Function to improve on 'print(table)'...

[Duck <duck@...>]

In another thread, someone asked for a feature so that instead of:

 > print(table)
 table: 0x806e468

you might be able to do something like this:

 > dumptable(table)
 { [1]
    setn()
    insert()
    getn()
    foreachi()
    maxn()
    foreach()
    concat()
    sort()
    remove()
 }

or like this:

 > t = {}
 > t[1] = "banana"
 > t[2] = { fruit = "mango", qty = 45 }
 > dumptable(t)
 { [1]
    1 "banana"
    2 { [2]
       qty = 45
       fruit "mango"
    }
 }
 > t[3] = t
 > dumptable(t)
 { [1]
    1 "banana"
    2 { [2]
       qty = 45
       fruit "mango"
    }
    3 {}-->[1]
 }

for which I use something like this (the numbers in [square brackets] 
aren't table indexes, but just cross references to tables which have 
already been seen -- try dumptable(_G) to see what I mean). It's meant to 
be a sort of legible serialisation for troubleshooting your data.

---cut here---

function dumptable(tab)
   local tableseen   = {}
   local tableseqno  = 1
   local tablestrmax = 45
   local tableindent = 3

   local function tabledump(tab,n)
      if tab == nil then io.write("nil\n"); return end
      if tableseen[tab] ~= nil then return end
      tableseen[tab] = tableseqno
      io.write("{ ["..tableseqno.."]\n")
      tableseqno = tableseqno + 1
      for k, v in pairs(tab) do
	 local id = tostring(k)
	 local val = tostring(v)
	 io.write(string.format("%s%s",string.rep(" ",n),id))
	 if type(v) == "function" then
	    io.write("()\n")
	 elseif type(v) == "string" then
	    io.write(' "'..val:sub(1,tablestrmax))
	    if (val:len() > tablestrmax) then io.write("...") end
	    io.write('"\n')
	 elseif type(v) == "table" then
	    io.write(" ")
	    if tableseen[v] ~= nil then
	       io.write("{}-->["..tableseen[v].."]\n")
	    else
	       tabledump(v,n+tableindent)
	    end
	 elseif type(v) == "number" then
	    io.write(" = "..val.."\n")
	 else
	    io.write(" "..val.."\n")
	 end
      end
      io.write(string.rep(" ",n-tableindent).."}\n")
   end

   tabledump(tab,tableindent)
end

---cut here---