Union Types and Option Types (2025)

ks2048 an hour ago | parent | next [-]

What is the best source for cross-language description of language features? Eg: “optional types”: which langs have them and how do they work? Same with “union types” etc.

	▲	tylermk04 23 minutes ago \| parent [-]
		Rosetta code is often helpful. Not exactly for language features, necessarily: https://rosettacode.org/wiki/Monads/Maybe_monad

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p1necone an hour ago | parent | prev | next [-]

One simple but non obvious (at least to me) trick when implementing tagged unions: put the union discriminator/tag at the end, not the beginning - that way a pointer to a union is also a pointer to the value, no need to increment the pointer to point past the tag after discriminating.

	▲	beached_whale 9 minutes ago \| parent [-]
		when serializing these things it's generally going to be best to put the tag first though. That way it's cheap to figure out how to parse it.

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gnabgib a day ago | parent | prev | next [-]

(2025) And about CopperLang (203 points, 3 days ago, 120 comments) https://news.ycombinator.com/item?id=50308754

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direwolf20 2 hours ago | parent | prev | next [-]

i read Onion Types

	▲	budro 2 minutes ago \| parent \| next [-]
		Well poor design can require you to peel off multiple layers of optionals, and so they're often a significant smell just like onions are.
	▲	SoleilAbsolu an hour ago \| parent \| prev [-]
		So shallot be...

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2 hours ago | parent | prev [-]

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