1.5 KiB
Assert Gooder
Lua library implementing an alternative version of Lua's assert function,
giving much better error messages, when asserts fails. It does this by analysing
the body of the assert, and figuring out what the failing assert call is
attempting to test against.
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.
License
"THE BEER-WARE LICENSE" (Revision 42):
<jonjmaa@gmail.com> wrote this library. As long as you retain this notice you
can do whatever you want with this stuff. If we meet some day, and you think
this stuff is worth it, you can buy me a beer in return.