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2026-04-21T11:22:49Z

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wikt>Theknightwho: Protected "Module:fun/trycall": Highly visible template/module ([Edit=Allow only template editors and administrators] (indefinite) [Move=Allow only template editors and administrators] (indefinite))

2025-05-09T20:52:16Z

Protected "Module:fun/trycall": Highly visible template/module ([Edit=Allow only template editors and administrators] (indefinite) [Move=Allow only template editors and administrators] (indefinite))

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local fun_is_callable_module = "Module:fun/isCallable"

local error = error
local format = string.format
local pcall = pcall
local type = type

local function is_callable(...)
is_callable = require(fun_is_callable_module)
return is_callable(...)
end

local function catch_values(obj, success, ...)
if success then
return success, ...
-- Error message will only take this exact form if `obj` is not callable,
-- because it will contain a traceback if it was thrown further up the
-- stack.
elseif (...) == format("attempt to call a %s value", type(obj)) then
return false
end
return error(...)
end

--[==[
A special form of {pcall()}, which returns {true} plus the result value(s) if {obj} is callable, or {false} if it isn't. Errors that occur within the called function are not protected.]==]
return function(obj, ...)
local callable = is_callable(obj, true)
if callable then
return true, obj(...)
elseif callable == false then
return false
end
-- If `callable` is nil, there's a protected metatable, so there's no way to
-- check without doing a protected call.
return catch_values(obj, pcall(obj, ...))
end

Module:fun/trycall - Revision history

Sware: 1 revision imported

wikt>Theknightwho: Protected "Module:fun/trycall": Highly visible template/module ([Edit=Allow only template editors and administrators] (indefinite) [Move=Allow only template editors and administrators] (indefinite))