local m_str_utils = require("Module:string utilities")
local m_table = require("Module:table")
local codepoint = m_str_utils.codepoint
local gsub = m_str_utils.gsub
local export = {}
-- Given a finite real number x, returns a string containing its JSON
-- representation, with enough precision that it *should* round-trip correctly
-- (depending on the well-behavedness of the system on the other end).
function export.json_fromNumber(x)
if type(x) ~= "number" then
error('Not of type "number": ' .. x .. " (" .. type(x) .. ")")
end
if x ~= x or x == math.huge or x == -math.huge then
error("Not a finite real number: " .. x)
end
return string.format("%.17g", x)
end
-- This function makes an effort to convert an arbitrary Lua value to a string
-- containing a JSON representation of it. It's not intended to be very robust,
-- but may be useful for prototyping.
function export.toJSON(val, opts)
opts = opts or {}
local function converter(val)
if type(val) == "nil" then
return "null"
elseif type(val) == "boolean" then
return val and "true" or "false"
elseif type(val) == "number" then
return export.json_fromNumber(val)
elseif type(val) == "string" then
return export.json_fromString(val)
elseif type(val) == "table" then
-- If the table has a toJSON member function, call that.
if val.toJSON then
return val:toJSON()
else
return export.json_fromTable(val, converter, opts)
end
else
error("Unsupported type: " .. type(val))
end
end
return converter(val)
end
local escape_char_map = {
["\\"] = "\\\\",
["\""] = "\\\"",
["\b"] = "\\b",
["\f"] = "\\f",
["\n"] = "\\n",
["\r"] = "\\r",
["\t"] = "\\t",
}
local function escape_char(c)
return escape_char_map[c] or string.format("\\u%04X", codepoint(c))
end
-- Given a string, escapes any illegal characters and wraps it in double-quotes.
-- Raises an error if the string is not valid UTF-8.
function export.json_fromString(s)
if type(s) ~= "string" or not mw.ustring.isutf8(s) then
error("Not a valid UTF-8 string: " .. s)
end
-- U+2029 (LINE SEPARATOR, \226\128\168 in UTF-8)
-- and U+2028 (PARAGRAPH SEPARATOR, \226\128\169 in UTF-8) are allowed
-- in JSON, but must be escaped for compatibility with JavaScript.
s = gsub(s, '[\\"%c\226\128\168\226\128\169]', escape_char)
return '"' .. s .. '"'
end
-- Given a table, treats it as an array and assembles its values in the form
-- "[ v1, v2, v3 ]". Optionally takes a function to JSONify the values before
-- assembly; if that function is omitted, then the values should already be
-- strings containing valid JSON data.
function export.json_arrayFromTable(val, converter, opts)
converter = converter or function (x) return x end
-- If `val` comes from mw.loadData() then #val is always 0, so deep copy to avoid this.
val = m_table.deepcopy(val)
local ret = {}
for i = 1, #val do
elem = converter(val[i])
if elem ~= nil then
table.insert(ret, elem)
end
end
if #ret == 0 then
return "[]"
end
return opts and opts.compress and "[" .. table.concat(ret, ",") .. "]" or
"[ " .. table.concat(ret, ", ") .. " ]"
end
-- Given a table whose keys are all strings, assembles its keys and values in
-- the form '{ "k1": v1, "k2": v2, "k3": v3 }'. Optionally takes a function to
-- JSONify the values before assembly; if that function is omitted, then the
-- values should already be strings containing valid JSON data. (The keys, by
-- contrast, should just be regular Lua strings; they will be passed to this
-- module's json_fromString.)
function export.json_fromTable(val, converter, opts)
converter = converter or function (x) return x end
local as_object = {}
local string_key = false
for key, value in pairs(val) do
value = converter(value)
if type(key) ~= "number" then
string_key = true
end
if value ~= nil then
key = export.json_fromString(tostring(key))
table.insert(as_object, key .. (opts and opts.compress and ":" or " : ") .. value)
end
end
if string_key then
return "{" .. table.concat(as_object, opts and opts.compress and "," or ", ") .. "}"
else
return export.json_arrayFromTable(val, converter, opts)
end
end
return export
