Add some type hints in sql/reader/base.py

sql/snsql/sql/reader/base.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+from typing import Type
 from snsql.reader.base import Reader
 from snsql.sql.reader.engine import Engine
 import importlib
@@ -6,7 +8,7 @@
 
 class SqlReader(Reader):
     @classmethod
-    def get_reader_class(cls, engine):
+    def get_reader_class(cls, engine) -> Type[Reader]:
         prefix = ""
         for eng in Engine.known_engines:
             if str(eng).lower() == engine.lower():
@@ -72,10 +74,10 @@ def __init__(self, search_path=None):
         path.  Pass in only the schema part.
     """
 
-    def reserved(self):
+    def reserved(self) -> list[str]:
         return ["select", "group", "on"]
 
-    def schema_match(self, from_query, from_meta):
+    def schema_match(self, from_query: str, from_meta: str) -> bool:
         if from_query.strip() == "" and from_meta in self.search_path:
             return True
         if from_meta.strip() == "" and from_query in self.search_path:
@@ -87,25 +89,25 @@ def schema_match(self, from_query, from_meta):
         if identifier used in query matches identifier
         of metadata object.  Pass in one part at a time.
     """
-    def identifier_match(self, from_query, from_meta):
+    def identifier_match(self, from_query: str, from_meta: str) -> bool:
         return from_query == from_meta
 
     """
         Removes all escaping characters, keeping identifiers unchanged
     """
-    def strip_escapes(self, value):
+    def strip_escapes(self, value: str) -> str:
         return value.replace('"', "").replace("`", "").replace("[", "").replace("]", "")
 
     """
         True if any part of identifier is escaped
     """
-    def is_escaped(self, identifier):
+    def is_escaped(self, identifier: str) -> bool:
         return any([p[0] in ['"', "[", "`"] for p in identifier.split(".") if p != ""])
 
     """
         Converts proprietary escaping to SQL-92.  Supports multi-part identifiers
     """
-    def clean_escape(self, identifier):
+    def clean_escape(self, identifier: str) -> str:
         escaped = []
         for p in identifier.split("."):
             if self.is_escaped(p):
@@ -118,7 +120,7 @@ def clean_escape(self, identifier):
         Returns true if an identifier should
         be escaped.  Checks only one part per call.
     """
-    def should_escape(self, identifier):
+    def should_escape(self, identifier: str) -> bool:
         if self.is_escaped(identifier):
             return False
         if identifier.lower() in self.reserved():