Hi, Am Montag, den 07.09.2015, 19:25 +0000 schrieb Simon Peyton Jones:
Are we okay with stealing some operator sections for this? E.G. (x
). I think the boxed sums larger than 2 choices are all technically overlapping with sections.
I hadn't thought of that. I suppose that in distfix notation we could require spaces (x | |) since vertical bar by itself isn't an operator. But then (_||) x might feel more compact.
Also a section (x ||) isn't valid in a pattern, so we would not need to require spaces there.
But my gut feel is: yes, with AnonymousSums we should just steal the syntax. It won't hurt existing code (since it won't use AnonymousSums), and if you *are* using AnonymousSums then the distfix notation is probably more valuable than the sections for an operator you probably aren't using.
I wonder if this syntax for constructors is really that great. Yes, you there is similarly with the type constructor (which is nice), but for the data constructor, do we really want an unary encoding and have our users count bars? I believe the user (and also us, having to read core) would be better served by some syntax that involves plain numbers. Given that of is already a keyword, how about something involving "3 of 4"? For example (Put# True in 3 of 5) :: (# a | b | Bool | d | e #) and case sum of (Put# x in 1 of 3) -> ... (Put# x in 2 of 3) -> ... (Put# x in 3 of 3) -> ... (If "as" were a keyword, (Put# x as 2 of 3) would sound even better.) I don’t find this particular choice very great, but something with numbers rather than ASCII art seems to make more sense here. Is there something even better? Greetings, Joachim -- Joachim “nomeata” Breitner mail@joachim-breitner.de • http://www.joachim-breitner.de/ Jabber: nomeata@joachim-breitner.de • GPG-Key: 0xF0FBF51F Debian Developer: nomeata@debian.org