diff --git a/kong.go b/kong.go
index 5c06d55..6fdfa47 100644
--- a/kong.go
+++ b/kong.go
@@ -8,9 +8,7 @@ import (
 	"strings"
 )
 
-type Error struct {
-	msg string
-}
+type Error struct{ msg string }
 
 func (e Error) Error() string { return e.msg }
 
diff --git a/kong_test.go b/kong_test.go
index 10e4894..9abbe54 100644
--- a/kong_test.go
+++ b/kong_test.go
@@ -50,7 +50,7 @@ func TestBranchingArgument(t *testing.T) {
 				Flag   int      `help:""`
 				Delete struct{} `help:""`
 				Rename struct {
-					To string
+					To string `help:""`
 				} `help:""`
 			} `arg:"" help:""`
 		} `help:"Manage users."`
diff --git a/scanner.go b/scanner.go
index e653988..08e7476 100644
--- a/scanner.go
+++ b/scanner.go
@@ -57,6 +57,14 @@ func (t Token) IsValue() bool {
 		(t.Type == UntypedToken && !strings.HasPrefix(t.Value, "-"))
 }
 
+// Scanner is a stack-based scanner over command-line tokens.
+//
+// Initially all tokens are untyped. As the parser consumes tokens it assigns types, splits tokens, and pushes them back
+// onto the stream.
+//
+// For example, the token "--foo=bar" will be split into the following by the parser:
+//
+// 		[{FlagToken, "foo"}, {FlagValueToken, "bar"}]
 type Scanner struct {
 	args []Token
 }