feat(frontends/lean/builtin_cmds): change notation for marking implicit/cast parameter in sections

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

src/frontends/lean/decl_cmds.cpp

@@ -16,7 +16,10 @@ Author: Leonardo de Moura
 
 namespace lean {
 static name g_llevel_curly(".{");
+static name g_lcurly("{");
 static name g_rcurly("}");
+static name g_lbracket("[");
+static name g_rbracket("]");
 static name g_colon(":");
 static name g_assign(":=");
 static name g_private("[private]");
@@ -38,6 +41,28 @@ environment universe_cmd(parser & p) {
     return env;
 }
 
+binder_info parse_open_binder_info(parser & p) {
+    if (p.curr_is_token(g_lcurly)) {
+        check_in_section(p);
+        p.next();
+        return mk_implicit_binder_info();
+    } else if (p.curr_is_token(g_lbracket)) {
+        check_in_section(p);
+        p.next();
+        return mk_cast_binder_info();
+    } else {
+        return binder_info();
+    }
+}
+
+void parse_close_binder_info(parser & p, binder_info const & bi) {
+    if (bi.is_implicit()) {
+        p.check_token_next(g_rcurly, "invalid declaration, '}' expected");
+    } else if (bi.is_cast()) {
+        p.check_token_next(g_rbracket, "invalid declaration, ']' expected");
+    }
+}
+
 bool parse_univ_params(parser & p, buffer<name> & ps) {
     if (p.curr_is_token(g_llevel_curly)) {
         p.next();
@@ -83,8 +108,9 @@ static environment declare_var(parser & p, environment env,
     }
 }
 
-environment variable_cmd_core(parser & p, bool is_axiom, binder_info const & bi) {
+environment variable_cmd_core(parser & p, bool is_axiom) {
     auto pos = p.pos();
+    binder_info bi = parse_open_binder_info(p);
     name n = p.check_id_next("invalid declaration, identifier expected");
     check_atomic(n);
     buffer<name> ls_buffer;
@@ -106,6 +132,7 @@ environment variable_cmd_core(parser & p, bool is_axiom, binder_info const & bi)
         p.next();
         type = p.parse_expr();
     }
+    parse_close_binder_info(p, bi);
     level_param_names ls;
     if (in_section(p.env())) {
         ls = to_level_param_names(collect_univ_params(type));
@@ -117,22 +144,10 @@ environment variable_cmd_core(parser & p, bool is_axiom, binder_info const & bi)
     return declare_var(p, p.env(), n, ls, type, is_axiom, bi, pos);
 }
 environment variable_cmd(parser & p) {
-    return variable_cmd_core(p, false, binder_info());
+    return variable_cmd_core(p, false);
 }
 environment axiom_cmd(parser & p)    {
-    return variable_cmd_core(p, true, binder_info());
+    return variable_cmd_core(p, true);
-}
-environment implicit_variable_cmd(parser & p) {
-    check_in_section(p);
-    return variable_cmd_core(p, false, mk_implicit_binder_info());
-}
-environment implicit_axiom_cmd(parser & p) {
-    check_in_section(p);
-    return variable_cmd_core(p, true, mk_implicit_binder_info());
-}
-environment cast_variable_cmd(parser & p) {
-    check_in_section(p);
-    return variable_cmd_core(p, false, mk_cast_binder_info());
 }
 
 // Sort local_names by order of occurrence in the section, and copy the associated parameters to section_ps
@@ -264,9 +279,10 @@ environment theorem_cmd(parser & p) {
     return definition_cmd_core(p, true, true);
 }
 
-static environment variables_cmd_core(parser & p, bool is_axiom, binder_info const & bi) {
+static environment variables_cmd(parser & p) {
     auto pos = p.pos();
     buffer<name> ids;
+    binder_info bi = parse_open_binder_info(p);
     while (!p.curr_is_token(g_colon)) {
         name id = p.check_id_next("invalid parameters declaration, identifier expected");
         check_atomic(id);
@@ -278,37 +294,23 @@ static environment variables_cmd_core(parser & p, bool is_axiom, binder_info con
         scope1.emplace(p);
     parser::param_universe_scope scope2(p);
     expr type = p.parse_expr();
+    parse_close_binder_info(p, bi);
     level_param_names ls = to_level_param_names(collect_univ_params(type));
     type = p.elaborate(type, ls);
     environment env = p.env();
     for (auto id : ids)
-        env = declare_var(p, env, id, ls, type, is_axiom, bi, pos);
+        env = declare_var(p, env, id, ls, type, true, bi, pos);
     return env;
 }
-environment variables_cmd(parser & p) {
+
-    return variables_cmd_core(p, false, binder_info());
-}
-environment implicit_variables_cmd(parser & p) {
-    check_in_section(p);
-    return variables_cmd_core(p, false, mk_implicit_binder_info());
-}
-environment cast_variables_cmd(parser & p) {
-    check_in_section(p);
-    return variables_cmd_core(p, false, mk_cast_binder_info());
-}
 
 void register_decl_cmds(cmd_table & r) {
     add_cmd(r, cmd_info("universe",     "declare a global universe level", universe_cmd));
     add_cmd(r, cmd_info("variable",     "declare a new parameter", variable_cmd));
-    add_cmd(r, cmd_info("{variable}",   "declare a new implict parameter", implicit_variable_cmd));
-    add_cmd(r, cmd_info("[variable]",   "declare a new cast parameter", cast_variable_cmd));
     add_cmd(r, cmd_info("axiom",        "declare a new axiom", axiom_cmd));
-    add_cmd(r, cmd_info("{axiom}",      "declare a new implicit axiom", implicit_axiom_cmd));
     add_cmd(r, cmd_info("definition",   "add new definition", definition_cmd));
     add_cmd(r, cmd_info("abbreviation", "add new abbreviation (aka transparent definition)", abbreviation_cmd));
     add_cmd(r, cmd_info("theorem",      "add new theorem", theorem_cmd));
     add_cmd(r, cmd_info("variables",    "declare new parameters", variables_cmd));
-    add_cmd(r, cmd_info("{variables}",  "declare new implict parameters", implicit_variables_cmd));
-    add_cmd(r, cmd_info("[variables]",  "declare new cast parameters", cast_variables_cmd));
 }
 }

src/frontends/lean/token_table.cpp

@@ -61,8 +61,8 @@ token_table init_token_table() {
          {"(*", 0}, {"(--", 0}, {"proof", 0}, {"qed", 0},
          {"+", g_plus_prec}, {g_cup, g_cup_prec}, {"->", g_arrow_prec}, {nullptr, 0}};
 
-    char const * commands[] = {"theorem", "axiom", "variable", "definition", "{axiom}", "{variable}", "[variable]",
+    char const * commands[] = {"theorem", "axiom", "variable", "definition",
-                               "variables", "{variables}", "[variables]", "[private]", "[inline]", "[fact]", "abbreviation",
+                               "variables", "[private]", "[inline]", "[fact]", "abbreviation",
                                "evaluate", "check", "print", "end", "namespace", "section", "import",
                                "abbreviation", "inductive", "record", "structure", "module", "universe",
                                "precedence", "infixl", "infixr", "infix", "postfix", "notation", "exit", "set_option",
@@ -75,9 +75,6 @@ token_table init_token_table() {
     std::pair<char const *, char const *> cmd_aliases[] =
         {{"parameter", "variable"}, {"parameters", "variables"}, {"lemma", "theorem"},
          {"hypothesis", "axiom"}, {"conjecture", "axiom"}, {"corollary", "theorem"},
-         {"{parameter}", "{variable}"}, {"{parameters}", "{variables}"},
-         {"[parameter]", "[variable]"}, {"[parameters]", "[variables]"},
-         {"{hypothesis}", "{axiom}"}, {"{conjecture}", "{axiom}"},
          {nullptr, nullptr}};
 
     auto it = builtin;

tests/lean/run/t11.lean

@@ -3,9 +3,9 @@ parameters a b c : A
 parameter f : A → A → A
 check f a b
 section
-  parameters   A B : Type
+  parameters A B : Type
-  {parameters} C D : Type
+  parameters {C D : Type}
-  [parameters] e d : A
+  parameters [e d : A]
   check A
   check B
   definition g (a : A) (b : B) (c : C) : A := e

tests/lean/t4.lean

@@ -17,7 +17,7 @@ section
    variable A  : Type
    variable B  : Bool
    hypothesis H : B
-   {parameter} C : Type
+   parameter {C : Type}
    check B -> B
    check A → A
    check C

tests/lean/t6.lean

@@ -1,6 +1,6 @@
 definition Bool : Type.{1} := Type.{0}
 section
-  {parameter} A : Type  -- Mark A as implicit parameter
+  parameter {A : Type}  -- Mark A as implicit parameter
   parameter   R : A → A → Bool
   definition  id (a : A) : A := a
   definition  refl : Bool := forall (a : A), R a a
@@ -9,4 +9,3 @@ end
 check id.{2}
 check refl.{1}
 check symm.{1}
-

tests/lean/t7.lean

@@ -1,7 +1,7 @@
 definition Bool : Type.{1} := Type.{0}
 variable and : Bool → Bool → Bool
 section
-  {parameter} A : Type  -- Mark A as implicit parameter
+  parameter {A : Type}  -- Mark A as implicit parameter
   parameter   R : A → A → Bool
   parameter   B : Type
   definition  id (a : A) : A := a