Module:JsonOrdered

La documentation pour ce module peut être créée à Module:JsonOrdered/doc

-- table ordered
local ordered_table = {}

local _values = {}
local _keys = {}

function ordered_table.insert(t, k, v)
  if v == nil then
    ordered_table.remove(t, k)
  else -- update/store value
    if t[_values][k] == nil then -- new key 
      t[_keys][#t[_keys] + 1] = k
    end
    t[_values][k] = v 
  end
end

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

function ordered_table.remove(t, k)
  local tv = t[_values]
  local v = tv[k]
  if v ~= nil then
    local tk = t[_keys]
    table.remove(tk, assert(find(tk, k)))
    tv[k] = nil
  end 
  return v
end

function ordered_table.pairs(t)
  local i = 0
  return function()
    i = i + 1
    local key = t[_keys][i]
    if key ~= nil then
      return key, t[_values][key]
    end
  end
end

-- set metamethods for ordered_table "class"
ordered_table.__newindex=ordered_table.insert -- called for updates too since we store the value in `_values` instead. 
ordered_table.__len=function(t) return #t[_keys] end
ordered_table.__pairs=ordered_table.pairs
ordered_table.__index=function(t, k) return t[_values][k] end -- function so we can share between tables 

function ordered_table:new(init)
  init = init or {}
  local key_table = {}
  local value_table = {}
  local t = {[_keys]=key_table, [_values]=value_table}
  local n = #init
  if n % 2 ~= 0 then
    error("key: "..tostring(init[#init]).." is missing value", 2)
  end
  for i=1,n/2 do
    local k = init[i * 2 - 1]
    local v = init[i * 2]
    if value_table[k] ~= nil then
      error("duplicated key:"..tostring(k), 2)
    end
    key_table[#key_table + 1]  = k
    value_table[k] = v
  end
  return setmetatable(t, self)
end

ordered_table = setmetatable(ordered_table, {__call=ordered_table.new})

-- json decoder that keep table order
local json = { _version = "0.1.2" }
local parse

local function create_set(...)
  local res = {}
  for i = 1, select("#", ...) do
    res[ select(i, ...) ] = true
  end
  return res
end

local space_chars   = create_set(" ", "\t", "\r", "\n")
local delim_chars   = create_set(" ", "\t", "\r", "\n", "]", "}", ",")
local escape_chars  = create_set("\\", "/", '"', "b", "f", "n", "r", "t", "u")
local literals      = create_set("true", "false", "null")

local literal_map = {
  [ "true"  ] = true,
  [ "false" ] = false,
  [ "null"  ] = nil,
}

local function next_char(str, idx, set, negate)
  for i = idx, #str do
    if set[str:sub(i, i)] ~= negate then
      return i
    end
  end
  return #str + 1
end

local function decode_error(str, idx, msg)
  local line_count = 1
  local col_count = 1
  for i = 1, idx - 1 do
    col_count = col_count + 1
    if str:sub(i, i) == "\n" then
      line_count = line_count + 1
      col_count = 1
    end
  end
  error( string.format("%s at line %d col %d", msg, line_count, col_count) )
end

local function codepoint_to_utf8(n)
  -- http://scripts.sil.org/cms/scripts/page.php?site_id=nrsi&id=iws-appendixa
  local f = math.floor
  if n <= 0x7f then
    return string.char(n)
  elseif n <= 0x7ff then
    return string.char(f(n / 64) + 192, n % 64 + 128)
  elseif n <= 0xffff then
    return string.char(f(n / 4096) + 224, f(n % 4096 / 64) + 128, n % 64 + 128)
  elseif n <= 0x10ffff then
    return string.char(f(n / 262144) + 240, f(n % 262144 / 4096) + 128,
                       f(n % 4096 / 64) + 128, n % 64 + 128)
  end
  error( string.format("invalid unicode codepoint '%x'", n) )
end

local function parse_unicode_escape(s)
  local n1 = tonumber( s:sub(1, 4),  16 )
  local n2 = tonumber( s:sub(7, 10), 16 )
   -- Surrogate pair?
  if n2 then
    return codepoint_to_utf8((n1 - 0xd800) * 0x400 + (n2 - 0xdc00) + 0x10000)
  else
    return codepoint_to_utf8(n1)
  end
end

local function parse_string(str, i)
  local res = ""
  local j = i + 1
  local k = j

  while j <= #str do
    local x = str:byte(j)

    if x < 32 then
      decode_error(str, j, "control character in string")

    elseif x == 92 then -- `\`: Escape
      res = res .. str:sub(k, j - 1)
      j = j + 1
      local c = str:sub(j, j)
      if c == "u" then
        local hex = str:match("^[dD][89aAbB]%x%x\\u%x%x%x%x", j + 1)
                 or str:match("^%x%x%x%x", j + 1)
                 or decode_error(str, j - 1, "invalid unicode escape in string")
        res = res .. parse_unicode_escape(hex)
        j = j + #hex
      else
        if not escape_chars[c] then
          decode_error(str, j - 1, "invalid escape char '" .. c .. "' in string")
        end
        res = res .. escape_char_map_inv[c]
      end
      k = j + 1

    elseif x == 34 then -- `"`: End of string
      res = res .. str:sub(k, j - 1)
      return res, j + 1
    end

    j = j + 1
  end

  decode_error(str, i, "expected closing quote for string")
end

local function parse_number(str, i)
  local x = next_char(str, i, delim_chars)
  local s = str:sub(i, x - 1)
  local n = tonumber(s)
  if not n then
    decode_error(str, i, "invalid number '" .. s .. "'")
  end
  return n, x
end

local function parse_literal(str, i)
  local x = next_char(str, i, delim_chars)
  local word = str:sub(i, x - 1)
  if not literals[word] then
    decode_error(str, i, "invalid literal '" .. word .. "'")
  end
  return literal_map[word], x
end

local function parse_array(str, i)
  local res = {}
  local n = 1
  i = i + 1
  while 1 do
    local x
    i = next_char(str, i, space_chars, true)
    -- Empty / end of array?
    if str:sub(i, i) == "]" then
      i = i + 1
      break
    end
    -- Read token
    x, i = parse(str, i)
    res[n] = x
    n = n + 1
    -- Next token
    i = next_char(str, i, space_chars, true)
    local chr = str:sub(i, i)
    i = i + 1
    if chr == "]" then break end
    if chr ~= "," then decode_error(str, i, "expected ']' or ','") end
  end
  return res, i
end

local function parse_object(str, i)
  local res = ordered_table{}
  i = i + 1
  while 1 do
    local key, val
    i = next_char(str, i, space_chars, true)
    -- Empty / end of object?
    if str:sub(i, i) == "}" then
      i = i + 1
      break
    end
    -- Read key
    if str:sub(i, i) ~= '"' then
      decode_error(str, i, "expected string for key")
    end
    key, i = parse(str, i)
    -- Read ':' delimiter
    i = next_char(str, i, space_chars, true)
    if str:sub(i, i) ~= ":" then
      decode_error(str, i, "expected ':' after key")
    end
    i = next_char(str, i + 1, space_chars, true)
    -- Read value
    val, i = parse(str, i)
    -- Set
    res[key] = val
    -- Next token
    i = next_char(str, i, space_chars, true)
    local chr = str:sub(i, i)
    i = i + 1
    if chr == "}" then break end
    if chr ~= "," then decode_error(str, i, "expected '}' or ','") end
  end
  return res, i
end

local char_func_map = {
    [ '"' ] = parse_string,
    [ "0" ] = parse_number,
    [ "1" ] = parse_number,
    [ "2" ] = parse_number,
    [ "3" ] = parse_number,
    [ "4" ] = parse_number,
    [ "5" ] = parse_number,
    [ "6" ] = parse_number,
    [ "7" ] = parse_number,
    [ "8" ] = parse_number,
    [ "9" ] = parse_number,
    [ "-" ] = parse_number,
    [ "t" ] = parse_literal,
    [ "f" ] = parse_literal,
    [ "n" ] = parse_literal,
    [ "[" ] = parse_array,
    [ "{" ] = parse_object,
  }
  
parse = function(str, idx)
    local chr = str:sub(idx, idx)
    local f = char_func_map[chr]
    if f then
      return f(str, idx)
    end
    decode_error(str, idx, "unexpected character '" .. chr .. "'")
  end
  
function json.decode(str)
    if type(str) ~= "string" then
      error("expected argument of type string, got " .. type(str))
    end
    local res, idx = parse(str, next_char(str, 1, space_chars, true))
    idx = next_char(str, idx, space_chars, true)
    if idx <= #str then
      decode_error(str, idx, "trailing garbage")
    end
    return res
  end

  return json