The spec should be more explicit about which characters can be used as syntax chars in future directives

[bokand]

The list of characters that future directives may require escaping could vary according to the specification of that directive. The spec should be more explicit about the set of characters directives could use for that. E.g. TextDirective reserves ,, and - (in addition to the fragment-directive-globally reserved &). This would allow clients to be written in a way that parsing can't break in the future.

Note: This isn't currently an issue as there are no other directive types but could change in the future.