init

.venv/lib/python3.8/site-packages/mypy/tvar_scope.py

@@ -0,0 +1,108 @@
+from typing import Optional, Dict, Union
+from mypy.types import TypeVarLikeType, TypeVarType, ParamSpecType, ParamSpecFlavor
+from mypy.nodes import ParamSpecExpr, TypeVarExpr, TypeVarLikeExpr, SymbolTableNode
+
+
+class TypeVarLikeScope:
+    """Scope that holds bindings for type variables and parameter specifications.
+
+    Node fullname -> TypeVarLikeType.
+    """
+
+    def __init__(self,
+                 parent: 'Optional[TypeVarLikeScope]' = None,
+                 is_class_scope: bool = False,
+                 prohibited: 'Optional[TypeVarLikeScope]' = None) -> None:
+        """Initializer for TypeVarLikeScope
+
+        Parameters:
+          parent: the outer scope for this scope
+          is_class_scope: True if this represents a generic class
+          prohibited: Type variables that aren't strictly in scope exactly,
+                      but can't be bound because they're part of an outer class's scope.
+        """
+        self.scope: Dict[str, TypeVarLikeType] = {}
+        self.parent = parent
+        self.func_id = 0
+        self.class_id = 0
+        self.is_class_scope = is_class_scope
+        self.prohibited = prohibited
+        if parent is not None:
+            self.func_id = parent.func_id
+            self.class_id = parent.class_id
+
+    def get_function_scope(self) -> 'Optional[TypeVarLikeScope]':
+        """Get the nearest parent that's a function scope, not a class scope"""
+        it: Optional[TypeVarLikeScope] = self
+        while it is not None and it.is_class_scope:
+            it = it.parent
+        return it
+
+    def allow_binding(self, fullname: str) -> bool:
+        if fullname in self.scope:
+            return False
+        elif self.parent and not self.parent.allow_binding(fullname):
+            return False
+        elif self.prohibited and not self.prohibited.allow_binding(fullname):
+            return False
+        return True
+
+    def method_frame(self) -> 'TypeVarLikeScope':
+        """A new scope frame for binding a method"""
+        return TypeVarLikeScope(self, False, None)
+
+    def class_frame(self) -> 'TypeVarLikeScope':
+        """A new scope frame for binding a class. Prohibits *this* class's tvars"""
+        return TypeVarLikeScope(self.get_function_scope(), True, self)
+
+    def bind_new(self, name: str, tvar_expr: TypeVarLikeExpr) -> TypeVarLikeType:
+        if self.is_class_scope:
+            self.class_id += 1
+            i = self.class_id
+        else:
+            self.func_id -= 1
+            i = self.func_id
+        if isinstance(tvar_expr, TypeVarExpr):
+            tvar_def: TypeVarLikeType = TypeVarType(
+                name,
+                tvar_expr.fullname,
+                i,
+                values=tvar_expr.values,
+                upper_bound=tvar_expr.upper_bound,
+                variance=tvar_expr.variance,
+                line=tvar_expr.line,
+                column=tvar_expr.column
+            )
+        elif isinstance(tvar_expr, ParamSpecExpr):
+            tvar_def = ParamSpecType(
+                name,
+                tvar_expr.fullname,
+                i,
+                flavor=ParamSpecFlavor.BARE,
+                upper_bound=tvar_expr.upper_bound,
+                line=tvar_expr.line,
+                column=tvar_expr.column
+            )
+        else:
+            assert False
+        self.scope[tvar_expr.fullname] = tvar_def
+        return tvar_def
+
+    def bind_existing(self, tvar_def: TypeVarLikeType) -> None:
+        self.scope[tvar_def.fullname] = tvar_def
+
+    def get_binding(self, item: Union[str, SymbolTableNode]) -> Optional[TypeVarLikeType]:
+        fullname = item.fullname if isinstance(item, SymbolTableNode) else item
+        assert fullname is not None
+        if fullname in self.scope:
+            return self.scope[fullname]
+        elif self.parent is not None:
+            return self.parent.get_binding(fullname)
+        else:
+            return None
+
+    def __str__(self) -> str:
+        me = ", ".join('{}: {}`{}'.format(k, v.name, v.id) for k, v in self.scope.items())
+        if self.parent is None:
+            return me
+        return "{} <- {}".format(str(self.parent), me)