Module:CallAssert/doc
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 | 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 provides function callAssert, which simplifies error checking by throwing an error if a given function returns nil or false. This is similar to the built-in function assert, but unlike it, callAssert itself calls the function, whose return value is to be checked. This allows it to include the function name and argument values in the error message.
Usage
local callAssert = require('Module:CallAssert')
local result1, result2, etc = callAssert(func, 'funcName', ...)
callAssert calls func(...) and checks if the first returned value evaluates to true. If it does, then it returns all the returned values. If not, it throws an error with a message in the form 'funcName(argument_values) failed'.