feat(frontends/lean): add "except" notation for "open" command, allow multiple metaclasses to be opened in a single "open" command

src/frontends/lean/builtin_cmds.cpp

@@ -445,6 +445,24 @@ static name parse_metaclass(parser & p) {
     }
 }
 
+static void parse_metaclasses(parser & p, buffer<name> & r) {
+    if (p.curr_is_token(get_sub_tk())) {
+        p.next();
+        buffer<name> tmp;
+        get_metaclasses(tmp);
+        tmp.push_back(get_decls_tk());
+        while (p.curr_is_token(get_lbracket_tk())) {
+            name m = parse_metaclass(p);
+            tmp.erase_elem(m);
+        }
+        r.append(tmp);
+    } else {
+        while (p.curr_is_token(get_lbracket_tk())) {
+            r.push_back(parse_metaclass(p));
+        }
+    }
+}
+
 static void check_identifier(parser & p, environment const & env, name const & ns, name const & id) {
     name full_id = ns + id;
     if (!env.find(full_id))
@@ -473,8 +491,13 @@ static environment add_abbrev(parser & p, environment const & env, name const &
 environment open_export_cmd(parser & p, bool open) {
     environment env = p.env();
     while (true) {
-        name cls = parse_metaclass(p);
-        bool decls = cls.is_anonymous() || cls == get_decls_tk() || cls == get_declarations_tk();
+        buffer<name> metacls;
+        parse_metaclasses(p, metacls);
+        bool decls = false;
+        if (metacls.empty() ||
+            std::find(metacls.begin(), metacls.end(), get_decls_tk()) != metacls.end() ||
+            std::find(metacls.begin(), metacls.end(), get_declarations_tk()) != metacls.end())
+            decls = true;
         auto pos   = p.pos();
         name ns    = p.check_id_next("invalid 'open/export' command, identifier expected");
         optional<name> real_ns = to_valid_namespace_name(env, ns);
@@ -487,9 +510,9 @@ environment open_export_cmd(parser & p, bool open) {
             as = p.check_id_next("invalid 'open/export' command, identifier expected");
         }
         if (open)
-            env = using_namespace(env, p.ios(), ns, cls);
+            env = using_namespace(env, p.ios(), ns, metacls);
         else
-            env = export_namespace(env, p.ios(), ns, cls);
+            env = export_namespace(env, p.ios(), ns, metacls);
         if (decls) {
             // Remark: we currently to not allow renaming and hiding of universe levels
             buffer<name> exceptions;

src/library/scoped_ext.cpp

@@ -80,24 +80,43 @@ bool is_metaclass(name const & n) {
     return false;
 }
 
-environment using_namespace(environment const & env, io_state const & ios, name const & n, name const & c) {
+environment using_namespace(environment const & env, io_state const & ios, name const & n, buffer<name> const & metaclasses) {
     environment r = env;
     for (auto const & t : get_exts()) {
-        if (c.is_anonymous() || c == std::get<0>(t))
+        if (metaclasses.empty() ||
+            std::find(metaclasses.begin(), metaclasses.end(), std::get<0>(t)) != metaclasses.end())
             r = std::get<1>(t)(r, ios, n);
     }
     return r;
 }
 
-environment export_namespace(environment const & env, io_state const & ios, name const & n, name const & c) {
+static environment using_namespace(environment const & env, io_state const & ios, name const & n, name const & metaclass) {
+    buffer<name> tmp;
+    if (!metaclass.is_anonymous())
+        tmp.push_back(metaclass);
+    return using_namespace(env, ios, n, tmp);
+}
+
+environment using_namespace(environment const & env, io_state const & ios, name const & n) {
+    buffer<name> metaclasses;
+    return using_namespace(env, ios, n, metaclasses);
+}
+
+environment export_namespace(environment const & env, io_state const & ios, name const & n, buffer<name> const & metaclasses) {
     environment r = env;
     for (auto const & t : get_exts()) {
-        if (c.is_anonymous() || c == std::get<0>(t))
+        if (metaclasses.empty() ||
+            std::find(metaclasses.begin(), metaclasses.end(), std::get<0>(t)) != metaclasses.end())
             r = std::get<2>(t)(r, ios, n);
     }
     return r;
 }
 
+environment export_namespace(environment const & env, io_state const & ios, name const & n) {
+    buffer<name> metaclasses;
+    return export_namespace(env, ios, n, metaclasses);
+}
+
 optional<name> to_valid_namespace_name(environment const & env, name const & n) {
     scope_mng_ext const & ext = get_extension(env);
     if (ext.m_namespace_set.contains(n))

src/library/scoped_ext.h

@@ -23,11 +23,14 @@ typedef environment (*push_scope_fn)(environment const &, scope_kind);
 typedef environment (*pop_scope_fn)(environment const &, scope_kind);
 
 void register_scoped_ext(name const & n, using_namespace_fn use, export_namespace_fn ex, push_scope_fn push, pop_scope_fn pop);
-/** \brief Use objects defined in the namespace \c n. If \c c is not the anonymous name, then only objects from "class" \c c are considered. */
-environment using_namespace(environment const & env, io_state const & ios, name const & n, name const & c = name());
+/** \brief Use objects defined in the namespace \c n.
+    If \c metaclasses is not empty, then only objects in the given "metaclasses" \c c are considered. */
+environment using_namespace(environment const & env, io_state const & ios, name const & n, buffer<name> const & metaclasses);
+environment using_namespace(environment const & env, io_state const & ios, name const & n);
 /** \brief Export objects defined in the namespace \c n to current namespace.
-    If \c c is not the anonymous name, then only objects from "class" \c c are considered. */
-environment export_namespace(environment const & env, io_state const & ios, name const & n, name const & c = name());
+    If \c metaclasses is not empty, then only objects in the given "metaclasses" \c c are considered. */
+environment export_namespace(environment const & env, io_state const & ios, name const & n, buffer<name> const & metaclasses);
+environment export_namespace(environment const & env, io_state const & ios, name const & n);
 
 /** \brief Create a new scope, all scoped extensions are notified. */
 environment push_scope(environment const & env, io_state const & ios, scope_kind k, name const & n = name());

tests/lean/open_tst.lean

@@ -0,0 +1,42 @@
+context
+  open [notations] [coercions] nat
+  check 1 + 2
+  check add -- Error aliases were not created
+end
+
+context
+  open [declarations] [notations] nat
+  variable a : nat
+  check a + a
+  check add a a
+  check a + 1 -- Error coercion from num to nat was not loaded
+end
+
+context
+  open - [classes] nat
+  variable a : nat
+  check a + a
+  check add a a
+  check a + 1
+  definition foo1 : inhabited nat :=
+  _ -- Error inhabited instances was not loaded
+end
+
+context
+  open - [classes] [decls] nat
+  variable a : nat
+  check a + a
+  check add a a -- Error aliases were not created
+  check a + 1
+  definition foo2 : inhabited nat :=
+  _ -- Error inhabited instances was not loaded
+end
+
+context
+  open [classes] nat
+  definition foo3 : inhabited nat :=
+  _
+
+  variable a : nat
+  check a + a -- Error notation declarations were not loaded
+end

tests/lean/open_tst.lean.expected.out

@@ -0,0 +1,29 @@
+1 + 2 : ℕ
+open_tst.lean:4:8: error: unknown identifier 'add'
+a + a : ℕ
+a + a : ℕ
+open_tst.lean:12:10: error: type mismatch at application
+  a + 1
+term
+  1
+has type
+  num
+but is expected to have type
+  ℕ
+a + a : ℕ
+a + a : ℕ
+a + 1 : ℕ
+open_tst.lean:22:2: error: don't know how to synthesize placeholder
+
+⊢ inhabited ℕ
+open_tst.lean:22:2: error: failed to add declaration 'foo1' to environment, value has metavariables
+  ?M_1
+a + a : ℕ
+open_tst.lean:29:8: error: unknown identifier 'add'
+a + 1 : ℕ
+open_tst.lean:32:2: error: don't know how to synthesize placeholder
+
+⊢ inhabited ℕ
+open_tst.lean:32:2: error: failed to add declaration 'foo2' to environment, value has metavariables
+  ?M_1
+open_tst.lean:41:10: error: invalid expression