Merge branch 'master' into built_in_floor_ceil

flake.lock

@@ -2,16 +2,16 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1637636156,
+        "lastModified": 1638279546,
-        "narHash": "sha256-E2ym4Vcpqu9JYoQDXJZR48gVD+LPPbaCoYveIk7Xu3Y=",
+        "narHash": "sha256-1KCwN7twjp1dBdp0jPgVdYFztDkCR8+roo0B34J9oBY=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "b026e1cf87a108dd06fe521f224fdc72fd0b013d",
+        "rev": "96b4157790fc96e70d6e6c115e3f34bba7be490f",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
-        "ref": "release-21.11",
+        "ref": "nixos-21.11",
         "repo": "nixpkgs",
         "type": "github"
       }

flake.nix

@@ -1,7 +1,7 @@
 {
   description = "The third-generation ARTIQ compiler";
 
-  inputs.nixpkgs.url = github:NixOS/nixpkgs/release-21.11;
+  inputs.nixpkgs.url = github:NixOS/nixpkgs/nixos-21.11;
 
   outputs = { self, nixpkgs }:
     let

nac3artiq/demo/min_artiq.py

@@ -9,13 +9,17 @@ import nac3artiq
 __all__ = ["KernelInvariant", "extern", "kernel", "portable", "nac3",
            "ms", "us", "ns",
            "print_int32", "print_int64",
-           "Core", "TTLOut", "parallel", "sequential"]
+           "Core", "TTLOut", "parallel", "sequential", "virtual"]
 
 
 T = TypeVar('T')
+
 class KernelInvariant(Generic[T]):
     pass
 
+# The virtual class must exist before nac3artiq.NAC3 is created.
+class virtual(Generic[T]):
+    pass
 
 import device_db
 core_arguments = device_db.device_db["core"]["arguments"]

nac3artiq/src/lib.rs

@@ -55,6 +55,10 @@ pub struct PrimitivePythonId {
     bool: u64,
     list: u64,
     tuple: u64,
+    typevar: u64,
+    none: u64,
+    generic_alias: (u64, u64),
+    virtual_id: u64,
 }
 
 // TopLevelComposer is unsendable as it holds the unification table, which is
@@ -96,10 +100,13 @@ impl Nac3 {
                     let val = id_fn.call1((member.get_item(1)?,))?.extract()?;
                     name_to_pyid.insert(key.into(), val);
                 }
+                let typings = PyModule::import(py, "typing")?;
                 let helper = PythonHelper {
                     id_fn: builtins.getattr("id").unwrap().to_object(py),
                     len_fn: builtins.getattr("len").unwrap().to_object(py),
                     type_fn: builtins.getattr("type").unwrap().to_object(py),
+                    origin_ty_fn: typings.getattr("get_origin").unwrap().to_object(py),
+                    args_ty_fn: typings.getattr("get_args").unwrap().to_object(py),
                 };
                 Ok((
                     module.getattr("__name__")?.extract()?,
@@ -284,7 +291,42 @@ impl Nac3 {
         let builtins_mod = PyModule::import(py, "builtins").unwrap();
         let id_fn = builtins_mod.getattr("id").unwrap();
         let numpy_mod = PyModule::import(py, "numpy").unwrap();
+        let typing_mod = PyModule::import(py, "typing").unwrap();
+        let types_mod = PyModule::import(py, "types").unwrap();
         let primitive_ids = PrimitivePythonId {
+            virtual_id: id_fn
+                .call1((builtins_mod
+                    .getattr("globals")
+                    .unwrap()
+                    .call0()
+                    .unwrap()
+                    .get_item("virtual")
+                    .unwrap(),
+                )).unwrap()
+                .extract()
+                .unwrap(),
+            generic_alias: (
+                id_fn
+                    .call1((typing_mod.getattr("_GenericAlias").unwrap(),))
+                    .unwrap()
+                    .extract()
+                    .unwrap(),
+                id_fn
+                    .call1((types_mod.getattr("GenericAlias").unwrap(),))
+                    .unwrap()
+                    .extract()
+                    .unwrap(),
+            ),
+            none: id_fn
+                .call1((builtins_mod.getattr("None").unwrap(),))
+                .unwrap()
+                .extract()
+                .unwrap(),
+            typevar: id_fn
+                .call1((typing_mod.getattr("TypeVar").unwrap(),))
+                .unwrap()
+                .extract()
+                .unwrap(),
             int: id_fn
                 .call1((builtins_mod.getattr("int").unwrap(),))
                 .unwrap()
@@ -403,10 +445,13 @@ impl Nac3 {
         };
         let mut synthesized = parse_program(&synthesized).unwrap();
         let builtins = PyModule::import(py, "builtins")?;
+        let typings = PyModule::import(py, "typing")?;
         let helper = PythonHelper {
             id_fn: builtins.getattr("id").unwrap().to_object(py),
             len_fn: builtins.getattr("len").unwrap().to_object(py),
             type_fn: builtins.getattr("type").unwrap().to_object(py),
+            origin_ty_fn: typings.getattr("get_origin").unwrap().to_object(py),
+            args_ty_fn: typings.getattr("get_args").unwrap().to_object(py),
         };
         let resolver = Arc::new(Resolver(Arc::new(InnerResolver {
             id_to_type: self.builtins_ty.clone().into(),

nac3artiq/src/symbol_resolver.rs

@@ -43,6 +43,8 @@ pub struct PythonHelper {
     pub type_fn: PyObject,
     pub len_fn: PyObject,
     pub id_fn: PyObject,
+    pub origin_ty_fn: PyObject,
+    pub args_ty_fn: PyObject,
 }
 
 struct PythonValue {
@@ -133,47 +135,46 @@ impl InnerResolver {
         }))
     }
 
-    fn get_obj_type(
+    // handle python objects that represent types themselves
+    // primitives and class types should be themselves, use `ty_id` to check,
+    // TypeVars and GenericAlias(`A[int, bool]`) should use `ty_ty_id` to check
+    // the `bool` value returned indicates whether they are instantiated or not
+    fn get_pyty_obj_type(
         &self,
         py: Python,
-        obj: &PyAny,
+        pyty: &PyAny,
         unifier: &mut Unifier,
         defs: &[Arc<RwLock<TopLevelDef>>],
         primitives: &PrimitiveStore,
-    ) -> PyResult<Option<Type>> {
+    ) -> PyResult<Result<(Type, bool), String>> {
         let ty_id: u64 = self
             .helper
             .id_fn
-            .call1(py, (self.helper.type_fn.call1(py, (obj,))?,))?
+            .call1(py, (pyty,))?
+            .extract(py)?;
+        let ty_ty_id: u64 = self
+            .helper
+            .id_fn
+            .call1(py, (self.helper.type_fn.call1(py, (pyty,))?,))?
             .extract(py)?;
 
         if ty_id == self.primitive_ids.int || ty_id == self.primitive_ids.int32 {
-            Ok(Some(primitives.int32))
+            Ok(Ok((primitives.int32, true)))
         } else if ty_id == self.primitive_ids.int64 {
-            Ok(Some(primitives.int64))
+            Ok(Ok((primitives.int64, true)))
         } else if ty_id == self.primitive_ids.bool {
-            Ok(Some(primitives.bool))
+            Ok(Ok((primitives.bool, true)))
         } else if ty_id == self.primitive_ids.float {
-            Ok(Some(primitives.float))
+            Ok(Ok((primitives.float, true)))
         } else if ty_id == self.primitive_ids.list {
-            let len: usize = self.helper.len_fn.call1(py, (obj,))?.extract(py)?;
+            // do not handle type var param and concrete check here
-            if len == 0 {
+            let var = unifier.get_fresh_var().0;
-                let var = unifier.get_fresh_var().0;
+            let list = unifier.add_ty(TypeEnum::TList { ty: var });
-                let list = unifier.add_ty(TypeEnum::TList { ty: var });
+            Ok(Ok((list, false)))
-                Ok(Some(list))
-            } else {
-                let ty = self.get_list_elem_type(py, obj, len, unifier, defs, primitives)?;
-                Ok(ty.map(|ty| unifier.add_ty(TypeEnum::TList { ty })))
-            }
         } else if ty_id == self.primitive_ids.tuple {
-            let elements: &PyTuple = obj.cast_as()?;
+            // do not handle type var param and concrete check here
-            let types: Result<Option<Vec<_>>, _> = elements
+            Ok(Ok((unifier.add_ty(TypeEnum::TTuple { ty: vec![] }), false)))
-                .iter()
+        } else if let Some(def_id) = self.pyid_to_def.read().get(&ty_id).cloned() {
-                .map(|elem| self.get_obj_type(py, elem, unifier, defs, primitives))
-                .collect();
-            let types = types?;
-            Ok(types.map(|types| unifier.add_ty(TypeEnum::TTuple { ty: types })))
-        } else if let Some(def_id) = self.pyid_to_def.read().get(&ty_id) {
             let def = defs[def_id.0].read();
             if let TopLevelDef::Class {
                 object_id,
@@ -183,54 +184,274 @@ impl InnerResolver {
                 ..
             } = &*def
             {
-                let var_map: HashMap<_, _> = type_vars
+                // do not handle type var param and concrete check here, and no subst
-                    .iter()
+                Ok(Ok({
-                    .map(|var| {
+                    let ty = TypeEnum::TObj {
-                        (
+                        obj_id: *object_id,
-                            if let TypeEnum::TVar { id, .. } = &*unifier.get_ty(*var) {
+                        params: RefCell::new({
-                                *id
+                            type_vars
-                            } else {
+                                .iter()
-                                unreachable!()
+                                .map(|x| {
-                            },
+                                    if let TypeEnum::TVar { id, .. } = &*unifier.get_ty(*x) {
-                            unifier.get_fresh_var().0,
+                                        (*id, *x)
-                        )
+                                    } else {
-                    })
+                                        unreachable!()
-                    .collect();
+                                    }
-                let mut fields_ty = HashMap::new();
+                                }).collect()
-                for method in methods.iter() {
+                        }),
-                    fields_ty.insert(method.0, (method.1, false));
+                        fields: RefCell::new({
-                }
+                            let mut res = methods
-                for field in fields.iter() {
+                                .iter()
-                    let name: String = field.0.into();
+                                .map(|(iden, ty, _)| (*iden, (*ty, false)))
-                    let field_data = obj.getattr(&name)?;
+                                .collect::<HashMap<_, _>>();
-                    let ty = self
+                            res.extend(fields.clone().into_iter().map(|x| (x.0, (x.1, x.2))));
-                        .get_obj_type(py, field_data, unifier, defs, primitives)?
+                            res
-                        .unwrap_or(primitives.none);
+                        })
-                    let field_ty = unifier.subst(field.1, &var_map).unwrap_or(field.1);
+                    };
-                    if unifier.unify(ty, field_ty).is_err() {
+                    // here also false, later instantiation use python object to check compatible
-                        // field type mismatch
+                    (unifier.add_ty(ty), false)
-                        return Ok(None);
+                }))
+            } else {
+                // only object is supported, functions are not supported
+                unreachable!("function type is not supported, should not be queried")
+            }
+        } else if ty_ty_id == self.primitive_ids.typevar {
+            let constraint_types = {
+                let constraints = pyty.getattr("__constraints__").unwrap();
+                let mut result: Vec<Type> = vec![];
+                for i in 0.. {
+                    if let Ok(constr) = constraints.get_item(i) {
+                        result.push({
+                            match self.get_pyty_obj_type(py, constr, unifier, defs, primitives)? {
+                                Ok((ty, _)) => {
+                                    if unifier.is_concrete(ty, &[]) {
+                                        ty
+                                    } else {
+                                        return Ok(Err(format!(
+                                            "the {}th constraint of TypeVar `{}` is not concrete",
+                                            i + 1,
+                                            pyty.getattr("__name__")?.extract::<String>()?
+                                        )))
+                                    }
+                                },
+                                Err(err) => return Ok(Err(err))
+                            }
+                        })
+                    } else {
+                        break;
+                    }
+                }
+                result
+            };
+            let res = unifier.get_fresh_var_with_range(&constraint_types).0;
+            Ok(Ok((res, true)))
+        } else if ty_ty_id == self.primitive_ids.generic_alias.0 || ty_ty_id == self.primitive_ids.generic_alias.1 {
+            let origin = self.helper.origin_ty_fn.call1(py, (pyty,))?;
+            let args = self.helper.args_ty_fn.call1(py, (pyty,))?;
+            let args: &PyTuple = args.cast_as(py)?;
+            let origin_ty = match self.get_pyty_obj_type(py, origin.as_ref(py), unifier, defs, primitives)? {
+                Ok((ty, false)) => ty,
+                Ok((_, true)) => return Ok(Err("instantiated type does not take type parameters".into())),
+                Err(err) => return Ok(Err(err))
+            };
+
+            match &*unifier.get_ty(origin_ty) {
+                TypeEnum::TList { .. } => {
+                    if args.len() == 1 {
+                        let ty = match self.get_pyty_obj_type(py, args.get_item(0), unifier, defs, primitives)? {
+                            Ok(ty) => ty,
+                            Err(err) => return Ok(Err(err))
+                        };
+                        if !unifier.is_concrete(ty.0, &[]) && !ty.1 {
+                            panic!("type list should take concrete parameters in type var ranges")
+                        }
+                        Ok(Ok((unifier.add_ty(TypeEnum::TList { ty: ty.0 }), true)))
+                    } else {
+                        return Ok(Err(format!("type list needs exactly 1 type parameters, found {}", args.len())))
+                    }
+                 },
+                TypeEnum::TTuple { .. } => {
+                    let args = match args
+                        .iter()
+                        .map(|x| self.get_pyty_obj_type(py, x, unifier, defs, primitives))
+                        .collect::<Result<Vec<_>, _>>()?
+                        .into_iter()
+                        .collect::<Result<Vec<_>, _>>() {
+                            Ok(args) if !args.is_empty() => args
+                                .into_iter()
+                                .map(|(x, check)| if !unifier.is_concrete(x, &[]) && !check {
+                                        panic!("type tuple should take concrete parameters in type var ranges")
+                                    } else {
+                                        x
+                                    }
+                                )
+                                .collect::<Vec<_>>(),
+                            Err(err) => return Ok(Err(err)),
+                            _ => return Ok(Err("tuple type needs at least 1 type parameters".to_string()))
+                        };
+                    Ok(Ok((unifier.add_ty(TypeEnum::TTuple { ty: args }), true)))
+                },
+                TypeEnum::TObj { params, obj_id, .. } => {
+                    let subst = {
+                        let params = &*params.borrow();
+                        if params.len() != args.len() {
+                            return Ok(Err(format!(
+                                "for class #{}, expect {} type parameters, got {}.",
+                                obj_id.0,
+                                params.len(),
+                                args.len(),
+                            )))
+                        }
+                        let args = match args
+                            .iter()
+                            .map(|x| self.get_pyty_obj_type(py, x, unifier, defs, primitives))
+                            .collect::<Result<Vec<_>, _>>()?
+                            .into_iter()
+                            .collect::<Result<Vec<_>, _>>() {
+                                Ok(args) => args
+                                .into_iter()
+                                .map(|(x, check)| if !unifier.is_concrete(x, &[]) && !check {
+                                        panic!("type class should take concrete parameters in type var ranges")
+                                    } else {
+                                        x
+                                    }
+                                )
+                                .collect::<Vec<_>>(),
+                                Err(err) => return Ok(Err(err)),
+                            };
+                        params
+                            .iter()
+                            .zip(args.iter())
+                            .map(|((id, _), ty)| (*id, *ty))
+                            .collect::<HashMap<_, _>>()
+                    };
+                    Ok(Ok((unifier.subst(origin_ty, &subst).unwrap_or(origin_ty), true)))
+                },
+                TypeEnum::TVirtual { .. } => {
+                    if args.len() == 1 {
+                        let ty = match self.get_pyty_obj_type(py, args.get_item(0), unifier, defs, primitives)? {
+                            Ok(ty) => ty,
+                            Err(err) => return Ok(Err(err))
+                        };
+                        if !unifier.is_concrete(ty.0, &[]) && !ty.1 {
+                            panic!("virtual class should take concrete parameters in type var ranges")
+                        }
+                        Ok(Ok((unifier.add_ty(TypeEnum::TVirtual { ty: ty.0 }), true)))
+                    } else {
+                        return Ok(Err(format!("virtual class needs exactly 1 type parameters, found {}", args.len())))
+                    }
+                }
+                _ => unimplemented!()
+            }
+        } else if ty_id == self.primitive_ids.virtual_id {
+            Ok(Ok(({
+                let ty = TypeEnum::TVirtual { ty: unifier.get_fresh_var().0 };
+                unifier.add_ty(ty)
+            }, false)))
+        } else {
+            Ok(Err("unknown type".into()))
+        }
+    }
+
+    fn get_obj_type(
+        &self,
+        py: Python,
+        obj: &PyAny,
+        unifier: &mut Unifier,
+        defs: &[Arc<RwLock<TopLevelDef>>],
+        primitives: &PrimitiveStore,
+    ) -> PyResult<Option<Type>> {
+        let ty = self.helper.type_fn.call1(py, (obj,)).unwrap();
+        let (extracted_ty, inst_check) = match self.get_pyty_obj_type(
+            py,
+            {
+                if [self.primitive_ids.typevar,
+                    self.primitive_ids.generic_alias.0,
+                    self.primitive_ids.generic_alias.1
+                ].contains(&self.helper.id_fn.call1(py, (ty.clone(),))?.extract::<u64>(py)?) {
+                    obj
+                } else {
+                    ty.as_ref(py)
+                }
+            },
+            unifier,
+            defs,
+            primitives
+        )? {
+            Ok(s) => s,
+            Err(_) => return Ok(None)
+        };
+        return match (&*unifier.get_ty(extracted_ty), inst_check) {
+            // do the instantiation for these three types
+            (TypeEnum::TList { ty }, false) => {
+                let len: usize = self.helper.len_fn.call1(py, (obj,))?.extract(py)?;
+                if len == 0 {
+                    assert!(matches!(
+                        &*unifier.get_ty(extracted_ty),
+                        TypeEnum::TVar { meta: nac3core::typecheck::typedef::TypeVarMeta::Generic, range, .. }
+                            if range.borrow().is_empty()
+                    ));
+                    Ok(Some(extracted_ty))
+                } else {
+                    let actual_ty = self
+                        .get_list_elem_type(py, obj, len, unifier, defs, primitives)?;
+                    if let Some(actual_ty) = actual_ty {
+                        unifier.unify(*ty, actual_ty).unwrap();
+                        Ok(Some(extracted_ty))
+                    } else {
+                        Ok(None)
+                    }
+                }
+            }
+            (TypeEnum::TTuple { .. }, false) => {
+                let elements: &PyTuple = obj.cast_as()?;
+                let types: Result<Option<Vec<_>>, _> = elements
+                    .iter()
+                    .map(|elem| self.get_obj_type(py, elem, unifier, defs, primitives))
+                    .collect();
+                let types = types?;
+                Ok(types.map(|types| unifier.add_ty(TypeEnum::TTuple { ty: types })))
+            }
+            (TypeEnum::TObj { params, fields, .. }, false) => {
+                let var_map = params
+                    .borrow()
+                    .iter()
+                    .map(|(id_var, ty)| {
+                        if let TypeEnum::TVar { id, range, .. } = &*unifier.get_ty(*ty) {
+                            assert_eq!(*id, *id_var);
+                            (*id, unifier.get_fresh_var_with_range(&range.borrow()).0)
+                        } else {
+                            unreachable!()
+                        }
+                    })
+                    .collect::<HashMap<_, _>>();
+                // loop through non-function fields of the class to get the instantiated value
+                for field in fields.borrow().iter() {
+                    let name: String = (*field.0).into();
+                    if let TypeEnum::TFunc( .. ) = &*unifier.get_ty(field.1.0) {
+                        continue;
+                    } else {
+                        let field_data = obj.getattr(&name)?;
+                        let ty = self
+                            .get_obj_type(py, field_data, unifier, defs, primitives)?
+                            .unwrap_or(primitives.none);
+                        let field_ty = unifier.subst(field.1.0, &var_map).unwrap_or(field.1.0);
+                        if unifier.unify(ty, field_ty).is_err() {
+                            // field type mismatch
+                            return Ok(None);
+                        }
                     }
-                    fields_ty.insert(field.0, (ty, field.2));
                 }
                 for (_, ty) in var_map.iter() {
                     // must be concrete type
                     if !unifier.is_concrete(*ty, &[]) {
-                        return Ok(None);
+                        return Ok(None)
                     }
                 }
-                Ok(Some(unifier.add_ty(TypeEnum::TObj {
+                return Ok(Some(unifier.subst(extracted_ty, &var_map).unwrap_or(extracted_ty)));
-                    obj_id: *object_id,
-                    fields: RefCell::new(fields_ty),
-                    params: RefCell::new(var_map),
-                })))
-            } else {
-                // only object is supported, functions are not supported
-                Ok(None)
             }
-        } else {
+            _ => Ok(Some(extracted_ty))
-            Ok(None)
+        };
-        }
     }
 
     fn get_obj_value<'ctx, 'a>(
@@ -620,4 +841,4 @@ impl SymbolResolver for Resolver {
             result
         })
     }
-}
+}

nac3core/src/symbol_resolver.rs

@@ -138,159 +138,165 @@ pub fn parse_type_annotation<T>(
     let list_id = ids[6];
     let tuple_id = ids[7];
 
-    match &expr.node {
+    let name_handling = |id: &StrRef, unifier: &mut Unifier| {
-        Name { id, .. } => {
+        if *id == int32_id {
-            if *id == int32_id {
+            Ok(primitives.int32)
-                Ok(primitives.int32)
+        } else if *id == int64_id {
-            } else if *id == int64_id {
+            Ok(primitives.int64)
-                Ok(primitives.int64)
+        } else if *id == float_id {
-            } else if *id == float_id {
+            Ok(primitives.float)
-                Ok(primitives.float)
+        } else if *id == bool_id {
-            } else if *id == bool_id {
+            Ok(primitives.bool)
-                Ok(primitives.bool)
+        } else if *id == none_id {
-            } else if *id == none_id {
+            Ok(primitives.none)
-                Ok(primitives.none)
+        } else {
-            } else {
+            let obj_id = resolver.get_identifier_def(*id);
-                let obj_id = resolver.get_identifier_def(*id);
+            if let Some(obj_id) = obj_id {
-                if let Some(obj_id) = obj_id {
+                let def = top_level_defs[obj_id.0].read();
-                    let def = top_level_defs[obj_id.0].read();
+                if let TopLevelDef::Class { fields, methods, type_vars, .. } = &*def {
-                    if let TopLevelDef::Class { fields, methods, type_vars, .. } = &*def {
+                    if !type_vars.is_empty() {
-                        if !type_vars.is_empty() {
+                        return Err(format!(
-                            return Err(format!(
+                            "Unexpected number of type parameters: expected {} but got 0",
-                                "Unexpected number of type parameters: expected {} but got 0",
+                            type_vars.len()
-                                type_vars.len()
+                        ));
-                            ));
-                        }
-                        let fields = RefCell::new(
-                            chain(
-                                fields.iter().map(|(k, v, m)| (*k, (*v, *m))),
-                                methods.iter().map(|(k, v, _)| (*k, (*v, false))),
-                            )
-                            .collect(),
-                        );
-                        Ok(unifier.add_ty(TypeEnum::TObj {
-                            obj_id,
-                            fields,
-                            params: Default::default(),
-                        }))
-                    } else {
-                        Err("Cannot use function name as type".into())
                     }
+                    let fields = RefCell::new(
+                        chain(
+                            fields.iter().map(|(k, v, m)| (*k, (*v, *m))),
+                            methods.iter().map(|(k, v, _)| (*k, (*v, false))),
+                        )
+                        .collect(),
+                    );
+                    Ok(unifier.add_ty(TypeEnum::TObj {
+                        obj_id,
+                        fields,
+                        params: Default::default(),
+                    }))
                 } else {
-                    // it could be a type variable
+                    Err("Cannot use function name as type".into())
-                    let ty = resolver
+                }
-                        .get_symbol_type(unifier, top_level_defs, primitives, *id)
+            } else {
-                        .ok_or_else(|| "unknown type variable name".to_owned())?;
+                // it could be a type variable
-                    if let TypeEnum::TVar { .. } = &*unifier.get_ty(ty) {
+                let ty = resolver
-                        Ok(ty)
+                    .get_symbol_type(unifier, top_level_defs, primitives, *id)
-                    } else {
+                    .ok_or_else(|| "unknown type variable name".to_owned())?;
-                        Err(format!("Unknown type annotation {}", id))
+                if let TypeEnum::TVar { .. } = &*unifier.get_ty(ty) {
-                    }
+                    Ok(ty)
+                } else {
+                    Err(format!("Unknown type annotation {}", id))
                 }
             }
         }
-        Subscript { value, slice, .. } => {
+    };
-            if let Name { id, .. } = &value.node {
+
-                if *id == virtual_id {
+    let subscript_name_handle = |id: &StrRef, slice: &Expr<T>, unifier: &mut Unifier| {
-                    let ty = parse_type_annotation(
+        if *id == virtual_id {
-                        resolver,
+            let ty = parse_type_annotation(
-                        top_level_defs,
+                resolver,
-                        unifier,
+                top_level_defs,
-                        primitives,
+                unifier,
-                        slice,
+                primitives,
-                    )?;
+                slice,
-                    Ok(unifier.add_ty(TypeEnum::TVirtual { ty }))
+            )?;
-                } else if *id == list_id {
+            Ok(unifier.add_ty(TypeEnum::TVirtual { ty }))
-                    let ty = parse_type_annotation(
+        } else if *id == list_id {
-                        resolver,
+            let ty = parse_type_annotation(
-                        top_level_defs,
+                resolver,
-                        unifier,
+                top_level_defs,
-                        primitives,
+                unifier,
-                        slice,
+                primitives,
-                    )?;
+                slice,
-                    Ok(unifier.add_ty(TypeEnum::TList { ty }))
+            )?;
-                } else if *id == tuple_id {
+            Ok(unifier.add_ty(TypeEnum::TList { ty }))
-                    if let Tuple { elts, .. } = &slice.node {
+        } else if *id == tuple_id {
-                        let ty = elts
+            if let Tuple { elts, .. } = &slice.node {
-                            .iter()
+                let ty = elts
-                            .map(|elt| {
+                    .iter()
-                                parse_type_annotation(
+                    .map(|elt| {
-                                    resolver,
+                        parse_type_annotation(
-                                    top_level_defs,
-                                    unifier,
-                                    primitives,
-                                    elt,
-                                )
-                            })
-                            .collect::<Result<Vec<_>, _>>()?;
-                        Ok(unifier.add_ty(TypeEnum::TTuple { ty }))
-                    } else {
-                        Err("Expected multiple elements for tuple".into())
-                    }
-                } else {
-                    let types = if let Tuple { elts, .. } = &slice.node {
-                        elts.iter()
-                            .map(|v| {
-                                parse_type_annotation(
-                                    resolver,
-                                    top_level_defs,
-                                    unifier,
-                                    primitives,
-                                    v,
-                                )
-                            })
-                            .collect::<Result<Vec<_>, _>>()?
-                    } else {
-                        vec![parse_type_annotation(
                             resolver,
                             top_level_defs,
                             unifier,
                             primitives,
-                            slice,
+                            elt,
-                        )?]
+                        )
-                    };
+                    })
+                    .collect::<Result<Vec<_>, _>>()?;
+                Ok(unifier.add_ty(TypeEnum::TTuple { ty }))
+            } else {
+                Err("Expected multiple elements for tuple".into())
+            }
+        } else {
+            let types = if let Tuple { elts, .. } = &slice.node {
+                elts.iter()
+                    .map(|v| {
+                        parse_type_annotation(
+                            resolver,
+                            top_level_defs,
+                            unifier,
+                            primitives,
+                            v,
+                        )
+                    })
+                    .collect::<Result<Vec<_>, _>>()?
+            } else {
+                vec![parse_type_annotation(
+                    resolver,
+                    top_level_defs,
+                    unifier,
+                    primitives,
+                    slice,
+                )?]
+            };
 
-                    let obj_id = resolver
+            let obj_id = resolver
-                        .get_identifier_def(*id)
+                .get_identifier_def(*id)
-                        .ok_or_else(|| format!("Unknown type annotation {}", id))?;
+                .ok_or_else(|| format!("Unknown type annotation {}", id))?;
-                    let def = top_level_defs[obj_id.0].read();
+            let def = top_level_defs[obj_id.0].read();
-                    if let TopLevelDef::Class { fields, methods, type_vars, .. } = &*def {
+            if let TopLevelDef::Class { fields, methods, type_vars, .. } = &*def {
-                        if types.len() != type_vars.len() {
+                if types.len() != type_vars.len() {
-                            return Err(format!(
+                    return Err(format!(
-                                "Unexpected number of type parameters: expected {} but got {}",
+                        "Unexpected number of type parameters: expected {} but got {}",
-                                type_vars.len(),
+                        type_vars.len(),
-                                types.len()
+                        types.len()
-                            ));
+                    ));
-                        }
-                        let mut subst = HashMap::new();
-                        for (var, ty) in izip!(type_vars.iter(), types.iter()) {
-                            let id = if let TypeEnum::TVar { id, .. } = &*unifier.get_ty(*var) {
-                                *id
-                            } else {
-                                unreachable!()
-                            };
-                            subst.insert(id, *ty);
-                        }
-                        let mut fields = fields
-                            .iter()
-                            .map(|(attr, ty, is_mutable)| {
-                                let ty = unifier.subst(*ty, &subst).unwrap_or(*ty);
-                                (*attr, (ty, *is_mutable))
-                            })
-                            .collect::<HashMap<_, _>>();
-                        fields.extend(methods.iter().map(|(attr, ty, _)| {
-                            let ty = unifier.subst(*ty, &subst).unwrap_or(*ty);
-                            (*attr, (ty, false))
-                        }));
-                        Ok(unifier.add_ty(TypeEnum::TObj {
-                            obj_id,
-                            fields: fields.into(),
-                            params: subst.into(),
-                        }))
-                    } else {
-                        Err("Cannot use function name as type".into())
-                    }
                 }
+                let mut subst = HashMap::new();
+                for (var, ty) in izip!(type_vars.iter(), types.iter()) {
+                    let id = if let TypeEnum::TVar { id, .. } = &*unifier.get_ty(*var) {
+                        *id
+                    } else {
+                        unreachable!()
+                    };
+                    subst.insert(id, *ty);
+                }
+                let mut fields = fields
+                    .iter()
+                    .map(|(attr, ty, is_mutable)| {
+                        let ty = unifier.subst(*ty, &subst).unwrap_or(*ty);
+                        (*attr, (ty, *is_mutable))
+                    })
+                    .collect::<HashMap<_, _>>();
+                fields.extend(methods.iter().map(|(attr, ty, _)| {
+                    let ty = unifier.subst(*ty, &subst).unwrap_or(*ty);
+                    (*attr, (ty, false))
+                }));
+                Ok(unifier.add_ty(TypeEnum::TObj {
+                    obj_id,
+                    fields: fields.into(),
+                    params: subst.into(),
+                }))
+            } else {
+                Err("Cannot use function name as type".into())
+            }
+        }
+    };
+
+    match &expr.node {
+        Name { id, .. } => name_handling(id, unifier),
+        Subscript { value, slice, .. } => {
+            if let Name { id, .. } = &value.node {
+                subscript_name_handle(id, slice, unifier)
             } else {
                 Err("unsupported type expression".into())
             }

nac3core/src/toplevel/builtins.rs

@@ -379,7 +379,14 @@ pub fn get_built_ins(primitives: &mut (PrimitiveStore, Unifier)) -> BuiltinInfo
                     let arg = args[0].1;
                     if ctx.unifier.unioned(arg_ty, boolean) {
                         Some(arg)
-                    } else if ctx.unifier.unioned(arg_ty, int32) || ctx.unifier.unioned(arg_ty, int64) {
+                    } else if ctx.unifier.unioned(arg_ty, int32) {
+                        Some(ctx.builder.build_int_compare(
+                            IntPredicate::NE,
+                            ctx.ctx.i32_type().const_zero(),
+                            arg.into_int_value(),
+                            "bool",
+                        ).into())
+                    } else if ctx.unifier.unioned(arg_ty, int64) {
                         Some(ctx.builder.build_int_compare(
                             IntPredicate::NE,
                             ctx.ctx.i64_type().const_zero(),

nac3core/src/toplevel/composer.rs

@@ -1,10 +1,8 @@
 use std::cell::RefCell;
 
 use nac3parser::ast::fold::Fold;
-use inkwell::{FloatPredicate, IntPredicate};
 
 use crate::{
-    symbol_resolver::SymbolValue,
     typecheck::type_inferencer::{FunctionData, Inferencer},
     codegen::expr::get_subst_key,
 };
@@ -131,7 +129,7 @@ impl TopLevelComposer {
         }
     }
 
-    fn extract_def_list(&self) -> Vec<Arc<RwLock<TopLevelDef>>> {
+    pub fn extract_def_list(&self) -> Vec<Arc<RwLock<TopLevelDef>>> {
         self.definition_ast_list.iter().map(|(def, ..)| def.clone()).collect_vec()
     }
 

nac3core/src/toplevel/mod.rs

@@ -24,8 +24,8 @@ pub struct DefinitionId(pub usize);
 
 pub mod composer;
 pub mod helper;
-mod type_annotation;
 pub mod builtins;
+pub mod type_annotation;
 use composer::*;
 use type_annotation::*;
 #[cfg(test)]

nac3core/src/toplevel/type_annotation.rs

@@ -1,7 +1,6 @@
 use std::cell::RefCell;
 
 use crate::typecheck::typedef::TypeVarMeta;
-
 use super::*;
 
 #[derive(Clone, Debug)]
@@ -49,54 +48,121 @@ pub fn parse_ast_to_type_annotation_kinds<T>(
     primitives: &PrimitiveStore,
     expr: &ast::Expr<T>,
     // the key stores the type_var of this topleveldef::class, we only need this field here
-    mut locked: HashMap<DefinitionId, Vec<Type>>,
+    locked: HashMap<DefinitionId, Vec<Type>>,
 ) -> Result<TypeAnnotation, String> {
-    match &expr.node {
+    let name_handle = |id: &StrRef, unifier: &mut Unifier, locked: HashMap<DefinitionId, Vec<Type>>| {
-        ast::ExprKind::Name { id, .. } => {
+        if id == &"int32".into() {
-            if id == &"int32".into() {
+            Ok(TypeAnnotation::Primitive(primitives.int32))
-                Ok(TypeAnnotation::Primitive(primitives.int32))
+        } else if id == &"int64".into() {
-            } else if id == &"int64".into() {
+            Ok(TypeAnnotation::Primitive(primitives.int64))
-                Ok(TypeAnnotation::Primitive(primitives.int64))
+        } else if id == &"float".into() {
-            } else if id == &"float".into() {
+            Ok(TypeAnnotation::Primitive(primitives.float))
-                Ok(TypeAnnotation::Primitive(primitives.float))
+        } else if id == &"bool".into() {
-            } else if id == &"bool".into() {
+            Ok(TypeAnnotation::Primitive(primitives.bool))
-                Ok(TypeAnnotation::Primitive(primitives.bool))
+        } else if id == &"None".into() {
-            } else if id == &"None".into() {
+            Ok(TypeAnnotation::Primitive(primitives.none))
-                Ok(TypeAnnotation::Primitive(primitives.none))
+        } else if id == &"str".into() {
-            } else if id == &"str".into() {
+            Ok(TypeAnnotation::Primitive(primitives.str))
-                Ok(TypeAnnotation::Primitive(primitives.str))
+        } else if let Some(obj_id) = resolver.get_identifier_def(*id) {
-            } else if let Some(obj_id) = resolver.get_identifier_def(*id) {
+            let type_vars = {
-                let type_vars = {
+                let def_read = top_level_defs[obj_id.0].try_read();
-                    let def_read = top_level_defs[obj_id.0].try_read();
+                if let Some(def_read) = def_read {
-                    if let Some(def_read) = def_read {
+                    if let TopLevelDef::Class { type_vars, .. } = &*def_read {
-                        if let TopLevelDef::Class { type_vars, .. } = &*def_read {
+                        type_vars.clone()
-                            type_vars.clone()
-                        } else {
-                            return Err("function cannot be used as a type".into());
-                        }
                     } else {
-                        locked.get(&obj_id).unwrap().clone()
+                        return Err("function cannot be used as a type".into());
                     }
-                };
-                // check param number here
-                if !type_vars.is_empty() {
-                    return Err(format!(
-                        "expect {} type variable parameter but got 0",
-                        type_vars.len()
-                    ));
-                }
-                Ok(TypeAnnotation::CustomClass { id: obj_id, params: vec![] })
-            } else if let Some(ty) = resolver.get_symbol_type(unifier, top_level_defs, primitives, *id) {
-                if let TypeEnum::TVar { .. } = unifier.get_ty(ty).as_ref() {
-                    Ok(TypeAnnotation::TypeVar(ty))
                 } else {
-                    Err("not a type variable identifier".into())
+                    locked.get(&obj_id).unwrap().clone()
+                }
+            };
+            // check param number here
+            if !type_vars.is_empty() {
+                return Err(format!(
+                    "expect {} type variable parameter but got 0",
+                    type_vars.len()
+                ));
+            }
+            Ok(TypeAnnotation::CustomClass { id: obj_id, params: vec![] })
+        } else if let Some(ty) = resolver.get_symbol_type(unifier, top_level_defs, primitives, *id) {
+            if let TypeEnum::TVar { .. } = unifier.get_ty(ty).as_ref() {
+                Ok(TypeAnnotation::TypeVar(ty))
+            } else {
+                Err("not a type variable identifier".into())
+            }
+        } else {
+            Err("name cannot be parsed as a type annotation".into())
+        }
+    };
+
+    let class_name_handle =
+        |id: &StrRef, slice: &ast::Expr<T>, unifier: &mut Unifier, mut locked: HashMap<DefinitionId, Vec<Type>>| {
+        if vec!["virtual".into(), "Generic".into(), "list".into(), "tuple".into()]
+                .contains(id)
+            {
+                return Err("keywords cannot be class name".into());
+            }
+        let obj_id = resolver
+            .get_identifier_def(*id)
+            .ok_or_else(|| "unknown class name".to_string())?;
+        let type_vars = {
+            let def_read = top_level_defs[obj_id.0].try_read();
+            if let Some(def_read) = def_read {
+                if let TopLevelDef::Class { type_vars, .. } = &*def_read {
+                    type_vars.clone()
+                } else {
+                    unreachable!("must be class here")
                 }
             } else {
-                Err("name cannot be parsed as a type annotation".into())
+                locked.get(&obj_id).unwrap().clone()
             }
-        }
+        };
-
+        // we do not check whether the application of type variables are compatible here
+        let param_type_infos = {
+            let params_ast = if let ast::ExprKind::Tuple { elts, .. } = &slice.node {
+                elts.iter().collect_vec()
+            } else {
+                vec![slice]
+            };
+            if type_vars.len() != params_ast.len() {
+                return Err(format!(
+                    "expect {} type parameters but got {}",
+                    type_vars.len(),
+                    params_ast.len()
+                ));
+            }
+            let result = params_ast
+                .into_iter()
+                .map(|x| {
+                    parse_ast_to_type_annotation_kinds(
+                        resolver,
+                        top_level_defs,
+                        unifier,
+                        primitives,
+                        x,
+                        {
+                            locked.insert(obj_id, type_vars.clone());
+                            locked.clone()
+                        },
+                    )
+                })
+                .collect::<Result<Vec<_>, _>>()?;
+            // make sure the result do not contain any type vars
+            let no_type_var = result
+                .iter()
+                .all(|x| get_type_var_contained_in_type_annotation(x).is_empty());
+            if no_type_var {
+                result
+            } else {
+                return Err("application of type vars to generic class \
+                is not currently supported"
+                    .into());
+            }
+        };
+        Ok(TypeAnnotation::CustomClass { id: obj_id, params: param_type_infos })
+    };
+    match &expr.node {
+        ast::ExprKind::Name { id, .. } => name_handle(id, unifier, locked),
         // virtual
         ast::ExprKind::Subscript { value, slice, .. }
             if {
@@ -163,71 +229,7 @@ pub fn parse_ast_to_type_annotation_kinds<T>(
         // custom class
         ast::ExprKind::Subscript { value, slice, .. } => {
             if let ast::ExprKind::Name { id, .. } = &value.node {
-                if vec!["virtual".into(), "Generic".into(), "list".into(), "tuple".into()]
+                class_name_handle(id, slice, unifier, locked)
-                    .contains(id)
-                {
-                    return Err("keywords cannot be class name".into());
-                }
-                let obj_id = resolver
-                    .get_identifier_def(*id)
-                    .ok_or_else(|| "unknown class name".to_string())?;
-                let type_vars = {
-                    let def_read = top_level_defs[obj_id.0].try_read();
-                    if let Some(def_read) = def_read {
-                        if let TopLevelDef::Class { type_vars, .. } = &*def_read {
-                            type_vars.clone()
-                        } else {
-                            unreachable!("must be class here")
-                        }
-                    } else {
-                        locked.get(&obj_id).unwrap().clone()
-                    }
-                };
-                // we do not check whether the application of type variables are compatible here
-                let param_type_infos = {
-                    let params_ast = if let ast::ExprKind::Tuple { elts, .. } = &slice.node {
-                        elts.iter().collect_vec()
-                    } else {
-                        vec![slice.as_ref()]
-                    };
-                    if type_vars.len() != params_ast.len() {
-                        return Err(format!(
-                            "expect {} type parameters but got {}",
-                            type_vars.len(),
-                            params_ast.len()
-                        ));
-                    }
-                    let result = params_ast
-                        .into_iter()
-                        .map(|x| {
-                            parse_ast_to_type_annotation_kinds(
-                                resolver,
-                                top_level_defs,
-                                unifier,
-                                primitives,
-                                x,
-                                {
-                                    locked.insert(obj_id, type_vars.clone());
-                                    locked.clone()
-                                },
-                            )
-                        })
-                        .collect::<Result<Vec<_>, _>>()?;
-
-                    // make sure the result do not contain any type vars
-                    let no_type_var = result
-                        .iter()
-                        .all(|x| get_type_var_contained_in_type_annotation(x).is_empty());
-                    if no_type_var {
-                        result
-                    } else {
-                        return Err("application of type vars to generic class \
-                        is not currently supported"
-                            .into());
-                    }
-                };
-
-                Ok(TypeAnnotation::CustomClass { id: obj_id, params: param_type_infos })
             } else {
                 Err("unsupported expression type for class name".into())
             }
@@ -370,13 +372,7 @@ pub fn get_type_from_type_annotation_kinds(
 /// But note that here we do not make a duplication of `T`, `V`, we direclty
 /// use them as they are in the TopLevelDef::Class since those in the
 /// TopLevelDef::Class.type_vars will be substitute later when seeing applications/instantiations
-/// the Type of their fields and methods will also be subst when application/instantiation \
+/// the Type of their fields and methods will also be subst when application/instantiation
-/// \
-/// Note this implicit self type is different with seeing `A[T, V]` explicitly outside
-/// the class def ast body, where it is a new instantiation of the generic class `A`,
-/// but equivalent to seeing `A[T, V]` inside the class def body ast, where although we
-/// create copies of `T` and `V`, we will find them out as occured type vars in the analyze_class()
-/// and unify them with the class generic `T`, `V`
 pub fn make_self_type_annotation(type_vars: &[Type], object_id: DefinitionId) -> TypeAnnotation {
     TypeAnnotation::CustomClass {
         id: object_id,

nac3core/src/typecheck/function_check.rs

@@ -167,7 +167,6 @@ impl<'a> Inferencer<'a> {
             }
             ExprKind::Constant { .. } => {}
             _ => {
-                println!("{:?}", expr.node);
                 unimplemented!()
             }
         }

nac3core/src/typecheck/typedef/mod.rs

@@ -855,7 +855,6 @@ impl Unifier {
                 }
             }
             _ => {
-                println!("{}", ty.get_type_name());
                 unreachable!("{} not expected", ty.get_type_name())
             }
         }

nac3standalone/src/main.rs

@@ -3,8 +3,9 @@ use inkwell::{
     targets::*,
     OptimizationLevel,
 };
-use nac3core::typecheck::type_inferencer::PrimitiveStore;
+use nac3core::typecheck::{type_inferencer::PrimitiveStore, typedef::{Type, Unifier}};
 use nac3parser::{ast::{Expr, ExprKind, StmtKind}, parser};
+use parking_lot::RwLock;
 use std::{borrow::Borrow, env};
 use std::fs;
 use std::{collections::HashMap, path::Path, sync::Arc, time::SystemTime};
@@ -15,7 +16,11 @@ use nac3core::{
         WorkerRegistry,
     },
     symbol_resolver::SymbolResolver,
-    toplevel::{composer::TopLevelComposer, TopLevelDef, helper::parse_parameter_default_value},
+    toplevel::{
+        composer::TopLevelComposer,
+        TopLevelDef, helper::parse_parameter_default_value,
+        type_annotation::*,
+    },
     typecheck::typedef::FunSignature,
 };
 
@@ -68,25 +73,84 @@ fn main() {
 
     for stmt in parser_result.into_iter() {
         if let StmtKind::Assign { targets, value, .. } = &stmt.node {
+            fn handle_typevar_definition(
+                var: &Expr,
+                resolver: &(dyn SymbolResolver + Send + Sync),
+                def_list: &[Arc<RwLock<TopLevelDef>>],
+                unifier: &mut Unifier,
+                primitives: &PrimitiveStore,
+            ) -> Result<Type, String> {
+                if let ExprKind::Call { func, args, .. } = &var.node {
+                    if matches!(&func.node, ExprKind::Name { id, .. } if id == &"TypeVar".into()) {
+                        let constraints = args
+                            .iter()
+                            .skip(1)
+                            .map(|x| -> Result<Type, String> {
+                                let ty = parse_ast_to_type_annotation_kinds(
+                                    resolver,
+                                    def_list,
+                                    unifier,
+                                    primitives,
+                                    x,
+                                    Default::default(),
+                                )?;
+                                get_type_from_type_annotation_kinds(def_list, unifier, primitives, &ty)
+                            })
+                            .collect::<Result<Vec<_>, _>>()?;
+                        Ok(unifier.get_fresh_var_with_range(&constraints).0)
+                    } else {
+                        Err(format!("expression {:?} cannot be handled as a TypeVar in global scope", var))
+                    }
+                } else {
+                    Err(format!("expression {:?} cannot be handled as a TypeVar in global scope", var))
+                }
+            }
+
             fn handle_assignment_pattern(
                 targets: &[Expr],
                 value: &Expr,
                 resolver: &(dyn SymbolResolver + Send + Sync),
                 internal_resolver: &ResolverInternal,
+                def_list: &[Arc<RwLock<TopLevelDef>>],
+                unifier: &mut Unifier,
+                primitives: &PrimitiveStore,
             ) -> Result<(), String> {
                 if targets.len() == 1 {
                     match &targets[0].node {
                         ExprKind::Name { id, .. } => {
-                            let val = parse_parameter_default_value(value.borrow(), resolver)?;
+                            if let Ok(var) = handle_typevar_definition(
-                            internal_resolver.add_module_global(*id, val);
+                                value.borrow(),
-                            Ok(())
+                                resolver,
+                                def_list,
+                                unifier,
+                                primitives,
+                            ) {
+                                internal_resolver.add_id_type(*id, var);
+                                Ok(())
+                            } else if let Ok(val) = parse_parameter_default_value(value.borrow(), resolver) {
+                                internal_resolver.add_module_global(*id, val);
+                                Ok(())
+                            } else {
+                                Err(format!("fails to evaluate this expression `{:?}` as a constant or TypeVar at {}",
+                                    targets[0].node,
+                                    targets[0].location,
+                                ))
+                            }
                         }
                         ExprKind::List { elts, .. }
                         | ExprKind::Tuple { elts, .. } => {
-                            handle_assignment_pattern(elts, value, resolver, internal_resolver)?;
+                            handle_assignment_pattern(
+                                elts,
+                                value,
+                                resolver,
+                                internal_resolver,
+                                def_list,
+                                unifier,
+                                primitives
+                            )?;
                             Ok(())
                         }
-                        _ => unreachable!("cannot be assigned")
+                        _ => Err(format!("assignment to {:?} is not supported at {}", targets[0], targets[0].location))
                     }
                 } else {
                     match &value.node {
@@ -105,7 +169,10 @@ fn main() {
                                         std::slice::from_ref(tar),
                                         val,
                                         resolver,
-                                        internal_resolver
+                                        internal_resolver,
+                                        def_list,
+                                        unifier,
+                                        primitives
                                     )?;
                                 }
                                 Ok(())
@@ -115,7 +182,19 @@ fn main() {
                     }
                 }
             }
-            if let Err(err) = handle_assignment_pattern(targets, value, resolver.as_ref(), internal_resolver.as_ref()) {
+
+            let def_list = composer.extract_def_list();
+            let unifier = &mut composer.unifier;
+            let primitives = &composer.primitives_ty;
+            if let Err(err) = handle_assignment_pattern(
+                targets,
+                value,
+                resolver.as_ref(),
+                internal_resolver.as_ref(),
+                &def_list,
+                unifier,
+                primitives,
+            ) {
                 eprintln!("{}", err);
                 return;
             }