--------------------------------------------------------------------------------

--- Visualization of non-recursive tables.

-- @module lua-nucleo.tstr

-- This file is a part of lua-nucleo library

-- @copyright lua-nucleo authors (see file `COPYRIGHT` for the license)

--------------------------------------------------------------------------------

local pairs, ipairs, type, tostring = pairs, ipairs, type, tostring

local table_concat = table.concat

local string_match, string_format = string.match, string.format

--local lua51_keywords = import 'lua-nucleo/language.lua' { 'lua51_keywords' }

--local serialize_number = import 'lua-nucleo/string.lua' { 'serialize_number' }

local lua51_keywords = get('#155').lua51_keywords

local serialize_number = get('#156').serialize_number

local tstr, tstr_cat

do

  local function impl(t, cat, visited)

    local t_type = type(t)

    if t_type == "table" then

      if not visited[t] then

        visited[t] = true

        cat("{")

        -- Serialize numeric indices

        local next_i = 0

        for i, v in ipairs(t) do -- TODO: Lua 5.2 warning. Rewrite.

          if i > 1 then -- TODO: Move condition out of the loop

            cat(",")

          end

          impl(v, cat, visited)

          next_i = i

        end

        next_i = next_i + 1

        -- Serialize hash part

        -- Skipping comma only at first element if there is no numeric part.

        local need_comma = (next_i > 1)

        for k, v in pairs(t) do

          local k_type = type(k)

          if k_type == "string" then

            if need_comma then

              cat(",")

            end

            need_comma = true

            -- TODO: Need "%q" analogue, which would put quotes

            -- only if string does not match regexp below

            if not lua51_keywords[k] and string_match(k, "^[%a_][%a%d_]*$") then

              cat(k) cat("=")

            else

              cat(string_format("[%q]=", k))

            end

            impl(v, cat, visited)

          else

            if

              k_type ~= "number" or -- non-string non-number

              k >= next_i or k < 1 or -- integer key in hash part of the table

              k % 1 ~= 0 -- non-integer key

            then

              if need_comma then

                cat(",")

              end

              need_comma = true

              cat("[")

              impl(k, cat, visited)

              cat("]=")

              impl(v, cat, visited)

            end

          end

        end

        cat("}")

        visited[t] = nil

      else

        -- Note this loses information on recursive tables

        cat('"table (recursive)"')

      end

    elseif t_type == "number" then

      cat(serialize_number(t))

    elseif t_type == "boolean" then

      cat(tostring(t))

    elseif t == nil then

      cat("nil")

    else

      -- Note this converts non-serializable types to strings

      cat(string_format("%q", tostring(t)))

    end

  end

  -- This function is optimized for logging.

  -- Unless you are serializing "simple" tables,

  -- do not use this function for serialization.

  -- This function intentionally loses information on nested recursive tables

  -- and on non-serializable types like functions, threads and userdata.

  tstr_cat = function(cat, t)

    impl(t, cat, {})

  end

  tstr = function(t)

    local buf = {}

    local cat = function(v) buf[#buf + 1] = v end

    impl(t, cat, {})

    return table_concat(buf)

  end

end

return

{

  tstr = tstr;

  tstr_cat = tstr_cat;

}