There is still ambiguity with a.b and a(b).
If there is white space before . it is an optional break; else it is a path separator.
If there is white space before ( it starts a parenthesized expression; else it starts a parameter list
This needs to be implemented. For now, [a .] is not accepted by the parser.
As noted on the Syntax documentation page:
This needs to be implemented. For now, [a .] is not accepted by the parser.