Dumping data

I am so used to using Dumper in Perl, NSLog in Objective C and print_r in php to name a few functions to dump data, or serialize data also.

I can't find any simple way of just dumping data from a variable. What I find by using google are huge functions. Is there no built in function into corona or lua ?

This is so trivial for example when you are fetching json or xml data from the web, or whatever. very important.

This function would also have to dump tables.

Have you seen this?
http://lua-users.org/wiki/TableSerialization

I use Penlight's pretty-print module. It has the added benefit that you can save the output to a file and load it back to recreate the table that you output.

You can find the module here:

https://github.com/stevedonovan/Penlight/blob/master/lua/pl/pretty.lua

Penlight's module has some dependencies on some other modules, so if you want something smaller you can use the following code from stdlib's base.lua:

-- @func tostring: Extend tostring to work better on tables
--   @param x: object to convert to string
-- @returns
--   @param s: string representation
_G._tostring = tostring -- make original tostring available
local _tostring = tostring
function _G.tostring (x)
  return render (x,
                 function () return "{" end,
                 function () return "}" end,
                 _tostring,
                 function (t, _, _, i, v)
                   return i .. "=" .. v
                 end,
                 function (_, i, _, j)
                   if i and j then
                     return ","
                   end
                   return ""
                 end)
end
 
-- @func prettytostring: pretty-print a table
--   @t: table to print
--   @indent: indent between levels ["\t"]
--   @spacing: space before every line
-- @returns
--   @s: pretty-printed string
function _G.prettytostring (t, indent, spacing)
  indent = indent or "\t"
  spacing = spacing or ""
  return render (t,
                 function ()
                   local s = spacing .. "{"
                   spacing = spacing .. indent
                   return s
                 end,
                 function ()
                   spacing = string.gsub (spacing, indent .. "$", "")
                   return spacing .. "}"
                 end,
                 function (x)
                   if type (x) == "string" then
                     return string.format ("%q", x)
                   else
                     return tostring (x)
                   end
                 end,
                 function (x, i, v, is, vs)
                   local s = spacing .. "["
                   if type (i) == "table" then
                     s = s .. "\n"
                   end
                   s = s .. is
                   if type (i) == "table" then
                     s = s .. "\n"
                   end
                   s = s .. "] ="
                   if type (v) == "table" then
                     s = s .. "\n"
                   else
                     s = s .. " "
                   end
                   s = s .. vs
                   return s
                 end,
                 function (_, i)
                   local s = "\n"
                   if i then
                     s = "," .. s
                   end
                   return s
                 end)
end

views:1572 update：2011/10/5 21:23:48


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