Module:Inspect

local inspect ={ _VERSION = 'inspect.lua 3.1.0', _URL    = 'http://github.com/kikito/inspect.lua', _DESCRIPTION = 'human-readable representations of tables', _LICENSE = [[   MIT LICENSE

Copyright (c) 2013 Enrique García Cota

Permission is hereby granted, free of charge, to any person obtaining a   copy of this software and associated documentation files (the    "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to   permit persons to whom the Software is furnished to do so, subject to    the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. ]] }

local tostring = tostring

inspect.KEY      = setmetatable({}, {__tostring = function return 'inspect.KEY' end}) inspect.METATABLE = setmetatable({}, {__tostring = function return 'inspect.METATABLE' end})

-- Apostrophizes the string if it has quotes, but not aphostrophes -- Otherwise, it returns a regular quoted string local function smartQuote(str) if str:match('"') and not str:match("'") then   return "'" .. str .. "'"  end  return '"' .. str:gsub('"', '\\"') .. '"' end

-- \a => '\\a', \0 => '\\0', 31 => '\31' local shortControlCharEscapes = { ["\a"] = "\\a", ["\b"] = "\\b", ["\f"] = "\\f", ["\n"] = "\\n", ["\r"] = "\\r", ["\t"] = "\\t", ["\v"] = "\\v" } local longControlCharEscapes = {} -- \a => nil, \0 => \000, 31 => \031 for i=0, 31 do local ch = string.char(i) if not shortControlCharEscapes[ch] then shortControlCharEscapes[ch] = "\\"..i   longControlCharEscapes[ch]  = string.format("\\%03d", i)  end end

local function escape(str) return (str:gsub("\\", "\\\\")            :gsub("(%c)%f[0-9]", longControlCharEscapes)             :gsub("%c", shortControlCharEscapes)) end

local function isIdentifier(str) return type(str) == 'string' and str:match( "^[_%a][_%a%d]*$" ) end

local function isSequenceKey(k, sequenceLength) return type(k) == 'number' and 1 <= k    and k <= sequenceLength and math.floor(k) == k end

local defaultTypeOrders = { ['number']  = 1, ['boolean']  = 2, ['string'] = 3, ['table'] = 4, ['function'] = 5, ['userdata'] = 6, ['thread'] = 7 }

local function sortKeys(a, b) local ta, tb = type(a), type(b)

-- strings and numbers are sorted numerically/alphabetically if ta == tb and (ta == 'string' or ta == 'number') then return a < b end

local dta, dtb = defaultTypeOrders[ta], defaultTypeOrders[tb] -- Two default types are compared according to the defaultTypeOrders table if dta and dtb then return defaultTypeOrders[ta] < defaultTypeOrders[tb] elseif dta    then return true  -- default types before custom ones elseif dtb    then return false -- custom types after default ones end

-- custom types are sorted out alphabetically return ta < tb end

-- For implementation reasons, the behavior of rawlen & # is "undefined" when -- tables aren't pure sequences. So we implement our own # operator. local function getSequenceLength(t) local len = 1 local v = rawget(t,len) while v ~= nil do   len = len + 1 v = rawget(t,len) end return len - 1 end

local function getNonSequentialKeys(t) local keys = {} local sequenceLength = getSequenceLength(t) for k,_ in pairs(t) do   if not isSequenceKey(k, sequenceLength) then table.insert(keys, k) end end table.sort(keys, sortKeys) return keys, sequenceLength end

local function getToStringResultSafely(t, mt) local __tostring = type(mt) == 'table' and rawget(mt, '__tostring') local str, ok if type(__tostring) == 'function' then ok, str = pcall(__tostring, t)   str = ok and str or 'error: ' .. tostring(str) end if type(str) == 'string' and #str > 0 then return str end end

local function countTableAppearances(t, tableAppearances) tableAppearances = tableAppearances or {}

if type(t) == 'table' then if not tableAppearances[t] then tableAppearances[t] = 1 for k,v in pairs(t) do       countTableAppearances(k, tableAppearances) countTableAppearances(v, tableAppearances) end countTableAppearances(getmetatable(t), tableAppearances) else tableAppearances[t] = tableAppearances[t] + 1 end end

return tableAppearances end

local copySequence = function(s) local copy, len = {}, #s for i=1, len do copy[i] = s[i] end return copy, len end

local function makePath(path, ...) local keys = {...} local newPath, len = copySequence(path) for i=1, #keys do   newPath[len + i] = keys[i] end return newPath end

local function processRecursive(process, item, path, visited)

if item == nil then return nil end if visited[item] then return visited[item] end

local processed = process(item, path) if type(processed) == 'table' then local processedCopy = {} visited[item] = processedCopy local processedKey

for k,v in pairs(processed) do       processedKey = processRecursive(process, k, makePath(path, k, inspect.KEY), visited) if processedKey ~= nil then processedCopy[processedKey] = processRecursive(process, v, makePath(path, processedKey), visited) end end

local mt = processRecursive(process, getmetatable(processed), makePath(path, inspect.METATABLE), visited) setmetatable(processedCopy, mt) processed = processedCopy end return processed end

---

local Inspector = {} local Inspector_mt = {__index = Inspector}

function Inspector:puts(...) local args  = {...} local buffer = self.buffer local len   = #buffer for i=1, #args do   len = len + 1 buffer[len] = args[i] end end

function Inspector:down(f) self.level = self.level + 1 f self.level = self.level - 1 end

function Inspector:tabify self:puts(self.newline, string.rep(self.indent, self.level)) end

function Inspector:alreadyVisited(v) return self.ids[v] ~= nil end

function Inspector:getId(v) local id = self.ids[v] if not id then local tv = type(v) id             = (self.maxIds[tv] or 0) + 1 self.maxIds[tv] = id   self.ids[v]     = id  end return tostring(id) end

function Inspector:putKey(k) if isIdentifier(k) then return self:puts(k) end self:puts("[") self:putValue(k) self:puts("]") end

function Inspector:putTable(t) if t == inspect.KEY or t == inspect.METATABLE then self:puts(tostring(t)) elseif self:alreadyVisited(t) then self:puts('') elseif self.level >= self.depth then self:puts('{...}') else if self.tableAppearances[t] > 1 then self:puts('<', self:getId(t), '>') end

local nonSequentialKeys, sequenceLength = getNonSequentialKeys(t) local mt               = getmetatable(t) local toStringResult   = getToStringResultSafely(t, mt)

self:puts('{') self:down(function     if toStringResult then        self:puts(' -- ', escape(toStringResult))        if sequenceLength >= 1 then self:tabify end      end

local count = 0 for i=1, sequenceLength do       if count > 0 then self:puts(',') end self:puts(' ') self:putValue(t[i]) count = count + 1 end

for _,k in ipairs(nonSequentialKeys) do       if count > 0 then self:puts(',') end self:tabify self:putKey(k) self:puts(' = ') self:putValue(t[k]) count = count + 1 end

if mt then if count > 0 then self:puts(',') end self:tabify self:puts(' = ') self:putValue(mt) end end)

if #nonSequentialKeys > 0 or mt then -- result is multi-lined. Justify closing } self:tabify elseif sequenceLength > 0 then -- array tables have one extra space before closing } self:puts(' ') end

self:puts('}') end end

function Inspector:putValue(v) local tv = type(v)

if tv == 'string' then self:puts(smartQuote(escape(v))) elseif tv == 'number' or tv == 'boolean' or tv == 'nil' then self:puts(tostring(v)) elseif tv == 'table' then self:putTable(v) else self:puts('<',tv,' ',self:getId(v),'>') end end

---

function inspect.inspect(root, options) options      = options or {}

local depth  = options.depth   or math.huge local newline = options.newline or '\n' local indent = options.indent  or '  ' local process = options.process

if process then root = processRecursive(process, root, {}, {}) end

local inspector = setmetatable({   depth            = depth,    level            = 0,    buffer           = {},    ids              = {},    maxIds           = {},    newline          = newline,    indent           = indent,    tableAppearances = countTableAppearances(root)  }, Inspector_mt)

inspector:putValue(root)

return table.concat(inspector.buffer) end

setmetatable(inspect, { __call = function(_, ...) return inspect.inspect(...) end })

return inspect