DB<1> $line = "\"quoted-text\" \cM\cJ"

  DB<2> x $line
0  "\"quoted-text\" \cM\cJ"

##</code><code>##

  DB<3> x $line =~ m/^(\s*)((?'quote'"?)[^\s"]*\g{quote})\s+(\[[^\]]*\]|)\s*$/
0  ''
1  '"quoted-text"'
2  '"'
3  ''

##</code><code>##

  DB<4> x $line =~ m/^(\s*)((?'quote'"?)[^\s"]*")\s+(\[[^\]]*\]|)\s*$/
0  ''
1  '"quoted-text"'
2  '"'
3  ''

##</code><code>##

  DB<5> x $line =~ m/^(\s*)(("?)[^\s"]*")\s+(\[[^\]]*\]|)\s*$/
0  ''
1  '"quoted-text"'
2  '"'
3  ''

##</code><code>##

  DB<6> x $line =~ m/^(\s*)("?[^\s"]*")\s+(\[[^\]]*\]|)\s*$/
0  ''
1  '"quoted-text"'
2  ''
3  ''