Start work on exprs

typon/trans/tests/user_generics.py

@@ -23,4 +23,4 @@
 
 
 if __name__ == "__main__":
-    print(5)
+    print("abc")
\ No newline at end of file

typon/trans/transpiler/phases/emit_cpp/expr.py

+# coding: utf-8
+import ast
+from dataclasses import dataclass, field
+from typing import Iterable
+
+from transpiler.phases.emit_cpp.visitors import NodeVisitor, CoroutineMode, join
+from transpiler.phases.typing.scope import Scope
+
+
+
+# noinspection PyPep8Naming
+@dataclass
+class ExpressionVisitor(NodeVisitor):
+    scope: Scope
+    generator: CoroutineMode
+
+    def visit(self, node):
+        if False and type(node) in SYMBOLS:
+            yield SYMBOLS[type(node)]
+        else:
+            yield from NodeVisitor.visit(self, node)
+
+    def visit_Tuple(self, node: ast.Tuple) -> Iterable[str]:
+        yield "std::make_tuple("
+        yield from join(", ", map(self.visit, node.elts))
+        yield ")"
+
+    def visit_Constant(self, node: ast.Constant) -> Iterable[str]:
+        if isinstance(node.value, str):
+            # TODO: escape sequences
+            yield f"\"{repr(node.value)[1:-1]}\"_ps"
+        elif isinstance(node.value, bool):
+            yield str(node.value).lower()
+        elif isinstance(node.value, int):
+            # TODO: bigints
+            yield str(node.value)
+        elif isinstance(node.value, float):
+            yield repr(node.value)
+        elif isinstance(node.value, complex):
+            yield f"PyComplex({node.value.real}, {node.value.imag})"
+        elif node.value is None:
+            yield "PyNone"
+        else:
+            raise NotImplementedError(node, type(node))
+
+    def visit_Slice(self, node: ast.Slice) -> Iterable[str]:
+        yield "PySlice("
+        yield from join(", ", (self.visit(x or ast.Constant(value=None)) for x in (node.lower, node.upper, node.step)))
+        yield ")"
+
+    def visit_Name(self, node: ast.Name) -> Iterable[str]:
+        res = self.fix_name(node.id)
+        if self.scope.function and (decl := self.scope.get(res)) and decl.type is self.scope.function.obj_type:
+            if not self.scope.function.parent.function:
+                res = "(*this)"
+            #if decl.kind == VarKind.SELF:
+            #    res = "(*this)"
+            #elif decl.future and CoroutineMode.ASYNC in self.generator:
+            #    res = f"{res}.get()"
+            #    if decl.future == "future":
+            #        res = "co_await " + res
+        yield res
+
+    # def visit_Compare(self, node: ast.Compare) -> Iterable[str]:
+    #     def make_lnd(op1, op2):
+    #         return {
+    #             "lineno": op1.lineno,
+    #             "col_offset": op1.col_offset,
+    #             "end_lineno": op2.end_lineno,
+    #             "end_col_offset": op2.end_col_offset
+    #         }
+    #
+    #     operands = [node.left, *node.comparators]
+    #     with self.prec_ctx("&&"):
+    #         yield from self.visit_binary_operation(node.ops[0], operands[0], operands[1], make_lnd(operands[0], operands[1]))
+    #         for (left, right), op in zip(zip(operands[1:], operands[2:]), node.ops[1:]):
+    #             # TODO: cleaner code
+    #             yield " && "
+    #             yield from self.visit_binary_operation(op, left, right, make_lnd(left, right))
+
+    def visit_BoolOp(self, node: ast.BoolOp) -> Iterable[str]:
+        if len(node.values) == 1:
+            yield from self.visit(node.values[0])
+            return
+        cpp_op = {
+            ast.And: "&&",
+            ast.Or: "||"
+        }[type(node.op)]
+        with self.prec_ctx(cpp_op):
+            yield from self.visit_binary_operation(cpp_op, node.values[0], node.values[1], make_lnd(node.values[0], node.values[1]))
+            for left, right in zip(node.values[1:], node.values[2:]):
+                yield f" {cpp_op} "
+                yield from self.visit_binary_operation(cpp_op, left, right, make_lnd(left, right))
+
+    def visit_Call(self, node: ast.Call) -> Iterable[str]:
+        # TODO
+        # if getattr(node, "keywords", None):
+        #     raise NotImplementedError(node, "keywords")
+        if getattr(node, "starargs", None):
+            raise NotImplementedError(node, "varargs")
+        if getattr(node, "kwargs", None):
+            raise NotImplementedError(node, "kwargs")
+        func = node.func
+        if isinstance(func, ast.Attribute):
+            if sym := DUNDER_SYMBOLS.get(func.attr, None):
+                if len(node.args) == 1:
+                    yield from self.visit_binary_operation(sym, func.value, node.args[0], linenodata(node))
+                else:
+                    yield from self.visit_unary_operation(sym, func.value)
+                return
+        for name in ("fork", "future"):
+            if compare_ast(func, ast.parse(name, mode="eval").body):
+                assert len(node.args) == 1
+                arg = node.args[0]
+                assert isinstance(arg, ast.Lambda)
+                node.is_future = name
+                vis = self.reset()
+                vis.generator = CoroutineMode.SYNC
+                # todo: bad code
+                if CoroutineMode.ASYNC in self.generator:
+                    yield f"co_await typon::{name}("
+                    yield from vis.visit(arg.body)
+                    yield ")"
+                    return
+                elif CoroutineMode.FAKE in self.generator:
+                    yield from self.visit(arg.body)
+                return
+        if compare_ast(func, ast.parse('sync', mode="eval").body):
+            if CoroutineMode.ASYNC in self.generator:
+                yield "co_await typon::Sync()"
+            elif CoroutineMode.FAKE in self.generator:
+                yield from ()
+            return
+        # TODO: precedence needed?
+        if CoroutineMode.ASYNC in self.generator and node.is_await:
+            yield "("  # TODO: temporary
+            yield "co_await "
+            node.in_await = True
+        elif CoroutineMode.FAKE in self.generator:
+            func = ast.Attribute(value=func, attr="sync", ctx=ast.Load())
+        yield from self.prec("()").visit(func)
+        yield "("
+        yield from join(", ", map(self.reset().visit, node.args))
+        yield ")"
+        if CoroutineMode.ASYNC in self.generator and node.is_await:
+            yield ")"
+
+    def visit_Lambda(self, node: ast.Lambda) -> Iterable[str]:
+        yield "[]"
+        templ, args, _ = self.process_args(node.args)
+        yield templ
+        yield args
+        yield "{"
+        yield "return"
+        yield from self.reset().visit(node.body)
+        yield ";"
+        yield "}"
+
+    def visit_BinOp(self, node: ast.BinOp) -> Iterable[str]:
+        yield from self.visit_binary_operation(node.op, node.left, node.right, linenodata(node))
+
+    def visit_Compare(self, node: ast.Compare) -> Iterable[str]:
+        yield from self.visit_binary_operation(node.ops[0], node.left, node.comparators[0], linenodata(node))
+
+    def visit_binary_operation(self, op, left: ast.AST, right: ast.AST, lnd: dict) -> Iterable[str]:
+        # if type(op) == ast.In:
+        #     call = ast.Call(ast.Attribute(right, "__contains__", **lnd), [left], [], **lnd)
+        #     call.is_await = False
+        #     yield from self.visit_Call(call)
+        #     print(call.func.type)
+        #     return
+        if type(op) != str:
+            op = SYMBOLS[type(op)]
+        # TODO: handle precedence locally since only binops really need it
+        # we could just store the history of traversed nodes and check if the last one was a binop
+        prio = self.precedence and PRECEDENCE_LEVELS[self.precedence[-1]] < PRECEDENCE_LEVELS[op]
+        if prio:
+            yield "("
+        with self.prec_ctx(op):
+            yield from self.visit(left)
+            yield op
+            yield from self.visit(right)
+        if prio:
+            yield ")"
+
+    def visit_Attribute(self, node: ast.Attribute) -> Iterable[str]:
+        yield "dot"
+        yield "(("
+        yield from self.visit(node.value)
+        yield "), "
+        yield self.fix_name(node.attr)
+        yield ")"
+
+    def visit_List(self, node: ast.List) -> Iterable[str]:
+        if node.elts:
+            yield "typon::PyList{"
+            yield from join(", ", map(self.reset().visit, node.elts))
+            yield "}"
+        else:
+            yield from self.visit(node.type)
+            yield "{}"
+
+    def visit_Set(self, node: ast.Set) -> Iterable[str]:
+        if node.elts:
+            yield "typon::PySet{"
+            yield from join(", ", map(self.reset().visit, node.elts))
+            yield "}"
+        else:
+            yield from self.visit(node.type)
+            yield "{}"
+
+    def visit_Dict(self, node: ast.Dict) -> Iterable[str]:
+        def visit_item(key, value):
+            yield "std::pair {"
+            yield from self.reset().visit(key)
+            yield ", "
+            yield from self.reset().visit(value)
+            yield "}"
+
+        if node.keys:
+            yield from self.visit(node.type)
+            yield "{"
+            yield from join(", ", map(visit_item, node.keys, node.values))
+            yield "}"
+        else:
+            yield from self.visit(node.type)
+            yield "{}"
+
+    def visit_Subscript(self, node: ast.Subscript) -> Iterable[str]:
+        if isinstance(node.type, TypeType) and isinstance(node.type.type_object, MonomorphizedUserType):
+            yield node.type.type_object.name
+            return
+        yield from self.prec("[]").visit(node.value)
+        yield "["
+        yield from self.reset().visit(node.slice)
+        yield "]"
+
+    def visit_UnaryOp(self, node: ast.UnaryOp) -> Iterable[str]:
+        yield from self.visit_unary_operation(node.op, node.operand)
+
+    def visit_unary_operation(self, op, operand) -> Iterable[str]:
+        if type(op) != str:
+            op = SYMBOLS[type(op)]
+        yield op
+        yield from self.prec("unary").visit(operand)
+
+    def visit_IfExp(self, node: ast.IfExp) -> Iterable[str]:
+        with self.prec_ctx("?:"):
+            yield from self.visit(node.test)
+            yield " ? "
+            yield from self.visit(node.body)
+            yield " : "
+            yield from self.visit(node.orelse)
+
+    def visit_Yield(self, node: ast.Yield) -> Iterable[str]:
+        #if CoroutineMode.GENERATOR in self.generator:
+        #    yield "co_yield"
+        #    yield from self.prec("co_yield").visit(node.value)
+        #elif CoroutineMode.FAKE in self.generator:
+        #    yield "return"
+        #    yield from self.visit(node.value)
+        #else:
+        #    raise NotImplementedError(node)
+        yield "co_yield"
+        yield from self.prec("co_yield").visit(node.value)
+
+    def visit_ListComp(self, node: ast.ListComp) -> Iterable[str]:
+        if len(node.generators) != 1:
+            raise NotImplementedError("Multiple generators not handled yet")
+        gen: ast.comprehension = node.generators[0]
+        yield "mapFilter([]("
+        yield from self.visit(node.input_item_type)
+        yield from self.visit(gen.target)
+        yield ") { return "
+        yield from self.visit(node.elt)
+        yield "; }, "
+        yield from self.visit(gen.iter)
+        if gen.ifs:
+            yield ", "
+            yield "[]("
+            yield from self.visit(node.input_item_type)
+            yield from self.visit(gen.target)
+            yield ") { return "
+            yield from self.visit(gen.ifs_node)
+            yield "; }"
+        yield ")"
+        # iter_type = get_iter(self.visit(gen.iter))
+        # next_type = get_next(iter_type)
+        # virt_scope = self.scope.child(ScopeKind.FUNCTION_INNER)
+        # from transpiler import ScoperBlockVisitor
+        # visitor = ScoperBlockVisitor(virt_scope)
+        # visitor.visit_assign_target(gen.target, next_type)
+        # res_item_type = visitor.expr().visit(node.elt)
+        # for if_ in gen.ifs:
+        #     visitor.expr().visit(if_)
+        # return PyList(res_item_type)
\ No newline at end of file

typon/trans/transpiler/phases/emit_cpp/function.py

 import ast
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import Iterable, Optional
 
-
+from transpiler.phases.emit_cpp.expr import ExpressionVisitor
 from transpiler.phases.typing.scope import Scope
-from transpiler.phases.emit_cpp.visitors import NodeVisitor, flatmap
+from transpiler.phases.emit_cpp.visitors import NodeVisitor, flatmap, CoroutineMode
 from transpiler.phases.typing.types import CallableInstanceType, BaseType
 
 
@@ -23,167 +23,166 @@ def emit_function(name: str, func: CallableInstanceType) -> Iterable[str]:
 
 
 
-if False:
-    @dataclass
-    class BlockVisitor(NodeVisitor):
-        scope: Scope
-        #generator: CoroutineMode = field(default=CoroutineMode.SYNC, kw_only=True)
-
-        def expr(self) -> ExpressionVisitor:
-            return ExpressionVisitor(self.scope, self.generator)
+@dataclass
+class BlockVisitor(NodeVisitor):
+    scope: Scope
+    generator: CoroutineMode = field(default=CoroutineMode.SYNC, kw_only=True)
+
+    def expr(self) -> ExpressionVisitor:
+        return ExpressionVisitor(self.scope, self.generator)
+
+    def visit_Pass(self, node: ast.Pass) -> Iterable[str]:
+        yield ";"
+
+    # def visit_FunctionDef(self, node: ast.FunctionDef) -> Iterable[str]:
+    #     yield from self.visit_free_func(node)
+
+    # def visit_free_func(self, node: ast.FunctionDef, emission: FunctionEmissionKind) -> Iterable[str]:
+    #     if getattr(node, "is_main", False):
+    #         if emission == FunctionEmissionKind.DECLARATION:
+    #             return
+    #         # Special case handling for Python's interesting way of defining an entry point.
+    #         # I mean, it's not *that* bad, it's just an attempt at retrofitting an "entry point" logic in a scripting
+    #         # language that, by essence, uses "the start of the file" as the implicit entry point, since files are
+    #         # read and executed line-by-line, contrary to usual structured languages that mark a distinction between
+    #         # declarations (functions, classes, modules, ...) and code.
+    #         # Also, for nitpickers, the C++ standard explicitly allows for omitting a `return` statement in the `main`.
+    #         # 0 is returned by default.
+    #         yield "typon::Root root() const"
+    #
+    #         def block():
+    #             yield from node.body
+    #             yield ast.Return()
+    #
+    #         from transpiler.phases.emit_cpp.function import FunctionVisitor
+    #         yield "{"
+    #         yield from self.visit_func_decls(block(), node.scope, CoroutineMode.TASK)
+    #         yield "}"
+    #         return
+    #
+    #     if emission == FunctionEmissionKind.DECLARATION:
+    #         yield f"struct {node.name}_inner {{"
+    #     yield from self.visit_func_new(node, emission)
+    #     if emission == FunctionEmissionKind.DECLARATION:
+    #         yield f"}} {node.name};"
+
+    def visit_func_decls(self, body: list[ast.stmt], inner_scope: Scope, mode = CoroutineMode.ASYNC) -> Iterable[str]:
+        for child in body:
+            from transpiler.phases.emit_cpp.function import FunctionVisitor
+            child_visitor = FunctionVisitor(inner_scope, generator=mode)
+
+            for name, decl in getattr(child, "decls", {}).items():
+                #yield f"decltype({' '.join(self.expr().visit(decl.type))}) {name};"
+                yield from self.visit(decl.type)
+                yield f" {name};"
+            yield from child_visitor.visit(child)
+
+    def visit_func_params(self, args: Iterable[tuple[str, BaseType, Optional[ast.expr]]], emission: FunctionEmissionKind) -> Iterable[str]:
+        for i, (arg, argty, default) in enumerate(args):
+            if i != 0:
+                yield ", "
+            if emission == FunctionEmissionKind.METHOD and i == 0:
+                yield "Self"
+            else:
+                yield from self.visit(argty)
+            yield arg
+            if emission in {FunctionEmissionKind.DECLARATION, FunctionEmissionKind.LAMBDA, FunctionEmissionKind.METHOD} and default:
+                yield " = "
+                yield from self.expr().visit(default)
 
-        def visit_Pass(self, node: ast.Pass) -> Iterable[str]:
+    def visit_func_new(self, node: ast.FunctionDef, emission: FunctionEmissionKind, skip_first_arg: bool = False) -> Iterable[str]:
+        if emission == FunctionEmissionKind.LAMBDA:
+            yield "[&]"
+        else:
+            if emission == FunctionEmissionKind.METHOD:
+                yield "template <typename Self>"
+            yield from self.visit(node.type.return_type)
+            if emission == FunctionEmissionKind.DEFINITION:
+                yield f"{node.name}_inner::"
+            yield "operator()"
+        yield "("
+        padded_defaults = [None] * (len(node.args.args) if node.type.optional_at is None else node.type.optional_at) + node.args.defaults
+        args_iter = zip(node.args.args, node.type.parameters, padded_defaults)
+        if skip_first_arg:
+            next(args_iter)
+        yield from self.visit_func_params(((arg.arg, argty, default) for arg, argty, default in args_iter), emission)
+        yield ")"
+
+        if emission == FunctionEmissionKind.METHOD:
+            yield "const"
+
+        inner_scope = node.inner_scope
+
+        if emission == FunctionEmissionKind.DECLARATION:
             yield ";"
+            return
 
-        # def visit_FunctionDef(self, node: ast.FunctionDef) -> Iterable[str]:
-        #     yield from self.visit_free_func(node)
-
-        def visit_free_func(self, node: ast.FunctionDef, emission: FunctionEmissionKind) -> Iterable[str]:
-            if getattr(node, "is_main", False):
-                if emission == FunctionEmissionKind.DECLARATION:
-                    return
-                # Special case handling for Python's interesting way of defining an entry point.
-                # I mean, it's not *that* bad, it's just an attempt at retrofitting an "entry point" logic in a scripting
-                # language that, by essence, uses "the start of the file" as the implicit entry point, since files are
-                # read and executed line-by-line, contrary to usual structured languages that mark a distinction between
-                # declarations (functions, classes, modules, ...) and code.
-                # Also, for nitpickers, the C++ standard explicitly allows for omitting a `return` statement in the `main`.
-                # 0 is returned by default.
-                yield "typon::Root root() const"
-
-                def block():
-                    yield from node.body
-                    yield ast.Return()
-
-                from transpiler.phases.emit_cpp.function import FunctionVisitor
-                yield "{"
-                yield from self.visit_func_decls(block(), node.scope, CoroutineMode.TASK)
-                yield "}"
-                return
+        if emission == FunctionEmissionKind.LAMBDA:
+            yield "->"
+            yield from self.visit(node.type.return_type)
 
-            if emission == FunctionEmissionKind.DECLARATION:
-                yield f"struct {node.name}_inner {{"
-            yield from self.visit_func_new(node, emission)
-            if emission == FunctionEmissionKind.DECLARATION:
-                yield f"}} {node.name};"
-
-        def visit_func_decls(self, body: list[ast.stmt], inner_scope: Scope, mode = CoroutineMode.ASYNC) -> Iterable[str]:
-            for child in body:
-                from transpiler.phases.emit_cpp.function import FunctionVisitor
-                child_visitor = FunctionVisitor(inner_scope, generator=mode)
-
-                for name, decl in getattr(child, "decls", {}).items():
-                    #yield f"decltype({' '.join(self.expr().visit(decl.type))}) {name};"
-                    yield from self.visit(decl.type)
-                    yield f" {name};"
-                yield from child_visitor.visit(child)
-
-        def visit_func_params(self, args: Iterable[tuple[str, BaseType, Optional[ast.expr]]], emission: FunctionEmissionKind) -> Iterable[str]:
-            for i, (arg, argty, default) in enumerate(args):
-                if i != 0:
-                    yield ", "
-                if emission == FunctionEmissionKind.METHOD and i == 0:
-                    yield "Self"
-                else:
-                    yield from self.visit(argty)
-                yield arg
-                if emission in {FunctionEmissionKind.DECLARATION, FunctionEmissionKind.LAMBDA, FunctionEmissionKind.METHOD} and default:
-                    yield " = "
-                    yield from self.expr().visit(default)
-
-        def visit_func_new(self, node: ast.FunctionDef, emission: FunctionEmissionKind, skip_first_arg: bool = False) -> Iterable[str]:
-            if emission == FunctionEmissionKind.LAMBDA:
-                yield "[&]"
-            else:
-                if emission == FunctionEmissionKind.METHOD:
-                    yield "template <typename Self>"
-                yield from self.visit(node.type.return_type)
-                if emission == FunctionEmissionKind.DEFINITION:
-                    yield f"{node.name}_inner::"
-                yield "operator()"
-            yield "("
-            padded_defaults = [None] * (len(node.args.args) if node.type.optional_at is None else node.type.optional_at) + node.args.defaults
-            args_iter = zip(node.args.args, node.type.parameters, padded_defaults)
-            if skip_first_arg:
-                next(args_iter)
-            yield from self.visit_func_params(((arg.arg, argty, default) for arg, argty, default in args_iter), emission)
-            yield ")"
+        yield "{"
 
-            if emission == FunctionEmissionKind.METHOD:
-                yield "const"
+        class ReturnVisitor(SearchVisitor):
+            def visit_Return(self, node: ast.Return) -> bool:
+                yield True
 
-            inner_scope = node.inner_scope
+            def visit_Yield(self, node: ast.Yield) -> bool:
+                yield True
 
-            if emission == FunctionEmissionKind.DECLARATION:
-                yield ";"
-                return
+            def visit_FunctionDef(self, node: ast.FunctionDef):
+                yield from ()
 
-            if emission == FunctionEmissionKind.LAMBDA:
-                yield "->"
-                yield from self.visit(node.type.return_type)
-
-            yield "{"
-
-            class ReturnVisitor(SearchVisitor):
-                def visit_Return(self, node: ast.Return) -> bool:
-                    yield True
-
-                def visit_Yield(self, node: ast.Yield) -> bool:
-                    yield True
-
-                def visit_FunctionDef(self, node: ast.FunctionDef):
-                    yield from ()
-
-                def visit_ClassDef(self, node: ast.ClassDef):
-                    yield from ()
-
-            has_return = ReturnVisitor().match(node.body)
-
-            yield from self.visit_func_decls(node.body, inner_scope)
-
-            # if not has_return and isinstance(node.type.return_type, Promise):
-            #     yield "co_return;"
-
-            yield "}"
-
-        def visit_lvalue(self, lvalue: ast.expr, declare: bool | list[bool] = False) -> Iterable[str]:
-            if isinstance(lvalue, ast.Tuple):
-                for name, decl, ty in zip(lvalue.elts, declare, lvalue.type.args):
-                    if decl:
-                        yield from self.visit_lvalue(name, True)
-                        yield ";"
-                yield f"std::tie({', '.join(flatmap(self.visit_lvalue, lvalue.elts))})"
-            elif isinstance(lvalue, ast.Name):
-                if lvalue.id == "_":
-                    if not declare:
-                        yield "std::ignore"
-                    return
-                name = self.fix_name(lvalue.id)
-                # if name not in self._scope.vars:
-                # if not self.scope.exists_local(name):
-                #     yield self.scope.declare(name, (" ".join(self.expr().visit(val)), val) if val else None,
-                #                              getattr(val, "is_future", False))
-                if declare:
-                    yield from self.visit(lvalue.type)
-                yield name
-            elif isinstance(lvalue, ast.Subscript):
-                yield from self.expr().visit(lvalue)
-            elif isinstance(lvalue, ast.Attribute):
-                yield from self.expr().visit(lvalue)
-            else:
-                raise NotImplementedError(lvalue)
+            def visit_ClassDef(self, node: ast.ClassDef):
+                yield from ()
 
-        def visit_Assign(self, node: ast.Assign) -> Iterable[str]:
-            if len(node.targets) != 1:
-                raise NotImplementedError(node)
-            yield from self.visit_lvalue(node.targets[0], node.is_declare)
+        has_return = ReturnVisitor().match(node.body)
+
+        yield from self.visit_func_decls(node.body, inner_scope)
+
+        # if not has_return and isinstance(node.type.return_type, Promise):
+        #     yield "co_return;"
+
+        yield "}"
+
+    def visit_lvalue(self, lvalue: ast.expr, declare: bool | list[bool] = False) -> Iterable[str]:
+        if isinstance(lvalue, ast.Tuple):
+            for name, decl, ty in zip(lvalue.elts, declare, lvalue.type.args):
+                if decl:
+                    yield from self.visit_lvalue(name, True)
+                    yield ";"
+            yield f"std::tie({', '.join(flatmap(self.visit_lvalue, lvalue.elts))})"
+        elif isinstance(lvalue, ast.Name):
+            if lvalue.id == "_":
+                if not declare:
+                    yield "std::ignore"
+                return
+            name = self.fix_name(lvalue.id)
+            # if name not in self._scope.vars:
+            # if not self.scope.exists_local(name):
+            #     yield self.scope.declare(name, (" ".join(self.expr().visit(val)), val) if val else None,
+            #                              getattr(val, "is_future", False))
+            if declare:
+                yield from self.visit(lvalue.type)
+            yield name
+        elif isinstance(lvalue, ast.Subscript):
+            yield from self.expr().visit(lvalue)
+        elif isinstance(lvalue, ast.Attribute):
+            yield from self.expr().visit(lvalue)
+        else:
+            raise NotImplementedError(lvalue)
+
+    def visit_Assign(self, node: ast.Assign) -> Iterable[str]:
+        if len(node.targets) != 1:
+            raise NotImplementedError(node)
+        yield from self.visit_lvalue(node.targets[0], node.is_declare)
+        yield " = "
+        yield from self.expr().visit(node.value)
+        yield ";"
+
+    def visit_AnnAssign(self, node: ast.AnnAssign) -> Iterable[str]:
+        yield from self.visit_lvalue(node.target, node.is_declare)
+        if node.value:
             yield " = "
             yield from self.expr().visit(node.value)
-            yield ";"
-
-        def visit_AnnAssign(self, node: ast.AnnAssign) -> Iterable[str]:
-            yield from self.visit_lvalue(node.target, node.is_declare)
-            if node.value:
-                yield " = "
-                yield from self.expr().visit(node.value)
-            yield ";"
+        yield ";"

typon/trans/transpiler/phases/emit_cpp/visitors.py

 import ast
+from enum import Flag
 from itertools import chain
 from typing import Iterable
 
@@ -89,3 +90,11 @@ def join(sep: str, items: Iterable[Iterable[str]]) -> Iterable[str]:
 
 def flatmap(f, items):
     return chain.from_iterable(map(f, items))
+
+class CoroutineMode(Flag):
+    SYNC = 1
+    FAKE = 2 | SYNC
+    ASYNC = 4
+    GENERATOR = 8 | ASYNC
+    TASK = 16 | ASYNC
+    JOIN = 32 | ASYNC
\ No newline at end of file