> Still weird to have a syntax that is at odds with the underlying semantics, and hopefully it doesn't sow more confusion than it initially solves in the long term
_This_, I do think, is a fair argument. It's indeed an accidental drawback of the syntax revamp. Though there are very realistic way to prevent the confusion: https://github.com/reasonml-community/error-message-improvem...
Regarding optimization: see the BuckleScript link on explicit uncurrying. The impact is very visible: the compiler analysis for specializing for uncurrying best-effort, and when it bails, it looks like this: https://reasonml.github.io/try/?reason=PQKgBA5g9lAmYGMCGBnAp... which calls https://github.com/BuckleScript/bucklescript/blob/2a66960b5a.... How many function calls did your curried call just turn into, in the second case?
Unless you introspect the output (which is actually viable to do in a compiler with clean output, such as BuckleScript), you wouldn't know that your higher-order function accidentally became pretty much 4+ calls instead of one. Now imagine quadrupling every high-order function calls or so. BucklesScript (and native OCaml) do a crazy good job of avoiding this when possible, more so than most, as shown in the snippet's first scenario; the manual even shows guaranteed uncurry if you put the right annotation. But if you want to take advantage of _that_ (and please do), there are other tradeoffs as well, but I digress. In general, the compiled code's speed is as good as you can get for JS output.
The perf point alone is not a pedantic argument as you can see. And you might start wondering about other languages' output for currying. Regarding your other comment: yes, from a typing perspective, currying indeed works out wonderfully for pure languages like Elm and PureScript. But OCaml's not a pure language; we've made other tradeoffs; and context matters.
Not sure about your comment about the AST, but I think you're saying that the situation doesn't get better/worse in the new syntax: this is true, since the syntax revamp is really just that: a syntax change. Which is why I said earlier that I was arguing beside the point. But currying seems to attract so much unbalanced attention in this context that I felt I should address it so that it doesn't overwhelm the rest of the syntax change's purpose. Looking at the rest of the threads, it still did, but I'm glad your reaction has been doubt rather than unreasoned negativity, so thanks for that.