値 # end
  end

  # または

  ret0 =
  while true

    ret1,level =
    while true
      next # br 0
      break 返り値,1 # br 1
      break 返り値,0 # end
    end
    break ret1,level-1 if level != 0
  end

#block if

  ret0 = nil
  catch(:b) do

    ret1 = nil
    catch(:a) do
      if condition
        ret1 = ...
        throw :b # br 0

        ret1 = ...
        throw :b # br 1
      else
      end
      ret1 = ...
    end

    ret0 = ...
  end

  # または

  ret0,level =
  while true

    ret1,level =
    _if condition do
      break 返り値,0 # br 0
      break 返り値,1 # br 1
    end
    break ret1,level-1 if level != 0

    break 返り値,0 # end
  end
  # next ret1,level-1 if level != 0 # トップレベルでは書かない

  # または

  ret0,level =
  while true
    ret1,level =
    if condition do
      break ret0の返り値,1 # br 1 (br 0はサポートしない）
    end
    break ret1,level-1 if level != 0
  end


#loop if

  ret0 = nil
  while true
    ret0 = ...
    next # br 0

    ret1 = nil
    catch(:a) do
      if condition

        ret0 = ...
        next # br 1

        ret1 = ...
        throw :a # br 0
      else
      end
    end

    ret = ...
    break
  end

  # または

  ret0,level =
  while true
    next # br 0

    ret1,level =
    _if condition do
      break 返り値,0 # br 0
      break 返り値,1 # br 1
    end
    next ret1,level-1 if level != 0

    break 返り値,0 # end
  end
  # break ret1,level-1 if level != 0 # トップレベルでは書かない

controls.rb

class Controls
  def _if(condition, then_proc, &else_block)
    if condition
      then_proc.call
    elsif else_block
      yield else_block
    else
      -1
    end
  end

  def _loop(&block)
    while true
      depth = yield block
      next if depth == 0
      return depth
    end
  end

  def _block(&block)
    yield block
  end


  def test1
    a = 1
    depth = _block{
      depth = _loop{
        depth = _if(a == 0, ->{
          a = 2
          next 1 # continue
          -1 # end
        }){ # else
          a = 3
          -1 # end
        }
        next depth - 1 if depth > 0
        -1 # end
      }
      next depth - 1 if depth > 0
      -1 # end
    }
    # assert(depth = 0)
    #p a
    a
  end

  def sum(p0)
    #v0 = 0
    #l0 = v0
    sum = 0
    #v1 = 1
    #l1 = v1
    i = 1
    depth = _block{
      depth = _loop{
        #v2 = l1
        #v3 = p0
        #v4 = v2 > v3
        #if v4
        if i > p0
          #break 1 # br_if
          next 1
        end
        #v5 = l0
        #v6 = l1
        #v7 = v5 + v6
        #l0 = v7
        sum = sum + i
        #v8 = l1
        #v9 = 1
        #v10 = v8 + v9
        #l1 = v10
        i = i + 1
        p 'hoge'
        #break 0 # continue
        next 0
        -1
      }
      p 'fuga'
      next depth - 1 if depth > 0
      -1
    }
    #v11 = l0
    #v11
    sum
  end

  def fact(p0)
    v0 = p0
    v1 = 0
    v2 = v0 == v1
    v3 = nil
    depth = _if(v2, ->{
      v4 = 1
      v3 = v4
      -1
    }){ # else
      v5 = p0
      v6 = p0
      v7 = 1
      v8 = v6 - v7
      v9 = fact(v8)
      v10 = v5 * v9
      -1
    }
    v10
  end

  def test02()
    v0 = nil
    depth = _block{
      v1 = 1
      v2 = 0
      v3 = v2 == 0
      if v3
        v0 = v1
        next 0
      end
      v0 = v0
      -1
    }
  end
end

c = Controls.new
#1_000.times do
  #c.test1
#end
#p c.sum(10)
p c.fact(10)