What Ruby’s ||= (Double Pipe / Or Equals) Really Does

Ruby Weekly is a weekly newsletter covering the latest Ruby and Rails news. In Rubyists Already Use Monadic Patterns, Dave Fayram made a passing reference to using ||= to set a variable's value if its value were 'Nothing' (false or nil in Ruby). The resulting Reddit quickly picked up on his definition (which was fixed later) and argued about ||='s true meaning which isn't as obvious as many Rubyis

[yujiorama]

古い記事だけど ||= は += とかの仲間じゃないし a = a || b でもないけど、a || a = b みたいに振る舞うという説明

[a666666]

これ Perl だとどうなるんだろう

[o_show]

a ||= b は a = a || b ではなく、 a || a = b

[kitokitoki]

||= 最後の例だけ？となった