...

src/compiler.h

@@ -322,7 +322,6 @@ class Compiler {
             if (curr().type == TK("]")) break;
             EXPR();
             items.push_back(ctx()->s_expr.popx());
-            if(items.back()->is_starred()) SyntaxError();
             match_newlines_repl();
             if(items.size()==1 && match(TK("for"))){
                 _consume_comp<ListCompExpr>(std::move(items[0]));
@@ -351,12 +350,9 @@ class Compiler {
                 auto dict_item = make_expr<DictItemExpr>();
                 dict_item->key = ctx()->s_expr.popx();
                 dict_item->value = ctx()->s_expr.popx();
-                if(dict_item->key->is_starred()) SyntaxError();
-                if(dict_item->value->is_starred()) SyntaxError();
                 items.push_back(std::move(dict_item));
             }else{
                 items.push_back(ctx()->s_expr.popx());
-                if(items.back()->is_starred()) SyntaxError();
             }
             match_newlines_repl();
             if(items.size()==1 && match(TK("for"))){

src/expr.h

@@ -370,10 +370,16 @@ struct DictItemExpr: Expr{
     Expr_ value;
     std::string str() const override { return "DictItem()"; }
 
+    int star_level() const override { return value->star_level(); }
+
     void emit(CodeEmitContext* ctx) override {
-        value->emit(ctx);
-        key->emit(ctx);     // reverse order
-        ctx->emit(OP_BUILD_TUPLE, 2, line);
+        if(is_starred()){
+            value->emit(ctx);
+        }else{
+            value->emit(ctx);
+            key->emit(ctx);     // reverse order
+            ctx->emit(OP_BUILD_TUPLE, 2, line);
+        }
     }
 };
 
@@ -391,7 +397,11 @@ struct SequenceExpr: Expr{
 struct ListExpr: SequenceExpr{
     using SequenceExpr::SequenceExpr;
     std::string str() const override { return "List()"; }
-    Opcode opcode() const override { return OP_BUILD_LIST; }
+
+    Opcode opcode() const override {
+        for(auto& e: items) if(e->is_starred()) return OP_BUILD_LIST_UNPACK;
+        return OP_BUILD_LIST;
+    }
 
     bool is_json_object() const override { return true; }
 };
@@ -399,7 +409,10 @@ struct ListExpr: SequenceExpr{
 struct DictExpr: SequenceExpr{
     using SequenceExpr::SequenceExpr;
     std::string str() const override { return "Dict()"; }
-    Opcode opcode() const override { return OP_BUILD_DICT; }
+    Opcode opcode() const override {
+        for(auto& e: items) if(e->is_starred()) return OP_BUILD_DICT_UNPACK;
+        return OP_BUILD_DICT;
+    }
 
     bool is_json_object() const override { return true; }
 };
@@ -407,13 +420,19 @@ struct DictExpr: SequenceExpr{
 struct SetExpr: SequenceExpr{
     using SequenceExpr::SequenceExpr;
     std::string str() const override { return "Set()"; }
-    Opcode opcode() const override { return OP_BUILD_SET; }
+    Opcode opcode() const override {
+        for(auto& e: items) if(e->is_starred()) return OP_BUILD_SET_UNPACK;
+        return OP_BUILD_SET;
+    }
 };
 
 struct TupleExpr: SequenceExpr{
     using SequenceExpr::SequenceExpr;
     std::string str() const override { return "Tuple()"; }
-    Opcode opcode() const override { return OP_BUILD_TUPLE; }
+    Opcode opcode() const override {
+        for(auto& e: items) if(e->is_starred()) return OP_BUILD_TUPLE_UNPACK;
+        return OP_BUILD_TUPLE;
+    }
 
     bool emit_store(CodeEmitContext* ctx) override {
         // TOS is an iterable