 [ "a" ] [ "ab" "a(?=b)(?=b)" <regexp> first-match >string ] unit-test
 [ "a" ] [ "ba" "a(?<=b)(?<=b)" <regexp> first-match >string ] unit-test
 [ "a" ] [ "cab" "a(?=b)(?<=c)" <regexp> first-match >string ] unit-test
+
+[ 3 ] [ "foobar" "foo(?=bar)" <regexp> match-head ] unit-test
+[ f ] [ "foobxr" "foo(?=bar)" <regexp> match-head ] unit-test
+
+! Bug in parsing word
+[ t ] [ "a" R' a' matches?  ] unit-test
 
 ! [ "{Lower}" <regexp> ] [ invalid-range? ] must-fail-with
 

! [ t ] [ "fxxbar" "(?!foo).{3}bar" <regexp> matches? ] unit-test
! [ f ] [ "foobar" "(?!foo).{3}bar" <regexp> matches? ] unit-test

[ 3 ] [ "foobar" "foo(?=bar)" <regexp> match-head ] unit-test
[ f ] [ "foobxr" "foo(?=bar)" <regexp> match-head ] unit-test

! [ f ] [ "foobxr" "foo\\z" <regexp> match-head ] unit-test
! [ 3 ] [ "foo" "foo\\z" <regexp> match-head ] unit-test



! "a(?<=b)" <regexp> "caba" over first-match

! capture group 1: "aaaa"  2: ""
! "aaaa" "(a*)(a*)" <regexp> match*
! "aaaa" "(a*)(a+)" <regexp> match*
