1 files changed, 12 insertions, 0 deletions
diff --git a/internal/cond/types.go b/internal/cond/types.go
index 81c2f45..9455f63 100644
--- a/internal/cond/types.go
+++ b/internal/cond/types.go
@@ -93,6 +93,18 @@ type node struct {
 	dirs []string
 }
 
+// NameGroups returns the number of capture groups of every name test in the
+// condition that can ever supply captures, in compile order: a name test
+// nested inside and/or counts however deep, but one inside a not does not
+// (B1) - it can never be the source of Result.Captures, so it must not be
+// asked to justify a rule's use of {N} either. Empty when the rule has no
+// such name test.
+func (c *Cond) NameGroups() []int {
+	var out []int
+	collectNameGroups(c.root, &out)
+	return out
+}
+
 // groups maps a (type ...) group name to the extensions it expands to,
 // spec Appendix A.
 var groups = map[string][]string{