add 'spec_line' to inline plotting
diff --git a/NAMESPACE b/NAMESPACE
index eda523b..b8ebdd2 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -46,6 +46,7 @@
 export(spec_font_size)
 export(spec_hist)
 export(spec_image)
+export(spec_line)
 export(spec_popover)
 export(spec_tooltip)
 export(text_spec)