handle explicit empty placeholders

1 files changed, 4 insertions, 1 deletions

diff --git a/usage.go b/usage.go
index a9f9844..43af31e 100644
--- a/usage.go
+++ b/usage.go
@@ -356,7 +356,10 @@ func (p *Parser) lookupCommand(path ...string) (*command, error) {
 }
 
 func synopsis(spec *spec, form string) string {
-	if spec.cardinality == zero {
+	// if the user omits the placeholder tag then we pick one automatically,
+	// but if the user explicitly specifies an empty placeholder then we
+	// leave out the placeholder in the help message
+	if spec.cardinality == zero || spec.placeholder == "" {
 		return form
 	}
 	return form + " " + spec.placeholder