Re: input foo, output '[F|f][O|o][O|o]'?

["TJ Luoma" <luomat@gmail.com>]

On 1 Jul 2013, at 14:44, ZyX wrote:

> I do not think you will find a way to do this. All regex engines 
> (precisely, programs that are using them) I know support a way to set 
> case sensitivity for the whole regular expression and some support 
> toggling this for a part of regular expression. In grep this is an -i 
> switch, for vim it is either /i or \c/\C, for sed this is /i, for PCRE 
> and perl this is additionally (?i) "atom" (additionally to other ways 
> of toggling the behavior which are highly dependent on programs 
> embedding PCRE; for perl this is usual /i flag). Even zsh globs do 
> support (#i).

Phil Pennock's version worked great:

% foo=CrashPlan
% for c in ${(s::)foo}; do print -n "[${(U)c}|${(L)c}]";done; print
[C|c][R|r][A|a][S|s][H|h][P|p][L|l][A|a][N|n]
%


> By the way, what regex engine is your output for? Any I am aware of 
> parse "[N|n]" as "either one of three characters: N, n, or pipe".

Really? I can think of several that support it. Maybe it's because I'm 
old enough to remember when a lot of these utilities didn't have 'ignore 
case'

% echo "foo\nbar\nbat" | egrep -v '[F|f]'
bar
bat

% echo "foo\nbar\nbat" | sed 's#[F|f][O|o][O|o]#XXX#g'
XXX
bar
bat

You can also use it for matching case/esac :

case "$i" in
	[C|c][R|r][A|a][S|s][H|h][P|p][L|l][A|a][N|n])
			echo "matched crashplan"
	;;

	*)
			echo "No Match"
	;;

esac


> I am also assuming XY problem here: what for do you need such 
> conversion? You should consider lowercasing the tested string if 
> nothing like -i is available.

It's for use with the AddDescription directive for .htaccess which (from 
what I understand) takes its case sensitivity from the underlying 
filesystem when matching filenames. There's no "ignore case" flag or 
anything else that I can use with it, so my only option (at least, the 
only one I can think of) is the one that I suggested. For example, if I 
wanted to add this for any files which start with 'BBEdit' (case 
insensitive) this is what I'd need to use:

	AddDescription "<a href='http://barebones.com/bbedit'>A text editor 
that doesn't suck</a>" [B|b][B|b][E|e][D|d][I|i][T|t]*

I verified that it works, but typing that stuff manually is tedious and 
highly error prone, which made it the perfect place for a shell script 
:-)

TjL