When 'help' cannot find a command, produce additional help text that also points the user to the apropos and type lookup commands

This is useful in cases such as, e.g.

(lldb) help NSString
(the user meant type lookup)

or

(lldb) help kill
(the user is looking for process kill)

Fixes rdar://24868537

llvm-svn: 262271

1 files changed, 47 insertions, 15 deletions

diff --git a/lldb/source/Commands/CommandObjectHelp.cpp b/lldb/source/Commands/CommandObjectHelp.cpp
index 14d1ae5a..ad969db 100644
--- a/lldb/source/Commands/CommandObjectHelp.cpp
+++ b/lldb/source/Commands/CommandObjectHelp.cpp
@@ -24,6 +24,37 @@ using namespace lldb_private;
 // CommandObjectHelp
 //-------------------------------------------------------------------------
 
+void
+CommandObjectHelp::GenerateAdditionalHelpAvenuesMessage (Stream *s,
+                                                         const char* command,
+                                                         const char* prefix,
+                                                         const char* subcommand,
+                                                         bool include_apropos,
+                                                         bool include_type_lookup)
+{
+    if (s && command && *command)
+    {
+        s->Printf("'%s' is not a known command.\n", command);
+        if (prefix && *prefix)
+        {
+            s->Printf("Try '%shelp' to see a current list of commands.\n", prefix);
+        }
+        else
+        {
+            s->PutCString("Try 'help' to see a current list of commands.\n");
+        }
+        
+        if (include_apropos)
+        {
+            s->Printf("Try 'apropos %s' for a list of related commands.\n", subcommand ? subcommand : command);
+        }
+        if (include_type_lookup)
+        {
+            s->Printf("Try 'type lookup %s' for information on types, methods, functions, modules, etc.", subcommand ? subcommand : command);
+        }
+    }
+}
+
 CommandObjectHelp::CommandObjectHelp (CommandInterpreter &interpreter) :
     CommandObjectParsed (interpreter,
                          "help",
@@ -92,9 +123,10 @@ CommandObjectHelp::DoExecute (Args& command, CommandReturnObject &result)
             CommandObject *sub_cmd_obj = cmd_obj;
             // Loop down through sub_command dictionaries until we find the command object that corresponds
             // to the help command entered.
+            std::string sub_command;
             for (size_t i = 1; i < argc && all_okay; ++i)
             {
-                std::string sub_command = command.GetArgumentAtIndex(i);
+                sub_command = command.GetArgumentAtIndex(i);
                 matches.Clear();
                 if (! sub_cmd_obj->IsMultiwordObject ())
                 {
@@ -133,21 +165,22 @@ CommandObjectHelp::DoExecute (Args& command, CommandReturnObject &result)
                 }
                 else if (!sub_cmd_obj)
                 {
-                    result.AppendErrorWithFormat("'%s' is not a known command.\n"
-                                                 "Try '%shelp' to see a current list of commands.\n",
-                                                 cmd_string.c_str(),
-                                                 m_interpreter.GetCommandPrefix());
+                    StreamString error_msg_stream;
+                    GenerateAdditionalHelpAvenuesMessage(&error_msg_stream,
+                                                         cmd_string.c_str(),
+                                                         m_interpreter.GetCommandPrefix(),
+                                                         sub_command.c_str());
+                    result.AppendErrorWithFormat("%s",error_msg_stream.GetData());
                     result.SetStatus (eReturnStatusFailed);
                     return false;
                 }
                 else
                 {
-                    result.GetOutputStream().Printf("'%s' is not a known command.\n"
-                                                   "Try '%shelp' to see a current list of commands.\n"
-                                                    "The closest match is '%s'. Help on it follows.\n\n",
-                                                   cmd_string.c_str(),
-                                                   m_interpreter.GetCommandPrefix(),
-                                                   sub_cmd_obj->GetCommandName());
+                    GenerateAdditionalHelpAvenuesMessage(&result.GetOutputStream(),
+                                                         cmd_string.c_str(),
+                                                         m_interpreter.GetCommandPrefix(),
+                                                         sub_command.c_str());
+                    result.GetOutputStream().Printf("\nThe closest match is '%s'. Help on it follows.\n\n", sub_cmd_obj->GetCommandName());
                 }
             }
             
@@ -182,10 +215,9 @@ CommandObjectHelp::DoExecute (Args& command, CommandReturnObject &result)
             }
             else
             {
-                result.AppendErrorWithFormat 
-                    ("'%s' is not a known command.\nTry '%shelp' to see a current list of commands.\n",
-                     command.GetArgumentAtIndex(0),
-                     m_interpreter.GetCommandPrefix());
+                StreamString error_msg_stream;
+                GenerateAdditionalHelpAvenuesMessage(&error_msg_stream, command.GetArgumentAtIndex(0), m_interpreter.GetCommandPrefix());
+                result.AppendErrorWithFormat("%s",error_msg_stream.GetData());
                 result.SetStatus (eReturnStatusFailed);
             }
         }