abbrev candidates feature

Author: ko1

lib/debug/abbrev_command.rb

@@ -32,6 +32,16 @@ def type
           nil
         end
       end
+
+      def candidates
+        @children.map{|c, n|
+          ss = n.candidates
+          ss.empty? ? c :
+          ss.map{|s|
+            c+s
+          }
+        }.flatten
+      end
     end
 
     # config: { type: [commands...], ... }
@@ -60,6 +70,7 @@ def search str, if_none = nil
           return if_none
         end
       end
+      yield trie.candidates.map{|s| str + s} if block_given?
       if_none
     end
   end

lib/debug/session.rb

@@ -786,7 +786,10 @@ def register_default_command
         end
 
         if sub
-          sub = info_subcommands_abbrev.search sub, :unknown
+          sub = info_subcommands_abbrev.search sub, :unknown do |candidates|
+            # note: unreached now
+            @ui.puts "Ambiguous command '#{sub}': #{candidates.join(' ')}"
+          end
         end
 
         case sub