47 lines
1.5 KiB
Markdown
47 lines
1.5 KiB
Markdown
# 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
|
|
|
|
```lua
|
|
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.
|
|
```
|