Sware: Created page with "--[=[ Throw an error for an invalid language code or script code. `code` (required) is the bad code and can be nil or a non-string. `param` (required) is the name of the parameter in which the code was contained. It can be a string, a number (for a numeric param, in which case the param will show up in the error message as an ordinal such as "first" or "second"), or `true` if no parameter can be clearly identified. It can also be a function of one argument (an error..."

2026-05-13T10:39:41Z

Created page with "--[=[ Throw an error for an invalid language code or script code. `code` (required) is the bad code and can be nil or a non-string. `param` (required) is the name of the parameter in which the code was contained. It can be a string, a number (for a numeric param, in which case the param will show up in the error message as an ordinal such as "first" or "second"), or `true` if no parameter can be clearly identified. It can also be a function of one argument (an error..."

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--[=[
Throw an error for an invalid language code or script code.

`code` (required) is the bad code and can be nil or a non-string.

`param` (required) is the name of the parameter in which the code was contained. It can be a string, a number (for a
numeric param, in which case the param will show up in the error message as an ordinal such as "first" or "second"),
or `true` if no parameter can be clearly identified. It can also be a function of one argument (an error message) or
two arguments (an error message and a number of stack frames to ignore, same as in the error() function itself), in
which case the function will be called with the same error message as if `true` were passed in. (This is useful e.g.
when parsing inline modifiers, where the parameter name may not be available or may not be so clearly identifiable,
but an error function is often available.)

`code_desc` (optional) is text describing what the code is; by default, "language code".

`template_text` (optional) is a string specifying the template that generated the error, or a function
to generate this string. If given, it will be displayed in the error message.
]=]

local dump = mw.dumpObject

local function internal_err(param, types, param_type)
error(("Internal error: the parameter %s must be %s, but received %s"):format(dump(param), types, param_type))
end

return function(code, param, code_desc, template_tag)
local is_callable = require("Module:fun").is_callable

if param == nil then
param = true
end
if not code_desc then
code_desc = "language code"
end

if template_tag then
if is_callable(template_tag) then
template_tag = template_tag()
else
local template_tag_type = type(template_tag)
if template_tag_type ~= "string" then
internal_err("template_tag", "a function, callable table or nil", "a " .. template_tag_type)
end
end
template_tag = (" (original template: %s)"):format(template_tag)
else
template_tag = ""
end

local param_is_callable = is_callable(param)
local function err(msg)
msg = msg .. template_tag
if not(param_is_callable) then
error(require("Module:string utilities").ucfirst(msg) .. ".", 3)
end
param(msg, 3)
end

if not (param == true or param_is_callable) then
local param_type = type(param)
if not (param_type == "string" or param_type == "number") then
internal_err("param", "a number, string, function, callable table, true or nil", param == false and "false" or "a " .. param_type)
end
param = ("parameter %s "):format(dump(param))
end

if code == nil or code == "" then
if param == true or param_is_callable then
err(code_desc .. " is missing")
else
err(param .. "(" .. code_desc .. ") is missing")
end
else
local code_type = type(code)
if code_type ~= "string" then
internal_err("code", "a string or nil", "a " .. code_type)
end
end
err(("%smust be a valid %s; the value %s is not valid (see [[Wiktionary:List of languages]])"):format(
(param == true or param_is_callable) and "" or param, code_desc, dump(code)
))
end

Module:languages/error - Revision history