should support recursive mlhs decomposition, e.g. (a,b),c = [1,2],3

src/codegen.c

@@ -953,6 +953,18 @@ gen_assignment(codegen_scope *s, node *tree, int sp, int val)
     }
     break;
 
+  case NODE_MASGN:
+    gen_vmassignment(s, tree->car, sp, val);
+    break;
+
+    push();
+    gen_call(s, tree, attrsym(s, sym(tree->cdr->car)), sp, NOVAL);
+    pop();
+    if (val) {
+      genop_peep(s, MKOP_AB(OP_MOVE, cursp(), sp), val);
+    }
+    break;
+
   default:
 #ifdef ENABLE_STDIO
     printf("unknown lhs %d\n", type);
@@ -1006,7 +1018,7 @@ gen_vmassignment(codegen_scope *s, node *tree, int rhs, int val)
       }
     }
   }
-  else {
+  else if (val) {
     pop();
   }
 }

src/parse.y

@@ -1468,7 +1468,7 @@ mlhs            : mlhs_basic
 mlhs_inner      : mlhs_basic
                 | tLPAREN mlhs_inner rparen
                     {
-                      $$ = list1($2);
+                      $$ = $2;
                     }
                 ;
 
@@ -1517,7 +1517,7 @@ mlhs_basic      : mlhs_list
 mlhs_item       : mlhs_node
                 | tLPAREN mlhs_inner rparen
                     {
-                      $$ = $2;
+                      $$ = new_masgn(p, $2, NULL);
                     }
                 ;