Parse, Don't Validate (2019)
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Parse, Don't Validate (2019)
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Re: Parse, Don't Validate (2019)
#2Maybe I'm missing something and I'm glad this idea resonates, but it feels like sometime after Java got popular and dynamic languages got a lot of mindshare, a large chunk of the collective programming community forgot why strong static type checking was invented and are now having to rediscover this.
In most strong statically typed languages, you wouldn't often pass strings and generic dictionaries around. You'd naturally gravitate towards parsing/transforming raw data into typed data structures that have guaranteed properties instead to avoid writing defensive code everywhere e.g. a Date object that would throw an exception in the constructor if the string given didn't validate as a date (Edit: Changed this from email because email validation is a can of worms as an example). So there, "parse, don't validate" is the norm and not a tip/idea that would need to gain traction.
Re: Parse, Don't Validate (2019)
#3A frequent visitor to HN. Tip: if you click on the "past" link under the title (but not the "past" link at the top of the page), you'll trigger a search for previous posts.
https://hn.algolia.com/?query=Parse%2C%20Don%27t%20Validate&...
However, it's more effective to throw quotes into the mix, reduces false positives.
https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
Re: Parse, Don't Validate (2019)
#4Each repost is worth it.
This, along with John Ousterhout's talk [1] on deep interfaces was transformational for me. And this is coming from a guy who codes in python, so lots of transferable learnings.
Re: Parse, Don't Validate (2019)
#5Maybe I'm missing something and I'm glad this idea resonates, but it feels like sometime after Java got popular and dynamic languages got a lot of mindshare, a large chunk of the collective programming community forgot why strong static type checking was invented and are now having to rediscover this. In most strong statically typed languages, you wouldn't often pass strings and generic dictionaries around. You'd nat…
In my experience that's pretty rare. Most people pass around string phone numbers instead of a phonenumber class.
Java makes it a pain though, so most code ends up primitive obsessed. Other languages make it easier, but unless the language and company has a strong culture around this, they still usually end up primitive obsessed.
Re: Parse, Don't Validate (2019)
#6Maybe I'm missing something and I'm glad this idea resonates, but it feels like sometime after Java got popular and dynamic languages got a lot of mindshare, a large chunk of the collective programming community forgot why strong static type checking was invented and are now having to rediscover this. In most strong statically typed languages, you wouldn't often pass strings and generic dictionaries around. You'd nat…
It's a design choice more than anything. Haskell's type safety is opt-in — the programmer has to actually choose to properly leverage the type system and design their program this way.
Re: Parse, Don't Validate (2019)
#7Maybe I'm missing something and I'm glad this idea resonates, but it feels like sometime after Java got popular and dynamic languages got a lot of mindshare, a large chunk of the collective programming community forgot why strong static type checking was invented and are now having to rediscover this. In most strong statically typed languages, you wouldn't often pass strings and generic dictionaries around. You'd nat…
> In most strong statically typed languages, you wouldn't often pass strings and generic dictionaries around.
In 99% of the projects I worked on my professional life, anything that is coming from an human input is manipulated as a string and most of the time, it stays like this in all of the application layers (with more or less checks in the path).
On your precise exemple, I can even say that I never saw something like an "Email object".
Re: Parse, Don't Validate (2019)
#8Maybe I'm missing something and I'm glad this idea resonates, but it feels like sometime after Java got popular and dynamic languages got a lot of mindshare, a large chunk of the collective programming community forgot why strong static type checking was invented and are now having to rediscover this. In most strong statically typed languages, you wouldn't often pass strings and generic dictionaries around. You'd nat…
In my experience that's pretty rare. Most people pass around string phone numbers instead of a phonenumber class. Java makes it a pain though, so most code ends up primitive obsessed. Other languages make it easier, but unless the language and company has a strong culture around this, they still usually end up primitive obsessed.
record PhoneNumber(String value) {}
Re: Parse, Don't Validate (2019)
#9Semi tangent but I am curious. for those with more experience in python, do you just pass around generic Pandas Dataframes or do you parse each row into an object and write logic that manipulates those instead?
Re: Parse, Don't Validate (2019)
#10I did a lightning talk on this topic last year, with a concrete example in Yesod.