feat: add __repr__ to engines

kani/engines/anthropic/engine.py

@@ -153,7 +153,6 @@ def __init__(
         self.hyperparams = hyperparams
 
         # token counting - claude 3+ does not release tokenizer so we have to do heuristics and cache
-        self.token_cache = {}
         if model.startswith("claude-2"):
             # anthropic async client loads a json file using anyio for some reason; hook into the underlying loader
             # noinspection PyProtectedMember

kani/engines/base.py

@@ -132,6 +132,18 @@ async def close(self):
         """Optional: Clean up any resources the engine might need."""
         pass
 
+    # ==== internal ====
+    __ignored_repr_attrs__ = ("token_cache",)
+
+    def __repr__(self):
+        """Default: generate a repr based on the instance's __dict__."""
+        attrs = ", ".join(
+            f"{name}={value!r}"
+            for name, value in self.__dict__.items()
+            if name not in self.__ignored_repr_attrs__ and not name.startswith("_")
+        )
+        return f"{type(self).__name__}({attrs})"
+
 
 # ==== utils ====
 class WrapperEngine(BaseEngine):
@@ -174,6 +186,9 @@ def function_token_reserve(self, functions: list[AIFunction]) -> int:
     async def close(self):
         return await self.engine.close()
 
+    def __repr__(self):
+        return f"{type(self).__name__}(engine={self.engine!r})"
+
     # all other attributes are caught by this default passthrough handler
     def __getattr__(self, item):
         return getattr(self.engine, item)

kani/engines/openai/engine.py

@@ -231,3 +231,9 @@ def _function_token_reserve_impl(self, functions):
 
     async def close(self):
         await self.client.close()
+
+    def __repr__(self):
+        return (
+            f"{type(self).__name__}(model={self.model}, max_context_size={self.max_context_size},"
+            f" hyperparams={self.hyperparams})"
+        )