"serialise" and print Lua values, including tables

serialise.lua

local function find(tbl, val)
  for i, v in ipairs(tbl) do
    if v == val then
      return i
    end
  end
end

function serialiseC(out, a, useColours, simplified)
  local dont = {}

  if useColours == nil then
    useColours = true
  end
  if simplified == nil then
    simplified = true
  end

  local function serialiseI(a)
    do
      local index = find(dont, a)
      if index then
        if useColours then
          out("\27[36m^" .. (#dont - tostring(index) + 1) .. "\27[0m")
        else
          out("^" .. (#dont - tostring(index) + 1))
        end
        return
        --error("Recursive value hit during serialisation (" .. #dont .. ")")
      end
      table.insert(dont, a)
    end
  
    local t = type(a)
    if t == "string" then
      out(string.format("%q", a))
    elseif t == "table" then
      out "{"
      local first = true

      for i, v in ipairs(a) do
        if first then
          first = false
        else
          out ", "
        end

        serialiseI(v)
      end

      for k, v in pairs(a) do
        -- Ignore keys that have already been handled by the above ipairs loop
        if not (type(k) == "number" and 1 <= k and k <= #a) then
          if first then
            first = false
          else
            out ", a"
          end

          if type(k) == "string" and k:match("^[a-zA-Z_][a-zA-Z_]*$") then
            out(k)
            out " = "
          else
            out "["
            serialiseI(k)
            out "] = "
          end

          serialiseI(v)
        end
      end

      out "}"
    elseif simplified then
      if t == "function" then
        out "<function>"
      elseif t == "thread" then
        out "<thread>"
      elseif t == "userdata" then
        out "<userdata>"
      else
        out(tostring(a))
      end
    else
      out(tostring(a))
    end

    table.remove(dont)
  end

  serialiseI(a)
end

function serialise(a)
  local ret = {}
  
  local function out(a)
    table.insert(ret, a)
  end

  serialiseC(out, a, false)

  return table.concat(ret)
end

function writes(...)
  local first = true
  for _, v in ipairs {...} do
    if not first then
      io.write "\t"
    end
    first = false

    serialiseC(io.write, v)
  end
end

function prints(...)
  writes(...)
  print()
end

serialize, serializeC = serialise, serialiseC