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This metamodule simplifies error handling in other modules. It transforms a function, which may throw an error, into a function, which returns a specified error message in that case.
Usage
local protect = require('Module:Protect')
local protectedFunc = protect(func, errFormat, options)
Arguments
func
- Function to be transformed.
errFormat
(default:'Error: %s'
)- Custom error message.
- Use
'%s'
to include the message from a caught error.
options
– optional table with the following fields:raw
(default: false)- If true, then
errFormat
will be used as is, otherwise it will be wrapped inside a tag<strong class="error">
.
- If true, then
removeLocation
(default: true)- If true, removes location information from caught error messages.
Return value
The resulting protectedFunc
is a function, which calls the original function func
, passing all arguments to it, and returns all its return values. If func
throws an error, the specified error message is returned instead.
Example
local protect = require('Module:Protect')
local p = {}
function p.main(frame)
if not frame.args[1] then
error('missing argument')
end
return frame.args[1]
end
p.main = protect(p.main)
return p
Invoking the main function without arguments will output: Error: missing argument
local function processResult(options, success, ...)
if not success then
local message = tostring(... or '(no message)')
if options.removeLocation then
message = string.gsub(message, '^Module:[^:]+:%d+: ', '', 1)
end
return string.format(options.errFormat, message)
end
return ...
end
local function protect(func, errFormat, options)
if type(errFormat) == 'table' then
options = options or errFormat
errFormat = nil
end
options = mw.clone(options) or {}
options.errFormat = errFormat or options.errFormat or 'Error: %s'
if not options.raw then
options.errFormat = '<strong class="error">' .. options.errFormat .. '</strong>'
end
options.removeLocation = options.removeLocation == nil or options.removeLocation
return function (...)
return processResult(options, pcall(func, ...))
end
end
return protect