Interacting with debugger commands at runtime from C++ #87

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1. slembcke commented on Nov 13, 2024

   

   slembcke

   on Nov 13, 2024

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   Hrm. Can you share some of your code maybe? While not a particularly interesting example, I do use this functionality to run the automated tests. There's not really much to it, it just just uses the overridden I/O to send commands from a list and check for expected output:
   https://github.com/slembcke/debugger.lua/blob/master/test/test_util.lua#L32
2. gsisinna commented on Nov 14, 2024

   

   gsisinna

   on Nov 14, 2024

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   Yes thank you, I'll try to give an idea of what I would like to achieve.

   I tried modifying the debugger.lua a bit to receive JSON packets as input instead of just writing from terminal and then pressing ENTER:

   local socket = require("socket")
   local json = require("json")
   
   print("Starting server...")
   local server = assert(socket.bind("127.0.0.1", 12345))
   print("Server started, waiting for client connection...")
   
   local client = server:accept()
   print("Client connected")
   
   local dbg
   
   ... (rest of the code)

   After this I modified the default functions to read and write using JSON encoding:

   local function dbg_write(str)
       print("dbg_write called with input: ", str)  -- Debug print to see the input
       local output = json.encode({ result = str })
       print("Encoded JSON: ", output)  -- Debug print to check the JSON encoding
       client:send(output .. "\n")
   end

   and

   local function dbg_read(prompt)
       print("dbg_read called with prompt: ", prompt)  -- Debug print to see the input prompt
       dbg.write(prompt)
       local input = client:receive()
       print("Received input: ", input)  -- Debug print to see the raw input received from the client
       local success, command = pcall(json.decode, input)
       if success then
           print("Decoded JSON: ", command)  -- Debug print to check the decoded JSON object
           return command
       else
           dbg_writeln(COLOR_RED.."Invalid JSON input"..COLOR_RESET)
           print("JSON decoding failed.")  -- Debug print to indicate failure
           return nil
       end
   end

   What I want to do now is match the already implemented methods (like step and locals) given the JSON data, and I was thinking on something like this:

   (... all debugger.lua code)
   
   -- Function to process and match commands
   local function process_command(command)
       -- Check if the command is a table with a 'cmd' attribute
       if type(command) == "table" and command.cmd then
           local func, arg = match_command(command.cmd)  -- Match the command
           if func then
               return func(arg)  -- Execute the command and return the result
           else
               return "Unknown command"  -- Return an error message for unrecognized commands
           end
       -- If the command is a string, directly match and process it
       elseif type(command) == "string" then
           local func, arg = match_command(command)  -- Match the command
           if func then
               return func(arg)  -- Execute the command and return the result
           else
               return "Unknown command"  -- Return an error message for unrecognized commands
           end
       end
   end
   
   -- Function to read and process commands in the main loop
   local function main_loop()
       while true do
           -- Read command from the client
           local command = dbg_read(GREEN_CARET)
           if command then
               -- Debug: print received command for inspection
               print("Received command: ", command)
   
               -- Process the command and get the result
               local result = process_command(command)
   
               -- Debug: print the result for inspection
               print("Result of command: ", result)
   
               -- Write the result back to the client
               dbg_writeln(result)
           end
       end
   end
   
   -- Start the main loop to continuously read commands and process them
   main_loop()
   
   return dbg

   I came to this conclusion after having not a little difficulty integrating c++-side interaction with the debugger shell in an automated way, so I moved to the Lua side. I would like to be able to have the debugger always listening for JSON commands without the need to interact with the shell.

   Thanks again!