Constructions not yet covered by the test suite ...

Operator	Covered	Notes
--------	-------	-----
.   dot		y
..  range	y	char range
alnum		y
alpha		y
ascii		y
cl		y	general char class, fused char choice
control		y
ddigit		y
digit		y
graph		y
lower		y
n   nonterminal	y
printable	y
punct		y
space		y
str		y	fused char sequence
t   terminal	y	general terminal char
upper		y
wordchar	y
xdigit		y
/   choice	y
x   sequence	y
*   repeat0	y	kleene
+   repeat1	y	pos.kleene
?   optional	y
!  notahead		lookahead predicate, assert non-match
--------	-------	-----
&  ahead		lookahead predicate, assert match
--------	-------	-----
epsilon		n	internal, not directly accessible
			only indirectly through "?"
--------	-------