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Comment by BlargMcLarg | Hacker News Reader

>Wrap All Primitives And Strings

Gah. I've seen the other side of this, a few people far too trigger happy to make FivePlusVeryLongNounVO/DTO for every little thing, and it gave me some new appreciation towards tuples and primitives. Sometimes you really don't want to go into another new file for an object type which is used in only one specific place. Especially with

>Don’t Abbreviate

Meaning the variable name will end up long anyway. With tuples, you get deconstruction without the hassle, too.

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> Gah. I've seen the other side of this, a few people far too trigger happy to make FivePlusVeryLongNounVO/DTO for every little thing, and it gave me some new appreciation towards tuples and primitives. Sometimes you really don't want to go into another new file for an object type which is used in only one specific place.

The rules are an exercise for a toy project. Like all similar 'rules' they are just hints to make you think. When done with the exercise, and you see a string with a social security number in a production code, you may consider creating a dedicated SocialSecurityNumber class. The class will guarantee a well formed social security number according to official rules. The class may even offer Area, Group and Serial parts of the social as separate fields. The class may decide to use a string or integers internally, but that would never be exposed to the class consumers. All the code that uses SocialSecurityNumber will not have to guess whether string is valid, if it has dashes etc. The same reason you use built-in types like an Integer (as oppose to a tuple of 4 bytes or 32 bits).

Your example breaks down the moment you put it back in context. SocialSecurityNumber works because it's going to be used across multiple subcontexts. The same reason Vector2 works over using (x, y) tuples everywhere.

I'm specifically mentioning one specific place. This now requires you to go to a different file to see what's up, for every time you need HighlySpecificModelWithOnlyStringAndInt, and most naming doesn't help provide context. All that's happening here is moving vertical navigation to navigating different files. It's a remnant of a time people wanted more specification than object[], but valuetuples didn't exist yet (C#).

And even then, SSN is a pretty well known abbreviation. So your example is also far too favorable compared to most extreme yet real examples.

You seem to be fixated at knowing what objects consist of and you seem to stop at a fairly arbitrary level - primitives provided by the language (int, string etc). Why not go all the way down to bits? I find that a well designed Value object [0] makes me more productive because I specifically don't need to know how it is implemented internally, only the exposed interface. Examples:

ZonedDateTime

PhoneNumber

SocialSecurity

Guid

EmailAddress

Point

Url

ExpiredCoupon

Regarding one specific place, if I only need to know date time and its zone in one specific place, would you recommend Tuple<int, int, int, int, int, int, int, string> instead of ZonedDateTime?

[0] https://martinfowler.com/bliki/ValueObject.html

[1] https://docs.oracle.com/javase/8/docs/api/java/time/ZonedDat...

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