From: matz@... (Yukihiro Matsumoto) Date: 2001-07-15T00:50:37+09:00 Subject: [ruby-talk:17847] Re: What is Array#- ? Hi, In message "[ruby-talk:17794] Re: What is Array#- ?" on 01/07/13, Dave Thomas writes: |Matz: | |Wouldn't it be clearer to define a new Set type, rather than new |operations? Yes. When Set is what you want, Set is the cleanest way. But, I just wanted Array subtraction, and set-like behavior is say side-effect of performance boost. Array#- etc. may slow down some programs (e.g. rubicon) significantly. That's why I needed performance hack. So you can persuade me that either * performance is not significant for this operation. * there's better algorithm that makes both performance and duplication possible. matz.