#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# simple expansion -- no problem, it's quote_string_for_globbing that was flawed
c=$'\177'
r="\\$c"

recho $r

# first, match some regular expressions containing ^A, ^G, ^?
[[ $'\001' =~ $'\001' ]] ; echo $?
[[ $'\001' =~ $'\\\001' ]] ; echo $?
[[ $'\001' =~ $'\\[\001]' ]] ; echo $?

[[ $'\a' =~ $'\a' ]] ; echo $?
[[ $'\a' =~ $'\\\a' ]]  ; echo $?
[[ $'\a' =~ $'\\[\a]' ]] ; echo $?

[[ $'\177' =~ $'\177' ]] ; echo $?
[[ $'\177' =~ $'\\\177' ]] ; echo $?
[[ $'\177' =~ $'\\[\177]' ]] ; echo $?

# Now let's try it with variables expanding to those values
for c in $'\001' $'\a' $'\177' ; do
	for r in "$c" "\\$c" "\\[$c]"; do
		[[ $c =~ $r ]];
		printf '[[ %q =~ %q ]] -> %d\n' "$c" "$r" "$?";
	done;
	printf %s\\n ---
done

# try again with literals

[[ '
' =~ $'
' ]] ; echo $?
[[ '
' =~ '\
' ]] ; echo $?
[[ '
' =~ '\[
]' ]] ; echo $?

[[ '' =~ '' ]] ; echo $?
[[ '' =~ '\' ]]  ; echo $?
[[ '' =~ '\[]' ]] ; echo $?

[[ '' =~ $'' ]] ; echo $?
[[ '' =~ '\' ]] ; echo $?
[[ '' =~ '\[]' ]] ; echo $?

# more expansions, but with literal non-special characters
[[ x =~ \x ]] ; echo $?
[[ x =~ \\x ]] ; echo $?

bs='\'
[[ x =~ ${bs}x ]] ; echo $?

[[ x =~ $'\\'x ]] ; echo $?
[[ x =~ '\'x ]] ; echo $?

v='a\-b'
[[ a-b =~ ${v} ]] ; echo $?
[[ a-b =~ a\-b ]]; echo $?
[[ a-b =~ a${bs}-b ]]; echo $?
[[ a-b =~ a\\-b ]] ; echo $?
[[ a-b =~ "a\-b" ]] ; echo $?

c=$'\001'

recho $c "$c"

[[ $c == $c ]] && echo ok 1
[[ $c =~ $c ]] && echo ok 2
[[ $c =~ \\$c ]] || echo ok 3
[[ $c =~ \\"$c" ]] || echo ok 4

[[ $c =~ "\\"$c ]] || echo ok 5
[[ $c =~ '\'$c ]] || echo ok 6

[[ $c =~ "\\""$c" ]] || echo ok 7
[[ $c =~ '\'"$c" ]] || echo ok 8