Skip to content

experiment: use inner named type to disambiguate and wild card for anonymous matches #5525

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Closed
Parent: experiment: add `implicit` keyword and dedicated grammar
wants to merge 1 commit into from
Closed

experiment: use inner named type to disambiguate and wild card for anonymous matches #5525

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 4 additions & 1 deletion doc/md/examples/grammar.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,9 @@
<implicit> ::=
'implicit'

<id_wild> ::=
'_'

<typ_obj_sort> ::=
'object'
'actor'
Expand Down Expand Up @@ -70,8 +73,8 @@
<typ> 'or' <typ>

<typ_item> ::=
<implicit> <typ>
Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Why has this disappeared?

<id> ':' <typ>
<id_wild> ':' <typ>
<typ>

<typ_args> ::=
Expand Down
4 changes: 4 additions & 0 deletions src/mo_frontend/parser.mly
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -368,6 +368,9 @@ seplist1(X, SEP) :
%inline implicit :
| IMPLICIT { "implicit" @@ at $sloc }

%inline id_wild :
| UNDERSCORE { "_" @@ at $sloc }

%inline typ_id :
| id=ID { id @= at $sloc }

Expand Down Expand Up @@ -486,6 +489,7 @@ typ :

typ_item :
| i=id COLON t=typ { Some i, t }
| i=id_wild COLON t=typ { Some i, t }
| t=typ { None, t }

typ_args :
Expand Down
22 changes: 15 additions & 7 deletions src/mo_frontend/typing.ml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2454,16 +2454,24 @@ and infer_callee env exp =
infer_exp_promote env exp, None

and insert_holes at ts es =
let mk_hole pos hole_id =
let hole_sort = if hole_id = "" then Anon pos else Named hole_id in
{it = HoleE (hole_sort, ref {it = PrimE "hole"; at; note=empty_typ_note });
at;
note = empty_typ_note }
in
let rec go n ts es =
match (ts, es) with
| (T.Named ("implicit", T.Named (arg_name, t))) :: ts1, es ->
(mk_hole n arg_name) :: go (n + 1) ts1 es
| (T.Named ("implicit", t)) :: ts1, es ->
{it = HoleE (Anon n, ref {it = PrimE "hole"; at; note=empty_typ_note });
at;
note = empty_typ_note } :: go (n+1) ts1 es
| (T.Named (arg_name, (T.Named ("implicit", t)))) :: ts1, es ->
{it = HoleE (Named arg_name, ref {it = PrimE "hole"; at; note=empty_typ_note });
at;
note = empty_typ_note } :: go (n+1) ts1 es
(mk_hole n "_") :: go (n + 1) ts1 es
| (T.Named (_inf_arg_name, (T.Named ("implicit", T.Named (arg_name, t))))) :: ts1, es ->
(* override inferred arg_name *)
(mk_hole n arg_name) :: go (n + 1) ts1 es
| (T.Named (inf_arg_name, (T.Named ("implicit", t)))) :: ts1, es ->
(* non-overriden, use inferred arg_name *)
(mk_hole n inf_arg_name) :: go (n + 1) ts1 es
| (t :: ts1, e::es1) -> e :: go (n+1) ts1 es1
| _, [] -> []
| [], es -> es
Expand Down
14 changes: 14 additions & 0 deletions test/fail/implicit.mo
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -86,3 +86,17 @@ func mkZero<T>(zero : implicit T) : T {
};

ignore mkZero<{ x : Nat }>();

// tricky case: if we have two implicit arguments of the same name we currently need to add a second type annotation
func c <T, U>(p1 : (T, U), p2 : (T, U),
cT : implicit (c : (T, T) -> Order),
cU : implicit (c : (U, U) -> Order))
: Order {
switch (cT(p1.0, p2.0)) {
case (#equal) { cU(p1.1, p2.1) };
case ord { ord };
};
};

ignore c((1,"a"),(0,"b")); // accepted

Loading