gistfile1.cs

    var re = new Regex(string.Format(@"
(({0}                               # switch
(?<name>[_A-Za-z][_\w]*)            # name (any legal C# name)
({1}                                # sep + optional space
(((""(?<value>((\\"")|[^""])*)"")|  # match a double quoted value (escape "" with \)
('(?<value>((\\')|[^'])*)'))|       # match a single quoted value (escape ' with \)
(\{{(?<arrayval>[^\}}]*)\}})|       # list value (escaped for string.Format)
(?<value>\S+))                      # any single value
)?)|                                # sep option + list
(((""(?<value>((\\"")|[^""])*)"")|  # match a double quoted value (escape "" with \)
('(?<value>((\\')|[^'])*)'))|       # match a single quoted value (escape ' with \)
(\{{(?<arrayval>[^\}}]*)\}})|       # list value (escaped for string.Format)
(?<value>\S+)))*                    # any single value",
      Regex.Escape(prefix),
      seperator.Trim() == string.Empty ? @"\s+" : @"\s*" + Regex.Escape(seperator) + @"\s*"
      ),
      RegexOptions.Compiled | RegexOptions.ExplicitCapture | RegexOptions.IgnorePatternWhitespace);