a recursive Lua table inspector

local insp={}

assert( type(insp)=="table" )

function InspectValue(value,history,indent,inside)
 res=""
 for vkey,vvalue in pairs(value) do
  local vvtype=type(vvalue)
  res=res..(string.rep(" ",indent)..tostring(vkey).." ["..tostring(vvalue).."]").."\n"
  if not history[vvalue] then
   if vvtype=="table" then
    res=res..__Inspect(vvalue,indent+2,history,inside)
   elseif vvtype=="function" then
    res=res..InspectFunction(vvalue,history,indent+2,inside)
   end --if vvtype
  end --if not hist
  history[vvalue]=true
 end --for vkey
 return res
end

function InspectFunction(value,history,indent,inside)
 res=""
 local ftab=debug.getinfo(value,"S")
 if ftab~=nil then
  res=res..(string.rep(" ",indent).."Function info:").."\n"
  res=res..__Inspect(ftab,indent+1,history,false,inside)
 end
 return res
end

--reverse lookup of values that are defined in an environment
function __InsideG()
 local ins={}
  for key,value in pairs(_G) do
   ins[value]=true
  end
 return ins
end

function ProperLevel(T,inside,value)
 if T~=_G and inside[value] then return false end
 return true
end

local InBlackList = {
 InspectValue=true,
 InspectFunction=true,
 __InsideG=true,
 ProperLevel=true,
 __Inspect=true,
 Inspect=true,
 InBlackList=true,
 source=true
}

function __Inspect(T,ind,hist,meta,InsideG)
 local res=""
 local inside=InsideG or __InsideG()
 if T==nil then return "nil" end
 if (type(T)~="table") then return res end

 local indent=ind or 0
 local history=hist or {}

 if (type(history)~="table") then history={} end

 history[T]=true
 for key,value in pairs(T) do
  if not InBlackList[key] then
   res=res..(string.rep(" ",indent)..tostring(key).." ["..tostring(value).."]").."\n"
   if value and not history[value] and ProperLevel(T,inside,value) then
    history[value]=true
    if type(value)=="table" then
     res=res..InspectValue(value,history,indent+1,inside)
    elseif debug and type(value)=="function" then
     res=res..InspectFunction(value,history,indent+1,inside)
    end --if type(value)
    local mt=nil
    if meta then mt=getmetatable(value) end
    if mt then
     if type(mt)=="table" then
      res=res..(string.rep(" ",indent+1).."Metatable:").."\n"
      res=res..__Inspect(mt,indent+2,history,meta,inside)
     else
      res=res..tostring(mt).."\n"
     end
    end
   end
  end
 end
 return res
end

-- inspects the table recursively (Inspect(_G) inspects the environment)
function insp.Inspect(T)
 return __Inspect(T,nil,nil,true,nil)
end

--return insp

local Inspector=insp --require("insp")
print(Inspector.Inspect(_G))