As I posted on Github, I don’t think it’s a horrible change as long as the language server/IDE plugins gets an easy flag for Unicode.
But it’s not clear to me that this doesn’t fail to solve (or even compound) the issue. Changing the behavior of
dhall format presupposes that the newcomer has discovered the existence of
dhall format, at which point the Unicode syntax would be a non-issue. And if
dhall format uses ASCII by default, and a newcomer comes across a file with Unicode syntax, then copy-pasting is actually the only way for them to edit it (barring a potentially obscure flag). Not to mention this necessitating changing literally every file in the Prelude (and a lot of files in the standard), though those shouldn’t be semantic hash-affecting, thankfully.
Honestly, I see this as potentially fracturing the community (not in an argument sense, haha), just in terms of then running into half of files formatted in one way and half in the other, which invariably becomes a pain to work with. (See also line-endings, spaces vs tabs, braces on the same line or next, etc. etc. etc.)
At the end of the day, I guess I come down on the Unicode side for the following reason: It’s hard to write Unicode syntax without
dhall format, but it’s not hard to write ASCII syntax without it. If it’s going to be horribly annoying to use Unicode syntax, then it’s not really clear why it should be supported at all. (Yes, of course, there’d be a flag for it, but at that point it doesn’t seem to be anything but an afterthought.)
As I said on the github issue, I do wonder if it’d be better in the long run to instead focus more on introducing
dhall format/Unicode syntax to newcomers. Honestly,
dhall format could be made a selling point on the home page (never worry about formatting again!). Anyways, I talked a bit about that there, so I won’t repeat myself here.