initial commit

src/import/LuaWriter.lua

@@ -0,0 +1,99 @@
+local LuaWriter = {}
+
+local KEYWORDS = {
+  ["and"] = true, ["break"] = true, ["do"] = true, ["else"] = true,
+  ["elseif"] = true, ["end"] = true, ["false"] = true, ["for"] = true,
+  ["function"] = true, ["goto"] = true, ["if"] = true, ["in"] = true,
+  ["local"] = true, ["nil"] = true, ["not"] = true, ["or"] = true,
+  ["repeat"] = true, ["return"] = true, ["then"] = true, ["true"] = true,
+  ["until"] = true, ["while"] = true,
+}
+
+local function quote(value)
+  local escaped = value:gsub('[%z\1-\31\\"]', function(character)
+    if character == "\\" then return "\\\\" end
+    if character == '"' then return '\\"' end
+    if character == "\n" then return "\\n" end
+    if character == "\r" then return "\\r" end
+    if character == "\t" then return "\\t" end
+    return ("\\%03d"):format(character:byte())
+  end)
+  return '"' .. escaped .. '"'
+end
+
+local function keyText(key)
+  if type(key) == "string"
+      and key:match("^[A-Za-z_][A-Za-z0-9_]*$")
+      and not KEYWORDS[key] then
+    return key
+  end
+  return "[" .. (type(key) == "string" and quote(key) or tostring(key)) .. "]"
+end
+
+local function isArray(value)
+  local count, maximum = 0, 0
+  for key in pairs(value) do
+    if type(key) ~= "number" or key < 1 or key % 1 ~= 0 then
+      return false, 0
+    end
+    count = count + 1
+    maximum = math.max(maximum, key)
+  end
+  return count == maximum, maximum
+end
+
+local function sortedKeys(value)
+  local keys = {}
+  for key in pairs(value) do keys[#keys + 1] = key end
+  table.sort(keys, function(a, b)
+    if type(a) == type(b) then return a < b end
+    return type(a) == "number"
+  end)
+  return keys
+end
+
+local function encode(value, indent, seen)
+  local kind = type(value)
+  if value == nil then return "nil" end
+  if kind == "boolean" or kind == "number" then return tostring(value) end
+  if kind == "string" then return quote(value) end
+  if kind ~= "table" then
+    error("cannot serialize " .. kind)
+  end
+  if seen[value] then error("cannot serialize a cyclic table") end
+  seen[value] = true
+
+  local pad = string.rep("  ", indent)
+  local childPad = string.rep("  ", indent + 1)
+  local out = {}
+  local array, length = isArray(value)
+  if array then
+    for index = 1, length do
+      out[#out + 1] = childPad .. encode(value[index], indent + 1, seen) .. ","
+    end
+  else
+    for _, key in ipairs(sortedKeys(value)) do
+      out[#out + 1] = childPad .. keyText(key) .. " = "
+        .. encode(value[key], indent + 1, seen) .. ","
+    end
+  end
+  seen[value] = nil
+  if #out == 0 then return "{}" end
+  return "{\n" .. table.concat(out, "\n") .. "\n" .. pad .. "}"
+end
+
+function LuaWriter.encode(value)
+  return "return " .. encode(value, 0, {}) .. "\n"
+end
+
+function LuaWriter.write(path, value)
+  local parent = path:match("^(.*)/[^/]+$")
+  if parent then
+    local ok, err = love.filesystem.createDirectory(parent)
+    if not ok then error("could not create " .. parent .. ": " .. tostring(err)) end
+  end
+  local ok, err = love.filesystem.write(path, LuaWriter.encode(value))
+  if not ok then error("could not write " .. path .. ": " .. tostring(err)) end
+end
+
+return LuaWriter