| > Maybe they are implemented similarly under the hood It's hard to know what to say to this. Tagged unions are not tagged unions, even if they are literal tagged unions? What? I reiterate what I said in my previous comment, you're not using the ordinary definition of the term union, and this is causing confusion. A union may or may not be a "union" as understood within various academic type theories, that really depends on how any given theory defines that word, which can be any way it wants. But a union is a CS concept with a clearly understood meaning, and when used without added context to suggest it is to be interpreted in some theoretical way, it is understood in that ordinary way. OP's article is clearly using 'union' to mean tagged unions - he even shows off their implementation, with a tag. The author assumes that his audience will understand what he's talking about when he uses the word union, and it's not causing anyone trouble in this comments section. The fact that alternative definitions within various theoretical paradigms is very nice, bless their hearts, but not really relevant. You may prefer other definitions to the usual CS definition, that's certainly your prerogative, but - again - that's hardly grounds for taking an article and comment section that's using the commonplace meaning, and appearing to lecture others for failing to adhere to your idiosyncratic standards for what a union must be. |