Various bugfixes and improvements

- Rename DeIid to Operator. It corresponds to operator <string> in the
  syntax. The previous name is from when it was called deinfix in
  sail1.

- Removed things that weren't actually common from
  pretty_print_common.ml, e.g. printing identifiers is backend
  specific. The doc_id function here was only used for a very specific
  use case in pretty_print_lem, so I simplified it and renamed it to
  doc_sia_id, as it is always used for a SIA.Id whatever that is.

- There is some support for anonymous records in constructors, e.g.

  union Foo ('a : Type) = {
    MkFoo : { field1 : 'a, field2 : int }
  }

  somewhat similar to the enum syntax in Rust. I'm not sure when this
  was added, but there were a few odd things about it. It was
  desugared in the preprocessor, rather than initial_check, and the
  desugaring generated incorrect code for polymorphic anonymous
  records as above.

  I moved the code to initial_check, so the pre-processor now just
  deals with pre-processor things and not generating types, and I
  fixed the code to work with polymorphic types. This revealed some
  issues in the C backend w.r.t. polymorphic structs, which is the
  bulk of this commit. I also added some tests for this feature.

- OCaml backend can now generate a valid string_of function for
  polymorphic structs, previously this would cause the ocaml to fail
  to compile.

- Some cleanup in the Sail ott definition

- Add support for E_var in interpreter previously this would just
  cause the interpreter to fail

6 files changed, 56 insertions, 0 deletions

diff --git a/test/c/anon_rec.expect b/test/c/anon_rec.expect
new file mode 100644
index 00000000..9766475a
--- /dev/null
+++ b/test/c/anon_rec.expect
@@ -0,0 +1 @@
+ok
diff --git a/test/c/anon_rec.sail b/test/c/anon_rec.sail
new file mode 100644
index 00000000..17dd1e07
--- /dev/null
+++ b/test/c/anon_rec.sail
@@ -0,0 +1,12 @@
+default Order dec
+
+union Foo ('a : Type) = {
+  MkFoo : { field1 : 'a, field2 : int }
+}
+
+val "print_endline" : string -> unit
+
+function main((): unit) -> unit = {
+  let _: Foo(unit) = MkFoo(struct { field1 = (), field2 = 22 });
+  print_endline("ok")
+}
diff --git a/test/c/poly_int_record.expect b/test/c/poly_int_record.expect
new file mode 100644
index 00000000..a8a10253
--- /dev/null
+++ b/test/c/poly_int_record.expect
@@ -0,0 +1,3 @@
+x = 1
+y = 2
+ok
diff --git a/test/c/poly_int_record.sail b/test/c/poly_int_record.sail
new file mode 100644
index 00000000..ebb18713
--- /dev/null
+++ b/test/c/poly_int_record.sail
@@ -0,0 +1,21 @@
+default Order dec
+
+val "print_endline" : string -> unit
+val "print_int" : (string, int) -> unit
+
+struct S('a: Type) = {
+  field1 : ('a, 'a),
+  field2 : unit
+}
+
+function main((): unit) -> unit = {
+  var s : S(range(0, 3)) = struct { field1 = (0, 3), field2 = () };
+  s.field1 = (1, 2);
+  match s.field1 {
+    (x, y) => {
+      print_int("x = ", x);
+      print_int("y = ", y);
+    }
+  };
+  print_endline("ok");
+}
diff --git a/test/c/poly_record.expect b/test/c/poly_record.expect
new file mode 100644
index 00000000..9766475a
--- /dev/null
+++ b/test/c/poly_record.expect
@@ -0,0 +1 @@
+ok
diff --git a/test/c/poly_record.sail b/test/c/poly_record.sail
new file mode 100644
index 00000000..afe1f144
--- /dev/null
+++ b/test/c/poly_record.sail
@@ -0,0 +1,18 @@
+default Order dec
+
+val "print_endline" : string -> unit
+
+struct S('a: Type) = {
+  field1 : 'a,
+  field2 : unit
+}
+
+function f forall ('a :Type). (s: S('a)) -> unit = {
+  s.field2
+}
+
+function main((): unit) -> unit = {
+  let s : S(unit) = struct { field1 = (), field2 = () };
+  f(s);
+  print_endline("ok");
+}