49 lines
1.5 KiB
Markdown
49 lines
1.5 KiB
Markdown
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# Assert Gooder #
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_Lua_ library implementing an alternative version of Lua's `assert` function,
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giving much better error messages, when asserts fails. It does this by analysing
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the body of the assert, and figuring out what the failing assert call is
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attempting to test against.
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## Example
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```lua
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function f (a)
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assert(type(a) == 'string')
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end
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f(42)
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```
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Without `assert-gooder`, the above code would fail with the error message
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`assertion failed!`. With `assert-gooder`, it will fail with this error message:
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`assertion failed! bad argument #1 'a' to 'f' (string expected, but got number: 42)`,
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## Motivation
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Assertions are useful to ensure internal consistency, when you're writing code
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in a hurry, but in Lua (and most other languages), these assert constructs never
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produce useful error messages, but rather unhelpful `assert failed!` errors and
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a stack trace.
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By making it a runtime library, instead of a "compile-time" rewrite, we gain
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flexibility. It's much easier to import a library, than restructuring then
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compile pipeline. It also means that we have access to runtime values, allowing
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even more helpful messages.
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## Setup
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Download, and use `assert = require "assert-gooder"` to overwrite Lua's default
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assert with `assert-gooder`.
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## License
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```
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"THE BEER-WARE LICENSE" (Revision 42):
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<jonjmaa@gmail.com> wrote this library. As long as you retain this notice you
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can do whatever you want with this stuff. If we meet some day, and you think
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this stuff is worth it, you can buy me a beer in return.
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```
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