Am 19.09.2010 22:33, schrieb Lee:
Thank you - I appreciate the follow-up.
Was the reply from the upstream maintainer answered on a mailing list?
(& if so, which one?) I'd like to understand the problem they're
solving.. I get the idea of "[[:lower:]]" working regardless of
collating order of the current char set, but how "[a-z]" gets
translated to something like "[aAbBcCdD...zZ]" boggles my mind. It
seems like they had to have gone out of their way to translate [a-z]
into a case-insensitive RE.
But regardless, it still seems broken to me. From the gawk man page:
The various command line options control how gawk interprets
characters in regular expressions.
--traditional
Traditional Unix awk regular expressions are matched. The GNU
operators are not special, interval expressions are not available, and
neither are the POSIX character classes ([[:alnum:]] and so on).
The way I read it, I can change the line in my .bashrc from
export AWK="/usr/bin/gawk.exe"
to
export AWK="/usr/bin/gawk.exe --traditional"
and not have to change any scripts that use $AWK. If "--traditional"
meant one no longer was able to do a case-sensitive RE ("[a-z]" gets
translated into "[aAbB...zZ]" and "[[:lower:]]" isn't interpreted as a
lower case character RE) I'd expect that to be high-lighted in the man
page. But like I said in my initial msg, --traditional doesn't fix
the problem:
$ cat test.awk
awk --traditional '
BEGIN {
s="Serial0"
gsub("[a-z]","",s)
printf("s= ::%s:: should = ::S0::\n", s)
exit
} '
$ export LANG=en_US.UTF-8
$ sh test.awk
s= ::0:: should = ::S0::
What you really want is this:
s/really want/have to do/
BEGIN {
s="Serial0"
gsub("[[:lower:]]","",s)
printf("s= ::%s:: should = ::S0::\n", s)
exit
}
The "[[:lower:]]" expression always catches all valid lowercase letters,
independent of the langauge, territory, and charset used.
At least for the short term, my work-around is not setting LANG.
Thanks again,
Lee
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Hello Lee,
you hit a well know problem with different character sets.
Normally it is not recognized, because the standard character set from
UNIX, LINUX And WINDOWS systems
have the characters "abcdefghijklmnopqrstuvwxyz" in a sequence. But this
is not the case for all character sets.
E.g. *EBCDIC* is one example for such a character set.
The different character set are a great problem for porting programs
from one system to another.
The documentation for gawk in the man page is not complete. Many GNU
programs have the full/better documentation in the info pages.
The documentation for your problem is accessible by the following command:
info gawk character list
It is the first paragraph in the info page.
2.4 Using Character Lists
=========================
Within a character list, a "range expression" consists of two
characters separated by a hyphen. It matches any single character that
sorts between the two characters, using the locale's collating sequence
and character set. For example, in the default C locale, `[a-dx-z]' is
equivalent to `[abcdxyz]'. Many locales sort characters in dictionary
order, and in these locales, `[a-dx-z]' is typically not equivalent to
`[abcdxyz]'; instead it might be equivalent to `[aBbCcDdxXyYz]', for
example. To obtain the traditional interpretation of bracket
expressions, you can use the C locale by setting the `LC_ALL'
environment variable to the value `C'.
Regards
Dirk
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