From: Gavin Sinclair <gsinclair@...>
Date: 2012-02-01T21:05:57+09:00
Subject: Re: Multiple assignment in conditional

On Wed, Feb 1, 2012 at 10:57 PM, Gavin Sinclair <gsinclair@gmail.com> wrote:

Sorry to reply to my own message, but I thought of something I should
have included.

Here is the forbidden version I would like to write.  Obviously I'm
combining assignment and conditional, which may not win plaudits as a
general rule.

>  def week_and_day(date)
>    if not self.include? date
>      return nil
>    elsif (week, day = @t1.week_and_day(date))
>      return [week, day]
>    elsif (week, day = @t2.week_and_day(date))
>      week += @t1.number_of_weeks
>      return [week, day]
>    end
>  end

But consider this alternative, where I separate the assignment and the
conditional.

  def week_and_day(date)
    if not self.include? date
      return nil
    else
      week, day = @t1.week_and_day(date)
      if week
        return [week, day]
      else
        week, day = @t2.week_and_day(date)
        week += @t1.number_of_weeks
        return [week, day]
      end
    end
  end

I consider this very clumsy.  By _not_ combining assignment with
conditional, I cannot use "elsif".  I must split the "else" and the
"if", and turn the second conditional into a child instead of a
sibling.

Definitely less intentional and unattractive code.

Gavin