feat(api): improve repr of deferred functions

ibis/expr/deferred.py

@@ -220,7 +220,10 @@ def __init__(self, func: Any, *args: Any, **kwargs: Any) -> None:
     def __repr__(self) -> str:
         params = [repr(a) for a in self._args]
         params.extend(f"{k}={v!r}" for k, v in self._kwargs.items())
-        return f"{self._func!r}({', '.join(params)})"
+        # Repr directly wrapped functions as their name, fallback to repr for
+        # deferred objects or callables without __name__ otherwise
+        func = getattr(self._func, "__name__", "") or repr(self._func)
+        return f"{func}({', '.join(params)})"
 
     def _resolve(self, param: Any) -> Any:
         func = _resolve(self._func, param)

ibis/expr/tests/test_deferred.py

@@ -8,6 +8,7 @@
 
 import ibis
 from ibis import _
+from ibis.expr.deferred import deferred_apply
 
 
 @pytest.fixture
@@ -100,6 +101,19 @@ def test_method_kwargs(table):
     assert repr(expr) == "_.a.log(base=_.b)"
 
 
+def test_deferred_apply(table):
+    expr = deferred_apply(operator.add, _.a, 2)
+    res = expr.resolve(table)
+    assert res.equals(table.a + 2)
+    assert repr(expr) == "add(_.a, 2)"
+
+    func = lambda a, b: a + b
+    expr = deferred_apply(func, _.a, 2)
+    res = expr.resolve(table)
+    assert res.equals(table.a + 2)
+    assert func.__name__ in repr(expr)
+
+
 @pytest.mark.parametrize(
     "symbol, op",
     [