* ольга крыжановская <[email protected]> [2012-03-09 20:19]:
> Clark, can you point me to the section of the standard which defines
> that ] must be the first characters in []? It feels not common sense,
> unsymmetrical and sounds like a nightmare for parsers. I believed that
> every character with a special meaning for extended regex must be
> escaped in cases where the user wants the character literally. Does
> the standard really define an exception here?


>From the XBD Issue 7 IEEE Std 1003.1-2008, 9.3.5 RE Bracket Expression
(online at 
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap09.html#tag_09_03_05):

    1. ... The right-bracket ( ']' ) shall lose its special meaning and
    represent itself in a bracket expression if it occurs first in the list
    (after an initial circumflex ( '^' ), if any). Otherwise, it shall
    terminate the bracket expression, unless it appears in a collating symbol
    (such as "[.].]" ) or is the ending right-bracket for a collating symbol,
    equivalence class, or character class.

-- 
Guido Berhoerster
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