The format of the message catalog is as follow:
line : '#' comment # a comment | tag ':' definition # a tag definition | tag '=' tag # a link to another tag | '[' prefix ']' # a prefix to append to other tags prefix : tag # the tag to use as prefix | '*' # don't use a prefix definition : string # a string | string '\' definition # with posibility of continuation '\' tag : [a-zA-Z0-9_]+ |