[NTG-context] lua tables - how do you cope?

Lukas Prochazka lpr at pontex.cz
Sat Jul 30 23:46:07 CEST 2016


Hello Thomas,

here is my "dump()" I've been using for several years:

----
function dump(arg, opts) -- .seen, .pfx
  if type(opts) == "string" then print(opts); opts = nil
  elseif opts == true then print("-- (dump)"); opts = nil
  end

  local pfx = opts and opts.pfx
  local seen = opts and opts.seen or {}

  if type(arg) == "table" then
    if pfx then pfx = pfx .. "]["
    else
      pfx = "["
      --seen = {}
    end

    seen[arg] = tostring(arg) --true

    local keys = {}

    do
      -- Sort keys, if all are strings

      local strs_only = true

      for k in pairs(arg) do
        if strs_only and type(k) ~= "string" then strs_only = false end

        keys[#keys + 1] = k
      end

      if strs_only then table.sort(keys) end
    end

    for _, key in ipairs(keys) do
      local val = arg[key]

      io.write(pfx .. tostring(key) .. "] = " .. tostring(val) .. "\t(" .. type(val) .. ")")

      if type(val) == "table" then
        if seen[val] then print(" (seen)")
        else
          print()

          dump(val, {pfx = pfx .. tostring(key), seen = seen}) --pfx .. tostring(key), seen)
        end
      else
        print()
      end
    end
  else
    print(arg)
  end
end
----

Try:

----
a = {c = 1, b = 2}; a.a = a

dump(a)
dump(a, "This is 'a'.")
----

Improvements or parametrization of visualizing style would be possible, of course... 

Best regards,

Lukas


----- Original Message -----
From: Schmitz Thomas A. [mailto:thomas.schmitz at uni-bonn.de]
To: mailing list for ConTeXt users [mailto:ntg-context at ntg.nl]
Sent: Sat, 30 Jul 2016 23:01:29 +0100
Subject: Re: [NTG-context] lua tables - how do you cope?


> Thank you, but this is not what I’m looking for. I know how to sort a table, and I know the Lua table tutorial (the Lua wiki is, IMHO, really terrible and disorganized). I have to construct deeply nested tables and sometimes lose track of what is at what level of my table, so I was wondering if there was an easy way of visualizing a nested table. On the web, you can find a number of (mostly abandoned) projects; the one at http://siffiejoe.github.io/lua-microscope/ says: "Many Lua programmers have written their own pretty-printer or data dumper and some even use it for (de-)serializing Lua data structures.” So I was wondering if any of the Lua users here on the list has something they want to share.

Thomas


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