debug.traceback() in Lua?

[Eduardo Ochs <eduardoochs@...>]

Hi list,

where can I find a version in Lua of debug.traceback()?
I know that there is one in Fennel... its original code -
in Fennel - is here,

https://git.sr.ht/~technomancy/fennel/tree/main/item/src/fennel/compiler.fnl#L827-873

and we can obtain its translation to Lua by running this:

  rm -Rfv /tmp/fennel/
  cd      /tmp/
  git clone https://git.sr.ht/~technomancy/fennel
  cd      /tmp/fennel/
  make -f Makefile LUA_VERSION=5.2
  awk '2902<=NR && NR<=2963' bootstrap/fennel.lua  | tee tb.lua

After running the code above the file /tmp/fennel/tb.lua
will contain this:

  local function traceback_frame(info)
    if ((info.what == "C") and info.name) then
      return string.format("  [C]: in function '%s'", info.name)
    elseif (info.what == "C") then
      return "  [C]: in ?"
    else
      local remap = sourcemap[info.source]
      if (remap and remap[info.currentline]) then
        if remap[info.currentline][1] then
          info.short_src = sourcemap[("@" ..
remap[info.currentline][1])].short_src
        else
          info.short_src = remap.short_src
        end
        info.currentline = (remap[info.currentline][2] or -1)
      else
      end
      if (info.what == "Lua") then
        local function _325_()
          if info.name then
            return ("'" .. info.name .. "'")
          else
            return "?"
          end
        end
        return string.format("  %s:%d: in function %s",
info.short_src, info.currentline, _325_())
      elseif (info.short_src == "(tail call)") then
        return "  (tail call)"
      else
        return string.format("  %s:%d: in main chunk", info.short_src,
info.currentline)
      end
    end
  end
  local function traceback(msg, start)
    local msg0 = tostring((msg or ""))
    if ((msg0:find("^Compile error") or msg0:find("^Parse error")) and
not utils["debug-on?"]("trace")) then
      return msg0
    else
      local lines = {}
      if (msg0:find(":%d+: Compile error") or msg0:find(":%d+: Parse
error")) then
        table.insert(lines, msg0)
      else
        local newmsg = msg0:gsub("^[^:]*:%d+:%s+", "runtime error: ")
        table.insert(lines, newmsg)
      end
      table.insert(lines, "stack traceback:")
      local done_3f, level = false, (start or 2)
      while not done_3f do
        do
          local _329_ = debug.getinfo(level, "Sln")
          if (_329_ == nil) then
            done_3f = true
          elseif (nil ~= _329_) then
            local info = _329_
            table.insert(lines, traceback_frame(info))
          else
          end
        end
        level = (level + 1)
      end
      return table.concat(lines, "\n")
    end
  end

This seems to be loosely based on the function db_errorfb in the file
src/ldblib.c of the Lua source, but with several changes... I can try
to modify that code to make it more similar to db_errorfb, but I am
not a good programmer, and that would probably take many hours - and I
think that having other "debug.tracebacks()"s in Lua to compare would
save me a lot of time...

  Thanks in advance!
    Eduardo Ochs
    http://angg.twu.net/#eev
    http://angg.twu.net/dednat6.html
    http://angg.twu.net/dednat6/tug-slides.pdf