On 11-12-20 02:55 PM, Elly Jones wrote:
2. The dot after the nullary tag. In general I want to write a nullary tag a LOT
more often than I want to write a wildcard binder, so I feel like this is the
wrong way for this choice to go, but I'll understand if this is a decided issue
already.
Agreed. There's a wiki page showing options on this.
3. The use of alt in situations which would be handled with a guard clause in C.
For example, in C, I might write:
...
let bar(mybar) = foo else { fail "OOPS"; }
This is called a "refutable pattern" in some languages and .. I'd be
somewhat-ok with adding it as a way to do a let-destructuring in
general, w/o an else clause. Just treat it as an implicit fail
(reporting location) the way we do a fallthrough in an alt.
Hermes did something interesting here, which is that a variant type
defined typestate predicates along the lines of "value x is variant y",
so you could check one and make it a typestate precondition. I'm not
sure that's any less syntactically awkward though.
4. I wish a lot more of the standard library was object-oriented. I realize this
is somewhat of a slippery slope, but writing 'vec::len(thing)' is less nice (to
me) than thing.len(). I think that things in the standard library that are
object-like (vec, str, ...) should be objects.
Typeclasses will probably give us a hammer to hit a lot of this stuff with.
5. I do not like the mk_foo()/obj foo {} idiom; it forces code another tabstop
to the right.
And this.
6. Having to export all the members of a tag you're exporting seems bizarre;
when would you ever want the tag but not its members?
When you want a nominal type that you want to Greatly Discourage clients
from trying to construct or inspect themselves.
I think we can probably do something with globbing here though. I don't
mind making "export tagname::*" mean "export all the constructors". It's
a special case in the export-glob logic but not a particularly
strange-looking one.
-Graydon
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