fix(frontends/lean): calc configuration commands, add check_constant_next auxiliary method

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

src/frontends/lean/builtin_cmds.cpp

@@ -272,16 +272,12 @@ environment opaque_hint_cmd(parser & p) {
                 p.next();
                 env = set_main_module_opaque_defs(env, hiding);
             } else {
-                auto pos = p.pos();
-                name id  = p.check_id_next("invalid 'opaque_hint', identifier expected");
-                found    = true;
-                expr e   = p.id_to_expr(id, pos);
-                if (!is_constant(e))
-                    throw parser_error(sstream() << "'" << id << "' is not a constant", pos);
+                name c  = p.check_constant_next("invalid 'opaque_hint', constant expected");
+                found   = true;
                 if (hiding)
-                    env = hide_definition(env, const_name(e));
+                    env = hide_definition(env, c);
                 else
-                    env = expose_definition(env, const_name(e));
+                    env = expose_definition(env, c);
             }
         }
         p.next();

src/frontends/lean/calc.cpp

@@ -154,17 +154,17 @@ static void calc_trans_reader(deserializer & d, module_idx, shared_environment &
 register_module_object_reader_fn g_calc_trans_reader(g_calc_trans_key, calc_trans_reader);
 
 environment calc_subst_cmd(parser & p) {
-    name id = p.check_id_next("invalid 'calc_subst' command, identifier expected");
+    name id = p.check_constant_next("invalid 'calc_subst' command, constant expected");
     return add_calc_subst(p.env(), id);
 }
 
 environment calc_refl_cmd(parser & p) {
-    name id = p.check_id_next("invalid 'calc_refl' command, identifier expected");
+    name id = p.check_constant_next("invalid 'calc_refl' command, constant expected");
     return add_calc_refl(p.env(), id);
 }
 
 environment calc_trans_cmd(parser & p) {
-    name id = p.check_id_next("invalid 'calc_trans' command, identifier expected");
+    name id = p.check_constant_next("invalid 'calc_trans' command, constant expected");
     return add_calc_trans(p.env(), id);
 }
 

src/frontends/lean/class.cpp

@@ -94,12 +94,8 @@ environment add_instance_cmd(parser & p) {
     environment env = p.env();
     while (p.curr_is_identifier()) {
         found    = true;
-        auto pos = p.pos();
-        name c   = p.get_name_val();
-        p.next();
-        expr e   = p.id_to_expr(c, pos);
-        if (!is_constant(e)) throw parser_error(sstream() << "invalid 'class instance' declaration, '" << c << "' is not a constant", pos);
-        env = add_instance(env, const_name(e));
+        name c   = p.check_constant_next("invalid 'class instance' declaration, constant expected");
+        env = add_instance(env, c);
     }
     if (!found)
         throw parser_error("invalid 'class instance' declaration, at least one identifier expected", p.pos());

src/frontends/lean/parser.cpp

@@ -856,6 +856,15 @@ expr parser::id_to_expr(name const & id, pos_info const & p) {
     }
 }
 
+name parser::check_constant_next(char const * msg) {
+    auto p  = pos();
+    name id = check_id_next(msg);
+    expr e  = id_to_expr(id, p);
+    if (!is_constant(e))
+        throw parser_error(msg, p);
+    return const_name(e);
+}
+
 expr parser::parse_id() {
     auto p  = pos();
     name id = get_name_val();

src/frontends/lean/parser.h

@@ -190,9 +190,10 @@ public:
     void check_token_next(name const & tk, char const * msg);
     /** \brief Check if the current token is an identifier, if it is return it and move to next token, otherwise throw an exception. */
     name check_id_next(char const * msg);
-    /** \brief Check if the current token is an atomic identifier, if it is return it and move to next token,
-        otherwise throw an exception. */
+    /** \brief Check if the current token is an atomic identifier, if it is, return it and move to next token, otherwise throw an exception. */
     name check_atomic_id_next(char const * msg);
+    /** \brief Check if the current token is a constant, if it is, return it and move to next token, otherwise throw an exception. */
+    name check_constant_next(char const * msg);
 
     mpq const & get_num_val() const { return m_scanner.get_num_val(); }
     name const & get_name_val() const { return m_scanner.get_name_val(); }

src/frontends/lean/tactic_hint.cpp

@@ -92,15 +92,12 @@ list<tactic_hint_entry> get_tactic_hints(environment const & env) {
 }
 
 expr parse_tactic_name(parser & p) {
-    auto pos     = p.pos();
-    name id      = p.check_id_next("invalid tactic name, identifier expected");
-    expr pre_tac = p.id_to_expr(id, pos);
-    if (!is_constant(pre_tac))
-        throw parser_error(sstream() << "invalid tactic name, '" << id << "' is not a constant", pos);
-    expr pre_tac_type = p.env().get(const_name(pre_tac)).get_type();
+    auto pos = p.pos();
+    name pre_tac = p.check_constant_next("invalid tactic name, constant expected");
+    expr pre_tac_type = p.env().get(pre_tac).get_type();
     if (!is_constant(pre_tac_type) || const_name(pre_tac_type) != name({"tactic", "tactic"}))
-        throw parser_error(sstream() << "invalid tactic name, '" << id << "' is not a tactic", pos);
-    return pre_tac;
+        throw parser_error(sstream() << "invalid tactic name, '" << pre_tac << "' is not a tactic", pos);
+    return mk_constant(pre_tac);
 }
 
 static name g_lbracket("[");

tests/lean/run/calc.lean

@@ -0,0 +1,17 @@
+import standard
+using num
+
+namespace foo
+  variable le : num → num → Bool
+  axiom le_trans {a b c : num} : le a b → le b c → le a c
+  calc_trans le_trans
+  infix `≤`:50 := le
+end
+
+namespace foo
+  theorem T {a b c d : num} : a ≤ b → b ≤ c → c ≤ d → a ≤ d
+  := assume H1 H2 H3,
+     calc a  ≤ b : H1
+         ... ≤ c : H2
+         ... ≤ d : H3
+end