Assert Gooder

Supercharged assert replacement.

Lua Library that replaces the default assert function with one that can emit improved error messages. The improved assert function parses the assert condition, inspects the state of the program and emits an improved error message.

Example

function f (a)

assert(type(a) == 'string')

 end

 f(42)

Without assert-gooder, the above code would fail with the error message assertion failed!. With assert-gooder, it will fail with this error message: assertion failed! bad argument #1 'a' to 'f' (string expected, but got number: 42),

Motivation

Assertions are useful to ensure internal consistency, when you're writing code in a hurry, but in Lua (and most other languages), these assert constructs never produce useful error messages, but rather unhelpful assert failed! errors and a stack trace.

By making it a runtime library, instead of a "compile-time" rewrite, we gain flexibility. It's much easier to import a library, than restructuring then compile pipeline. It also means that we have access to runtime values, allowing even more helpful messages.

Setup

Download, and use assert = require "assert-gooder" to overwrite Lua's default assert with assert-gooder.

• Author: Jon Michael Aanes (jonjmaa@gmail.com)

Dependencies

This project requires PUC Lua 5.1 or LuaJIT. Newer versions of PUC Lua are not supported.

This project does not have any library requirements 😎

Contributing

Feel free to submit pull requests. Please follow the Code Conventions when doing so.

License

MIT License

Copyright (c) 2017-2025 Jon Michael Aanes

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
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furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
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