If that were the correct interpretation, then '2'..'1' should be the same as '2'..'9' but: 

perl -de 0
  DB<1> p join " ", '2'..'1'

  DB<2> p join " ", '2'..'9'
2 3 4 5 6 7 8 9
  DB<3>

[download]
So it appears that perl 5.6.1 incorrectly doesn't realize that '0' comes before '1' when you write '1'..'0' but gets it correct for '1' through '8' since '9'..'8' and others give empty lists.

Note that 5.004_01 gets '1'..'0' correct but incorrectly thinks 'c'..'b' is the same 'c'..'z' (as does v5.6.0). So this is apparently a poorly-tested corner of the code.

...As well as being misleadingly documented. I'm confident that the original intent was that things like 'c'..'a' would return the empty list. So the code and the documentation both need to be patched to make this clear.

Update: Note that perl 4.036 realizes that '1'..'0' is the empty list but incorrectly thinks 'w'..'c' is the same as 'w'..'z'. So by no means a new bug. (:

        - tye (but my friends call me "Tye")

In reply to (tye)Re2: Range operator weirdness? by tye
in thread Range operator weirdness? by PrakashK

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