Module:Protect/doc

This is a documentation subpage for Module:Protect.
It may contain usage information, categories and other content that is not part of the original module page.

This module is rated as alpha. It is ready for limited use and third-party feedback. It may be used on a small number of pages, but should be monitored closely. Suggestions for new features or adjustments to input and output are welcome.

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, raw)

Arguments

func
Function to be transformed.
errFormat (optional)
Custom error message.

Use '%s' to include the message from a caught error.

Default: 'Error: %s'
raw (optional)
If true, then errFormat will be used as is, otherwise it will be wrapped inside a tag <strong class="error">.

Default: false

Return value

The resulting protectedFunc is a function, which calls the original function func, passing all arguments to it and returning 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', 0)  -- The zero prevents including location information
    end
    return frame.args[1]
end

p.main = protect(p.main)

return p

Invoking the main function without arguments will output: Error: missing argument