feat(frontends/lean): remove 'using' from structure instance command

library/algebra/group.lean

@@ -252,24 +252,22 @@ section group
   iff.intro eq_mul_inv_of_mul_eq mul_eq_of_eq_mul_inv
 
   definition group.to_left_cancel_semigroup [instance] [coercion] : left_cancel_semigroup A :=
-  ⦃ left_cancel_semigroup,
+  ⦃ left_cancel_semigroup, s,
     mul_left_cancel := take a b c,
       assume H : a * b = a * c,
       calc
         b = a⁻¹ * (a * b) : inv_mul_cancel_left
           ... = a⁻¹ * (a * c) : H
-          ... = c : inv_mul_cancel_left,
-    using s ⦄
+          ... = c : inv_mul_cancel_left⦄
 
   definition group.to_right_cancel_semigroup [instance] [coercion] : right_cancel_semigroup A :=
-  ⦃ right_cancel_semigroup,
+  ⦃ right_cancel_semigroup, s,
     mul_right_cancel := take a b c,
       assume H : a * b = c * b,
       calc
         a = (a * b) * b⁻¹ : mul_inv_cancel_right
           ... = (c * b) * b⁻¹ : H
-          ... = c : mul_inv_cancel_right,
-    using s ⦄
+          ... = c : mul_inv_cancel_right⦄
 
 end group
 
@@ -382,25 +380,23 @@ section add_group
 
   definition add_group.to_left_cancel_semigroup [instance] [coercion] :
     add_left_cancel_semigroup A :=
-  ⦃ add_left_cancel_semigroup,
+  ⦃ add_left_cancel_semigroup, s,
     add_left_cancel := take a b c,
       assume H : a + b = a + c,
       calc
         b = -a + (a + b) : !neg_add_cancel_left⁻¹
           ... = -a + (a + c) : H
-          ... = c : neg_add_cancel_left,
-    using s ⦄
+          ... = c : neg_add_cancel_left ⦄
 
   definition add_group.to_add_right_cancel_semigroup [instance] [coercion] :
     add_right_cancel_semigroup A :=
-  ⦃ add_right_cancel_semigroup,
+  ⦃ add_right_cancel_semigroup, s,
     add_right_cancel := take a b c,
       assume H : a + b = c + b,
       calc
         a = (a + b) + -b : !add_neg_cancel_right⁻¹
           ... = (c + b) + -b : H
-          ... = c : add_neg_cancel_right,
-    using s ⦄
+          ... = c : add_neg_cancel_right ⦄
 
   /- sub -/
 

library/algebra/ordered_group.lean

@@ -201,7 +201,7 @@ structure ordered_comm_group [class] (A : Type) extends add_comm_group A, order_
 
 definition ordered_comm_group.to_ordered_cancel_comm_monoid [instance] [coercion]
     [s : ordered_comm_group A] : ordered_cancel_comm_monoid A :=
-⦃ ordered_cancel_comm_monoid,
+⦃ ordered_cancel_comm_monoid, s,
   add_left_cancel  := @add.left_cancel _ _,
   add_right_cancel := @add.right_cancel _ _,
   le_of_add_le_add_left :=
@@ -210,8 +210,7 @@ definition ordered_comm_group.to_ordered_cancel_comm_monoid [instance] [coercion
       assume H : a + b ≤ a + c,
       have H' : -a + (a + b) ≤ -a + (a + c), from ordered_comm_group.add_le_add_left _ _ H _,
       !neg_add_cancel_left ▸ !neg_add_cancel_left ▸ H'
-    qed,
-  using s ⦄
+    qed ⦄
 
 section
   variables [s : ordered_comm_group A] (a b c d e : A)

library/algebra/ordered_ring.lean

@@ -146,7 +146,7 @@ structure ordered_ring [class] (A : Type) extends ring A, ordered_comm_group A :
 
 definition ordered_ring.to_ordered_semiring [instance] [coercion] [s : ordered_ring A] :
   ordered_semiring A :=
-⦃ ordered_semiring,
+⦃ ordered_semiring, s,
   mul_zero := mul_zero,
   zero_mul := zero_mul,
   add_left_cancel  := @add.left_cancel A _,
@@ -187,8 +187,8 @@ definition ordered_ring.to_ordered_semiring [instance] [coercion] [s : ordered_r
       have H1 : 0 < b - a, from iff.elim_right !sub_pos_iff_lt Hab,
       have H2 : 0 < (b - a) * c, from ordered_ring.mul_pos _ _ H1 Hc,
       iff.mp !sub_pos_iff_lt (!mul_sub_right_distrib ▸ H2)
-    qed,
-  using s ⦄
+    qed
+⦄
 
 section
   variable [s : ordered_ring A]
@@ -243,7 +243,7 @@ structure linear_ordered_ring [class] (A : Type) extends ordered_ring A, linear_
 definition linear_ordered_ring.to_linear_ordered_semiring [instance] [coercion]
     [s : linear_ordered_ring A] :
   linear_ordered_semiring A :=
-⦃ linear_ordered_semiring,
+⦃ linear_ordered_semiring, s,
   mul_zero                   := mul_zero,
   zero_mul                   := zero_mul,
   add_left_cancel            := @add.left_cancel A _,
@@ -253,8 +253,8 @@ definition linear_ordered_ring.to_linear_ordered_semiring [instance] [coercion]
   mul_le_mul_of_nonneg_right := @mul_le_mul_of_nonneg_right A _,
   mul_lt_mul_of_pos_left     := @mul_lt_mul_of_pos_left A _,
   mul_lt_mul_of_pos_right    := @mul_lt_mul_of_pos_right A _,
-  le_total                   := linear_ordered_ring.le_total,
-  using s ⦄
+  le_total                   := linear_ordered_ring.le_total
+⦄
 
 structure linear_ordered_comm_ring [class] (A : Type) extends linear_ordered_ring A, comm_monoid A
 
@@ -262,7 +262,7 @@ structure linear_ordered_comm_ring [class] (A : Type) extends linear_ordered_rin
 definition linear_ordered_comm_ring.to_integral_domain [instance] [coercion]
     [s: linear_ordered_comm_ring A] :
   integral_domain A :=
-⦃ integral_domain,
+⦃ integral_domain, s,
   eq_zero_or_eq_zero_of_mul_eq_zero := take a b,
     assume H : a * b = 0,
     show a = 0 ∨ b = 0, from
@@ -277,8 +277,8 @@ definition linear_ordered_comm_ring.to_integral_domain [instance] [coercion]
           lt.by_cases
             (assume Hb : 0 < b, absurd (H ▸ mul_neg_of_neg_of_pos Ha Hb) (lt.irrefl 0))
             (assume Hb : 0 = b, or.inr (Hb⁻¹))
-            (assume Hb : 0 > b, absurd (H ▸ mul_pos_of_neg_of_neg Ha Hb) (lt.irrefl 0))),
-  using s ⦄
+            (assume Hb : 0 > b, absurd (H ▸ mul_pos_of_neg_of_neg Ha Hb) (lt.irrefl 0)))
+⦄
 
 section
   variable [s : linear_ordered_ring A]

library/algebra/ring.lean

@@ -153,7 +153,7 @@ end comm_semiring
 structure ring [class] (A : Type) extends add_comm_group A, monoid A, distrib A, zero_ne_one_class A
 
 definition ring.to_semiring [instance] [coercion] [s : ring A] : semiring A :=
-⦃ semiring,
+⦃ semiring, s,
   mul_zero := take a,
     have H : a * 0 + 0 = a * 0 + a * 0, from
       calc
@@ -167,8 +167,7 @@ definition ring.to_semiring [instance] [coercion] [s : ring A] : semiring A :=
         0 * a + 0 = 0 * a : add_zero
           ... = (0 + 0) * a : {(add_zero 0)⁻¹}
           ... = 0 * a + 0 * a : ring.right_distrib,
-    show 0 * a = 0, from  (add.left_cancel H)⁻¹,
-  using s ⦄
+    show 0 * a = 0, from  (add.left_cancel H)⁻¹ ⦄
 
 section
   variables [s : ring A] (a b c d e : A)
@@ -223,10 +222,9 @@ end
 structure comm_ring [class] (A : Type) extends ring A, comm_semigroup A
 
 definition comm_ring.to_comm_semiring [instance] [coercion] [s : comm_ring A] : comm_semiring A :=
-⦃ comm_semiring,
+⦃ comm_semiring, s,
   mul_zero := mul_zero,
-  zero_mul := zero_mul,
-  using s ⦄
+  zero_mul := zero_mul ⦄
 
 section
   variables [s : comm_ring A] (a b c d e : A)

src/frontends/lean/parser.cpp

@@ -1247,12 +1247,12 @@ expr parser::parse_expr(unsigned rbp) {
     return left;
 }
 
-pair<optional<name>, expr> parser::parse_qualified_expr(unsigned rbp) {
+pair<optional<name>, expr> parser::parse_id_tk_expr(name const & tk, unsigned rbp) {
     if (curr_is_identifier()) {
         auto id_pos = pos();
         name id = get_name_val();
         next();
-        if (curr_is_token(get_colon_tk())) {
+        if (curr_is_token(tk)) {
             next();
             return mk_pair(optional<name>(id), parse_expr(rbp));
         } else {
@@ -1267,6 +1267,14 @@ pair<optional<name>, expr> parser::parse_qualified_expr(unsigned rbp) {
     }
 }
 
+pair<optional<name>, expr> parser::parse_qualified_expr(unsigned rbp) {
+    return parse_id_tk_expr(get_colon_tk(), rbp);
+}
+
+pair<optional<name>, expr> parser::parse_optional_assignment(unsigned rbp) {
+    return parse_id_tk_expr(get_assign_tk(), rbp);
+}
+
 expr parser::parse_scoped_expr(unsigned num_ps, expr const * ps, local_environment const & lenv, unsigned rbp) {
     local_scope scope(*this);
     m_env = lenv;

src/frontends/lean/parser.h

@@ -193,6 +193,8 @@ class parser {
                                     bool allow_empty, unsigned rbp);
     bool parse_local_notation_decl(buffer<notation_entry> * entries);
 
+    pair<optional<name>, expr> parse_id_tk_expr(name const & tk, unsigned rbp);
+
     friend environment section_cmd(parser & p);
     friend environment context_cmd(parser & p);
     friend environment namespace_cmd(parser & p);
@@ -352,12 +354,15 @@ public:
     expr id_to_expr(name const & id, pos_info const & p);
 
     expr parse_expr(unsigned rbp = 0);
-    /**
-       \brief Parse an (optionally) qualified expression.
-       If the input is of the form <id> : <expr>, then return the pair (some(id), expr).
-       Otherwise, parse the next expression and return (none, expr).
+    /** \brief Parse an (optionally) qualified expression.
+        If the input is of the form <id> : <expr>, then return the pair (some(id), expr).
+        Otherwise, parse the next expression and return (none, expr).
     */
     pair<optional<name>, expr> parse_qualified_expr(unsigned rbp = 0);
+    /** \brief If the input is of the form <id> := <expr>, then return the pair (some(id), expr).
+        Otherwise, parse the next expression and return (none, expr).
+    */
+    pair<optional<name>, expr> parse_optional_assignment(unsigned rbp = 0);
 
     expr parse_led(expr left);
     expr parse_scoped_expr(unsigned num_params, expr const * ps, local_environment const & lenv, unsigned rbp = 0);

src/frontends/lean/structure_cmd.cpp

@@ -985,13 +985,12 @@ static expr parse_struct_expr_core(parser & p, pos_info const & pos, bool curly_
     buffer<expr> using_exprs;
     while (p.curr_is_token(get_comma_tk())) {
         p.next();
-        if (p.curr_is_token(get_using_tk())) {
-            p.next();
-            using_exprs.push_back(p.parse_expr());
+        pair<optional<name>, expr> id_e = p.parse_optional_assignment();
+        if (id_e.first) {
+            field_names.push_back(*id_e.first);
+            field_values.push_back(id_e.second);
         } else {
-            field_names.push_back(p.check_atomic_id_next("invalid structure instance, identifier expected"));
-            p.check_token_next(get_assign_tk(), "invalid structure instance, ':=' expected");
-            field_values.push_back(p.parse_expr());
+            using_exprs.push_back(id_e.second);
         }
     }
     if (curly_bar)

tests/lean/run/struct_inst_exprs.lean

@@ -11,7 +11,7 @@ definition s2 := ⦃ test, a := 3, b := 10 ⦄
 
 eval s2
 
-definition s3 := {| test, a := 20, using s2 |}
+definition s3 := {| test, a := 20, s2 |}
 
 eval s3
 

tests/lean/run/struct_inst_exprs2.lean

@@ -12,7 +12,7 @@ structure s3 (A : Type) extends s1 A, s2 A :=
 
 definition v1 : s1 nat := {| s1, x := 10, y := 10, h := rfl |}
 definition v2 : s2 nat := {| s2, mul := nat.add, one := zero |}
-definition v3 : s3 nat := {| s3, mul_one := add_zero, using v1, using v2 |}
+definition v3 : s3 nat := {| s3, mul_one := add_zero, v1, v2 |}
 
 example : s3.x v3 = 10 := rfl
 example : s3.y v3 = 10 := rfl