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Stop writing CLI validation. Parse it right the first time

(hackers.pub)
203 points dahlia | 1 comments | 06 Sep 25 18:20 UTC | HN request time: 0s | source
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12_throw_away ◴[07 Sep 25 01:29 UTC] No.45154518[source]▶
I like this advice, and yeah, I always try to make illegal states unrepresentable, possibly even to a fault.

The problem I run into here is - how do you create good error messages when you do this? If the user has passed you input with multiple problems, how do you build a list of everything that's wrong with it if the parser crashes out halfway through?

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1. akoboldfrying ◴[07 Sep 25 01:46 UTC] No.45154627[source]▶
Agree. It should definitely be possible to get error messages on par with what TypeScript gives you when you try to assign an object literal to an incompatibly typed variable; whether that's currently the case, and how difficult it would be to get there if not, I don't know.