diff --git a/src/cligen.cr b/src/cligen.cr
index 25d6d8c..354f06c 100644
--- a/src/cligen.cr
+++ b/src/cligen.cr
@@ -14,8 +14,8 @@ module CliGen
 
   ADDITIONAL_DEFAULT_FLAGS = [] of AdditionalDefaultFlag
 
-  def self.add_default_flag(short : String, long : String, description : String, &work : String -> )
-    raise "ERROR : add_default_flag : You must provide a description" unless description
+  def self.add_default_flag(short : String = "", long : String = "", description : String = "", &work : String -> )
+    raise "ERROR : add_default_flag : You must provide a description" if description.empty?
     ADDITIONAL_DEFAULT_FLAGS << AdditionalDefaultFlag.new(
       short: short,
       long: long,
@@ -64,7 +64,13 @@ module CliGen
     }
     
     CliGen::ADDITIONAL_DEFAULT_FLAGS.each do |flag|
-      {{parser}}.on(flag.short, flag.long, flag.description){|var| flag.work.call(var) }
+      if [ flag.short, flag.long ].all?(&.!= "")
+        {{parser}}.on(flag.short, flag.long, flag.description){|var| flag.work.call(var) }
+      elsif flag.short != ""
+        {{parser}}.on(flag.short, flag.description){|var| flag.work.call(var) }
+      elsif flag.long != ""
+        {{parser}}.on(flag.long, flag.description){|var| flag.work.call(var) }
+      end
     end
   end