Add Lite Debugger plugin

   Upstream https://github.com/slembcke/debugger.lua
   with changes to allow for native breakpoints

2 files changed, 671 insertions, 0 deletions

diff --git a/manifest.json b/manifest.json
index e919107..a6e3f03 100644
--- a/manifest.json
+++ b/manifest.json
@@ -113,6 +113,13 @@
       "mod_version": "3"
     },
     {
+      "description": "Debug Lite-XL's Lua VM interactively",
+      "version": "0.1",
+      "path": "plugins/lite-debugger.lua",
+      "id": "lite-debugger",
+      "mod_version": "3"
+    },
+    {
       "description": "Provides a debugger integration, with pluggable backends. Currently supports only gdb. *([screenshot](https://raw.githubusercontent.com/adamharrison/lite-xl-ide/main/screenshots/debugger.png))*",
       "version": "0.1",
       "remote": "https://github.com/adamharrison/lite-xl-ide.git:445345f2b25898404879dacbd7709f8a7c7b0795",
diff --git a/plugins/lite-debugger.lua b/plugins/lite-debugger.lua
new file mode 100644
index 0000000..926f168
--- /dev/null
+++ b/plugins/lite-debugger.lua
@@ -0,0 +1,664 @@
+-- mod-version:3
+
+local command = require "core.command"
+local core = require "core"
+
+--[[
+   Upstream https://github.com/slembcke/debugger.lua
+   with changes to allow for breakpoints for better debugging
+
+   Copyright (c) 2020 Scott Lembcke and Howling Moon Software
+   
+   Permission is hereby granted, free of charge, to any person obtaining a copy
+   of this software and associated documentation files (the "Software"), to deal
+   in the Software without restriction, including without limitation the rights
+   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+   copies of the Software, and to permit persons to whom the Software is
+   furnished to do so, subject to the following conditions:
+   
+   The above copyright notice and this permission notice shall be included in
+   all copies or substantial portions of the Software.
+   
+   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+   SOFTWARE.
+   
+   TODO:
+   * Print short function arguments as part of stack location.
+   * Properly handle being reentrant due to coroutines.
+]]
+
+local dbg
+
+-- Use ANSI color codes in the prompt by default.
+local COLOR_GRAY = ""
+local COLOR_RED = ""
+local COLOR_BLUE = ""
+local COLOR_YELLOW = ""
+local COLOR_RESET = ""
+local GREEN_CARET = " => "
+
+local function pretty(obj, max_depth)
+   if max_depth == nil then max_depth = dbg.pretty_depth end
+   
+   -- Returns true if a table has a __tostring metamethod.
+   local function coerceable(tbl)
+      local meta = getmetatable(tbl)
+      return (meta and meta.__tostring)
+   end
+   
+   local function recurse(obj, depth)
+      if type(obj) == "string" then
+         -- Dump the string so that escape sequences are printed.
+         return string.format("%q", obj)
+      elseif type(obj) == "table" and depth < max_depth and not coerceable(obj) then
+         local str = "{"
+         
+         for k, v in pairs(obj) do
+            local pair = pretty(k, 0).." = "..recurse(v, depth + 1)
+            str = str..(str == "{" and pair or ", "..pair)
+         end
+         
+         return str.."}"
+      else
+         -- tostring() can fail if there is an error in a __tostring metamethod.
+         local success, value = pcall(function() return tostring(obj) end)
+         return (success and value or "<!!error in __tostring metamethod!!>")
+      end
+   end
+   
+   return recurse(obj, 0)
+end
+
+-- The stack level that cmd_* functions use to access locals or info
+-- The structure of the code very carefully ensures this.
+local CMD_STACK_LEVEL = 6
+
+-- Location of the top of the stack outside of the debugger.
+-- Adjusted by some debugger entrypoints.
+local stack_top = 0
+
+-- The current stack frame index.
+-- Changed using the up/down commands
+local stack_inspect_offset = 0
+
+-- LuaJIT has an off by one bug when setting local variables.
+local LUA_JIT_SETLOCAL_WORKAROUND = 0
+
+-- Default dbg.read function
+local function dbg_read(prompt)
+   dbg.write(prompt)
+   io.flush()
+   return io.read()
+end
+
+-- Default dbg.write function
+local function dbg_write(str)
+   io.write(str)
+end
+
+local function dbg_writeln(str, ...)
+   if select("#", ...) == 0 then
+      dbg.write((str or "<NULL>").."\n")
+   else
+      dbg.write(string.format(str.."\n", ...))
+   end
+end
+
+local function format_loc(file, line) return COLOR_BLUE..file..COLOR_RESET..":"..COLOR_YELLOW..line..COLOR_RESET end
+local function format_stack_frame_info(info)
+   local filename = info.source:match("@(.*)")
+   local source = filename and dbg.shorten_path(filename) or info.short_src
+   local namewhat = (info.namewhat == "" and "chunk at" or info.namewhat)
+   local name = (info.name and "'"..COLOR_BLUE..info.name..COLOR_RESET.."'" or format_loc(source, info.linedefined))
+   return format_loc(source, info.currentline).." in "..namewhat.." "..name
+end
+
+local repl
+
+-- Return false for stack frames without source,
+-- which includes C frames, Lua bytecode, and `loadstring` functions
+local function frame_has_line(info) return info.currentline >= 0 end
+
+local function hook_factory(repl_threshold)
+   return function(offset, reason)
+      return function(event, _)
+         -- Skip events that don't have line information.
+         if not frame_has_line(debug.getinfo(2)) then return end
+         
+         -- Tail calls are specifically ignored since they also will have tail returns to balance out.
+         if event == "call" then
+            offset = offset + 1
+         elseif event == "return" and offset > repl_threshold then
+            offset = offset - 1
+         elseif event == "line" and offset <= repl_threshold then
+            repl(reason)
+         end
+      end
+   end
+end
+
+local hook_step = hook_factory(1)
+local hook_next = hook_factory(0)
+local hook_finish = hook_factory(-1)
+local hook_break = hook_factory(1)
+
+-- Create a table of all the locally accessible variables.
+-- Globals are not included when running the locals command, but are when running the print command.
+local function local_bindings(offset, include_globals)
+   local level = offset + stack_inspect_offset + CMD_STACK_LEVEL
+   local func = debug.getinfo(level).func
+   local bindings = {}
+   
+   -- Retrieve the upvalues
+   do local i = 1; while true do
+      local name, value = debug.getupvalue(func, i)
+      if not name then break end
+      bindings[name] = value
+      i = i + 1
+   end end
+   
+   -- Retrieve the locals (overwriting any upvalues)
+   do local i = 1; while true do
+      local name, value = debug.getlocal(level, i)
+      if not name then break end
+      bindings[name] = value
+      i = i + 1
+   end end
+   
+   -- Retrieve the varargs (works in Lua 5.2 and LuaJIT)
+   local varargs = {}
+   do local i = 1; while true do
+      local name, value = debug.getlocal(level, -i)
+      if not name then break end
+      varargs[i] = value
+      i = i + 1
+   end end
+   if #varargs > 0 then bindings["..."] = varargs end
+   
+   if include_globals then
+      -- In Lua 5.2, you have to get the environment table from the function's locals.
+      local env = (_VERSION <= "Lua 5.1" and getfenv(func) or bindings._ENV)
+      return setmetatable(bindings, {__index = env or _G})
+   else
+      return bindings
+   end
+end
+
+-- Used as a __newindex metamethod to modify variables in cmd_eval().
+local function mutate_bindings(_, name, value)
+   local FUNC_STACK_OFFSET = 3 -- Stack depth of this function.
+   local level = stack_inspect_offset + FUNC_STACK_OFFSET + CMD_STACK_LEVEL
+   
+   -- Set a local.
+   do local i = 1; repeat
+      local var = debug.getlocal(level, i)
+      if name == var then
+         dbg_writeln(COLOR_YELLOW.."debugger.lua"..GREEN_CARET.."Set local variable "..COLOR_BLUE..name..COLOR_RESET)
+         return debug.setlocal(level + LUA_JIT_SETLOCAL_WORKAROUND, i, value)
+      end
+      i = i + 1
+   until var == nil end
+   
+   -- Set an upvalue.
+   local func = debug.getinfo(level).func
+   do local i = 1; repeat
+      local var = debug.getupvalue(func, i)
+      if name == var then
+         dbg_writeln(COLOR_YELLOW.."debugger.lua"..GREEN_CARET.."Set upvalue "..COLOR_BLUE..name..COLOR_RESET)
+         return debug.setupvalue(func, i, value)
+      end
+      i = i + 1
+   until var == nil end
+   
+   -- Set a global.
+   dbg_writeln(COLOR_YELLOW.."debugger.lua"..GREEN_CARET.."Set global variable "..COLOR_BLUE..name..COLOR_RESET)
+   _G[name] = value
+end
+
+-- Compile an expression with the given variable bindings.
+local function compile_chunk(block, env)
+   local source = "debugger.lua REPL"
+   local chunk = nil
+   
+   if _VERSION <= "Lua 5.1" then
+      chunk = loadstring(block, source)
+      if chunk then setfenv(chunk, env) end
+   else
+      -- The Lua 5.2 way is a bit cleaner
+      chunk = load(block, source, "t", env)
+   end
+   
+   if not chunk then dbg_writeln(COLOR_RED.."Error: Could not compile block:\n"..COLOR_RESET..block) end
+   return chunk
+end
+
+local SOURCE_CACHE = {}
+
+local function where(info, context_lines)
+   local source = SOURCE_CACHE[info.source]
+   if not source then
+      source = {}
+      local filename = info.source:match("@(.*)")
+      if filename then
+         pcall(function() for line in io.lines(filename) do table.insert(source, line) end end)
+      elseif info.source then
+         for line in info.source:gmatch("(.-)\n") do table.insert(source, line) end
+      end
+      SOURCE_CACHE[info.source] = source
+   end
+   
+   if source and source[info.currentline] then
+      for i = info.currentline - context_lines, info.currentline + context_lines do
+         local tab_or_caret = (i == info.currentline and  GREEN_CARET or "    ")
+         local line = source[i]
+         if line then dbg_writeln(COLOR_GRAY.."% 4d"..tab_or_caret.."%s", i, line) end
+      end
+   else
+      dbg_writeln(COLOR_RED.."Error: Source not available for "..COLOR_BLUE..info.short_src);
+   end
+   
+   return false
+end
+
+-- Wee version differences
+local unpack = table.unpack
+local pack = function(...) return {n = select("#", ...), ...} end
+
+local break_funcs = {}
+
+local function cmd_break(func_name)
+   table.insert(break_funcs, func_name)
+   return false
+end
+
+local function cmd_delete(index)
+   index = tonumber(index)
+   if index > #break_funcs then
+      dbg_writeln(COLOR_RED.."Error:"..COLOR_RESET.." no breakpoint "..index)
+   else
+      table.remove(break_funcs, index)
+   end
+   return false
+end
+
+local function cmd_step()
+   stack_inspect_offset = stack_top
+   return true, hook_step
+end
+
+local function cmd_next()
+   stack_inspect_offset = stack_top
+   return true, hook_next
+end
+
+local function cmd_finish()
+   local offset = stack_top - stack_inspect_offset
+   stack_inspect_offset = stack_top
+   return true, offset < 0 and hook_factory(offset - 1) or hook_finish
+end
+
+local function cmd_print(expr)
+   local env = local_bindings(1, true)
+   local chunk = compile_chunk("return "..expr, env)
+   if chunk == nil then return false end
+   
+   -- Call the chunk and collect the results.
+   local results = pack(pcall(chunk, unpack(rawget(env, "...") or {})))
+   
+   -- The first result is the pcall error.
+   if not results[1] then
+      dbg_writeln(COLOR_RED.."Error:"..COLOR_RESET.." "..results[2])
+   else
+      local output = ""
+      for i = 2, results.n do
+         output = output..(i ~= 2 and ", " or "")..pretty(results[i])
+      end
+      
+      if output == "" then output = "<no result>" end
+      dbg_writeln(COLOR_BLUE..expr.. GREEN_CARET..output)
+   end
+   
+   return false
+end
+
+local function cmd_eval(code)
+   local env = local_bindings(1, true)
+   local mutable_env = setmetatable({}, {
+      __index = env,
+      __newindex = mutate_bindings,
+   })
+   
+   local chunk = compile_chunk(code, mutable_env)
+   if chunk == nil then return false end
+   
+   -- Call the chunk and collect the results.
+   local success, err = pcall(chunk, unpack(rawget(env, "...") or {}))
+   if not success then
+      dbg_writeln(COLOR_RED.."Error:"..COLOR_RESET.." "..tostring(err))
+   end
+   
+   return false
+end
+
+local function cmd_down()
+   local offset = stack_inspect_offset
+   local info
+   
+   repeat -- Find the next frame with a file.
+      offset = offset + 1
+      info = debug.getinfo(offset + CMD_STACK_LEVEL)
+   until not info or frame_has_line(info)
+   
+   if info then
+      stack_inspect_offset = offset
+      dbg_writeln("Inspecting frame: "..format_stack_frame_info(info))
+      if tonumber(dbg.auto_where) then where(info, dbg.auto_where) end
+   else
+      info = debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL)
+      dbg_writeln("Already at the bottom of the stack.")
+   end
+   
+   return false
+end
+
+local function cmd_up()
+   local offset = stack_inspect_offset
+   local info
+   
+   repeat -- Find the next frame with a file.
+      offset = offset - 1
+      if offset < stack_top then info = nil; break end
+      info = debug.getinfo(offset + CMD_STACK_LEVEL)
+   until frame_has_line(info)
+   
+   if info then
+      stack_inspect_offset = offset
+      dbg_writeln("Inspecting frame: "..format_stack_frame_info(info))
+      if tonumber(dbg.auto_where) then where(info, dbg.auto_where) end
+   else
+      info = debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL)
+      dbg_writeln("Already at the top of the stack.")
+   end
+   
+   return false
+end
+
+local function cmd_where(context_lines)
+   local info = debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL)
+   return (info and where(info, tonumber(context_lines) or 5))
+end
+
+local function cmd_trace()
+   dbg_writeln("Inspecting frame %d", stack_inspect_offset - stack_top)
+   local i = 0; while true do
+      local info = debug.getinfo(stack_top + CMD_STACK_LEVEL + i)
+      if not info then break end
+      
+      local is_current_frame = (i + stack_top == stack_inspect_offset)
+      local tab_or_caret = (is_current_frame and  GREEN_CARET or "    ")
+      dbg_writeln(COLOR_GRAY.."% 4d"..COLOR_RESET..tab_or_caret.."%s", i, format_stack_frame_info(info))
+      i = i + 1
+   end
+   
+   return false
+end
+
+local function cmd_locals()
+   local bindings = local_bindings(1, false)
+   
+   -- Get all the variable binding names and sort them
+   local keys = {}
+   for k, _ in pairs(bindings) do table.insert(keys, k) end
+   table.sort(keys)
+   
+   for _, k in ipairs(keys) do
+      local v = bindings[k]
+      
+      -- Skip the debugger object itself, "(*internal)" values, and Lua 5.2's _ENV object.
+      if not rawequal(v, dbg) and k ~= "_ENV" and not k:match("%(.*%)") then
+         dbg_writeln("  "..COLOR_BLUE..k.. GREEN_CARET..pretty(v))
+      end
+   end
+   
+   return false
+end
+
+local function cmd_help()
+   dbg.write(""
+      .. COLOR_BLUE.."  <return>"..GREEN_CARET.."re-run last command\n"
+      .. COLOR_BLUE.."  c"..COLOR_YELLOW.."(ontinue)"..GREEN_CARET.."continue execution\n"
+      .. COLOR_BLUE.."  b"..COLOR_YELLOW.."(reak) "..COLOR_BLUE.."[[file:]function]"..GREEN_CARET.."set breakpoint at specified function\n"
+      .. COLOR_BLUE.."  d"..COLOR_YELLOW.."(elete) "..COLOR_BLUE.."[index]"..GREEN_CARET.."remove breakpoint\n"
+      .. COLOR_BLUE.."  s"..COLOR_YELLOW.."(tep)"..GREEN_CARET.."step forward by one line (into functions)\n"
+      .. COLOR_BLUE.."  n"..COLOR_YELLOW.."(ext)"..GREEN_CARET.."step forward by one line (skipping over functions)\n"
+      .. COLOR_BLUE.."  f"..COLOR_YELLOW.."(inish)"..GREEN_CARET.."step forward until exiting the current function\n"
+      .. COLOR_BLUE.."  u"..COLOR_YELLOW.."(p)"..GREEN_CARET.."move up the stack by one frame\n"
+      .. COLOR_BLUE.."  d"..COLOR_YELLOW.."(own)"..GREEN_CARET.."move down the stack by one frame\n"
+      .. COLOR_BLUE.."  w"..COLOR_YELLOW.."(here) "..COLOR_BLUE.."[line count]"..GREEN_CARET.."print source code around the current line\n"
+      .. COLOR_BLUE.."  e"..COLOR_YELLOW.."(val) "..COLOR_BLUE.."[statement]"..GREEN_CARET.."execute the statement\n"
+      .. COLOR_BLUE.."  p"..COLOR_YELLOW.."(rint) "..COLOR_BLUE.."[expression]"..GREEN_CARET.."execute the expression and print the result\n"
+      .. COLOR_BLUE.."  t"..COLOR_YELLOW.."(race)"..GREEN_CARET.."print the stack trace\n"
+      .. COLOR_BLUE.."  l"..COLOR_YELLOW.."(ocals)"..GREEN_CARET.."print the function arguments, locals and upvalues.\n"
+      .. COLOR_BLUE.."  h"..COLOR_YELLOW.."(elp)"..GREEN_CARET.."print this message\n"
+      .. COLOR_BLUE.."  q"..COLOR_YELLOW.."(uit)"..GREEN_CARET.."halt execution\n"
+   )
+   return false
+end
+
+local last_cmd = false
+local abc = 0
+
+local function in_array(tab, val)
+    for index, value in ipairs(tab) do
+        if value == val then
+            return true
+        end
+    end
+
+    return false
+end
+
+local function split(inputstr, sep)
+   if sep == nil then
+          sep = "%s"
+   end
+   local t={}
+   for str in string.gmatch(inputstr, "([^"..sep.."]+)") do
+          table.insert(t, str)
+   end
+   return t
+end
+
+local function debug_hook(offset, reason)
+   local function trace (event, line)
+      if event == "line" then
+         return
+      end
+
+      local s = debug.getinfo(2)
+
+      if #s.namewhat > 0 then
+         local i = split(s.short_src, "/")
+         local long_name = i[#i]..":"..s.name
+
+         if in_array(break_funcs, long_name) or in_array(break_funcs, s.name) then
+            offset = offset - 1
+            repl(reason)
+         end
+      end
+   end
+   return trace
+end
+debug.sethook(debug_hook(0), "crl")
+
+local function cmd_continue()
+
+   return true, debug_hook
+end
+
+local commands = {
+   ["^c$"] = cmd_continue,
+   ["^b%s+(.*)$"] = cmd_break,
+   ["^d%s+(%d*)$"] = cmd_delete,
+   ["^s$"] = cmd_step,
+   ["^n$"] = cmd_next,
+   ["^f$"] = cmd_finish,
+   ["^p%s+(.*)$"] = cmd_print,
+   ["^e%s+(.*)$"] = cmd_eval,
+   ["^u$"] = cmd_up,
+   ["^d$"] = cmd_down,
+   ["^w%s*(%d*)$"] = cmd_where,
+   ["^t$"] = cmd_trace,
+   ["^l$"] = cmd_locals,
+   ["^h$"] = cmd_help,
+   ["^q$"] = function() dbg.exit(0); return true end,
+}
+
+local function match_command(line)
+   for pat, func in pairs(commands) do
+      -- Return the matching command and capture argument.
+      if line:find(pat) then return func, line:match(pat) end
+   end
+end
+
+-- Run a command line
+-- Returns true if the REPL should exit and the hook function factory
+local function run_command(line)
+   -- GDB/LLDB exit on ctrl-d
+   if line == nil then dbg.exit(1); return true end
+   
+   -- Re-execute the last command if you press return.
+   if line == "" then line = last_cmd or "h" end
+   
+   local command, command_arg = match_command(line)
+   if command then
+      last_cmd = line
+      -- unpack({...}) prevents tail call elimination so the stack frame indices are predictable.
+      return unpack({command(command_arg)})
+   elseif dbg.auto_eval then
+      return unpack({cmd_eval(line)})
+   else
+      dbg_writeln(COLOR_RED.."Error:"..COLOR_RESET.." command '%s' not recognized.\nType 'h' and press return for a command list.", line)
+      return false
+   end
+end
+
+repl = function(reason)
+   -- Skip frames without source info.
+   while not frame_has_line(debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL - 3)) do
+      stack_inspect_offset = stack_inspect_offset + 1
+   end
+   
+   local info = debug.getinfo(stack_inspect_offset + CMD_STACK_LEVEL - 3)
+   reason = reason and (COLOR_YELLOW.."break via "..COLOR_RED..reason..GREEN_CARET) or ""
+   dbg_writeln(reason..format_stack_frame_info(info))
+   
+   if tonumber(dbg.auto_where) then where(info, dbg.auto_where) end
+   
+   repeat
+      local success, done, hook = pcall(run_command, dbg.read(COLOR_RED.."debugger.lua> "..COLOR_RESET))
+      if success then
+         debug.sethook(hook and hook(0), "crl")
+      else
+         local message = COLOR_RED.."INTERNAL DEBUGGER.LUA ERROR. ABORTING\n:"..COLOR_RESET.." "..done
+         dbg_writeln(message)
+         error(message)
+      end
+   until done
+end
+
+-- Make the debugger object callable like a function.
+dbg = setmetatable({}, {
+   __call = function(_, condition, top_offset, source)
+      if condition then return end
+      
+      top_offset = (top_offset or 0)
+      stack_inspect_offset = top_offset
+      stack_top = top_offset
+      
+      debug.sethook(hook_next(1, source or "dbg()"), "crl")
+      return
+   end,
+})
+
+-- Expose the debugger's IO functions.
+dbg.read = dbg_read
+dbg.write = dbg_write
+dbg.shorten_path = function (path) return path end
+dbg.exit = function(err) os.exit(err) end
+
+dbg.writeln = dbg_writeln
+
+dbg.pretty_depth = 3
+dbg.pretty = pretty
+dbg.pp = function(value, depth) dbg_writeln(pretty(value, depth)) end
+
+dbg.auto_where = false
+dbg.auto_eval = false
+
+local lua_error, lua_assert = error, assert
+
+-- Works like error(), but invokes the debugger.
+function dbg.error(err, level)
+   level = level or 1
+   dbg_writeln(COLOR_RED.."ERROR: "..COLOR_RESET..pretty(err))
+   dbg(false, level, "dbg.error()")
+   
+   lua_error(err, level)
+end
+
+-- Works like assert(), but invokes the debugger on a failure.
+function dbg.assert(condition, message)
+   if not condition then
+      dbg_writeln(COLOR_RED.."ERROR:"..COLOR_RESET..message)
+      dbg(false, 1, "dbg.assert()")
+   end
+   
+   return lua_assert(condition, message)
+end
+
+-- Works like pcall(), but invokes the debugger on an error.
+function dbg.call(f, ...)
+   return xpcall(f, function(err)
+      dbg_writeln(COLOR_RED.."ERROR: "..COLOR_RESET..pretty(err))
+      dbg(false, 1, "dbg.call()")
+      
+      return err
+   end, ...)
+end
+
+-- Error message handler that can be used with lua_pcall().
+function dbg.msgh(...)
+   if debug.getinfo(2) then
+      dbg_writeln(COLOR_RED.."ERROR: "..COLOR_RESET..pretty(...))
+      dbg(false, 1, "dbg.msgh()")
+   else
+      dbg_writeln(COLOR_RED.."debugger.lua: "..COLOR_RESET.."Error did not occur in Lua code. Execution will continue after dbg_pcall().")
+   end
+   
+   return ...
+end
+
+-- Conditionally enable color support.
+local color_maybe_supported = (os.getenv("TERM") and os.getenv("TERM") ~= "dumb")
+if color_maybe_supported and not os.getenv("DBG_NOCOLOR") then
+   COLOR_GRAY = string.char(27) .. "[90m"
+   COLOR_RED = string.char(27) .. "[91m"
+   COLOR_BLUE = string.char(27) .. "[94m"
+   COLOR_YELLOW = string.char(27) .. "[33m"
+   COLOR_RESET = string.char(27) .. "[0m"
+   GREEN_CARET = string.char(27) .. "[92m => "..COLOR_RESET
+end
+
+dbg_writeln(COLOR_YELLOW.."debugger.lua: "..COLOR_RESET.."Loaded for ".._VERSION.." (Lite-XL)")
+
+command.add(nil, {
+   ["debugger:break"] = function()
+      dbg()
+   end,
+})