updating and refactoring codebase for improved performance and maintainability

SYS/cli_parsing.py

@@ -10,18 +10,45 @@ import re
 from typing import Any, Callable, Dict, List, Optional, Set, Tuple
 from SYS.logger import debug
 
-# Prompt-toolkit lexer types are optional at import time; fall back to lightweight
-# stubs if prompt_toolkit is not available so imports remain safe for testing.
-try:
-    from prompt_toolkit.document import Document
-    from prompt_toolkit.lexers import Lexer as _PTK_Lexer
-except Exception:  # pragma: no cover - optional dependency
-    Document = object  # type: ignore
-    # Fallback to a simple object when prompt_toolkit is not available
-    _PTK_Lexer = object  # type: ignore
+# Prompt-toolkit lexer types are optional and expensive (~300ms). Use find_spec
+# to detect availability without importing, then lazy-load on first use.
+import importlib.util as _importlib_util
+_PTK_AVAILABLE: bool = _importlib_util.find_spec("prompt_toolkit") is not None
 
-# Expose a stable name used by the rest of the module
-Lexer = _PTK_Lexer
+_ptk_Document: Any = None
+_ptk_Lexer: Any = None
+
+
+def _get_ptk_Document() -> Any:
+    global _ptk_Document
+    if _ptk_Document is None:
+        if _PTK_AVAILABLE:
+            from prompt_toolkit.document import Document as _Doc
+            _ptk_Document = _Doc
+        else:
+            _ptk_Document = object
+    return _ptk_Document
+
+
+def _get_ptk_Lexer() -> Any:
+    global _ptk_Lexer
+    if _ptk_Lexer is None:
+        if _PTK_AVAILABLE:
+            from prompt_toolkit.lexers import Lexer as _Lex
+            _ptk_Lexer = _Lex
+        else:
+            _ptk_Lexer = object
+    return _ptk_Lexer
+
+
+# Stable aliases: these resolve lazily the first time they are accessed.
+# Code that does `isinstance(x, Document)` or `class Foo(Lexer)` at class-body
+# time needs the real object, so we keep module-level names that proxy to the
+# lazy getters via __getattr__ on the module.  Callers that reference
+# Document/Lexer INSIDE functions will always get the real class.
+# Populate the module-level names now so that class bodies below can inherit.
+Document: Any = _get_ptk_Document()
+Lexer: Any = _get_ptk_Lexer()
 
 # Pre-compiled regexes for the lexer (avoid recompiling on every call)
 TOKEN_PATTERN = re.compile(