From: Yusuke Endoh <redmine@...>
Date: 2009-08-18T23:54:03+09:00
Subject: [ruby-dev:39108] [Bug #1953] empty range in String#tr causes unexpected behavior

Bug #1953: empty range in String#tr causes unexpected behavior
http://redmine.ruby-lang.org/issues/show/1953

起票者: Yusuke Endoh
ステータス: Open, 優先度: Normal
Target version: 1.9.x
ruby -v: ruby 1.9.2dev (2009-08-18 trunk 24578) [i686-linux

Are these intentional?

  "ABC".tr("ABC", "pq-a")    #=> "pqq"
  "ABC".tr("ABC", "pq-ar")   #=> "prr"
  "ABC".tr("ABC", "pq-ars")  #=> "prs"
  "ABC".tr("ABC", "pq-arst") #=> "prs"

I expect that an exception is raised or that "p-a" equals to
"ponmlk...cba" (descending order).

For reference, empty range is rejected in Perl:

  $ perl -e '"A" =~ tr/A/q-a/;'
  Invalid range "q-a" in transliteration operator at -e line 1.

-- 
Yusuke ENDOH <mame@tsg.ne.jp>


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