refactor(duckdb): use lambda to define backend operations

ibis/backends/duckdb/registry.py

@@ -107,28 +107,13 @@ def _literal(_, op):
     return sa.cast(sa.literal(value), sqla_type)
 
 
-def _array_column(t, op):
-    (arg,) = op.args
-    sqla_type = to_sqla_type(op.output_dtype)
-    return sa.cast(sa.func.list_value(*map(t.translate, arg)), sqla_type)
-
-
 def _neg_idx_to_pos(array, idx):
     if_ = getattr(sa.func, "if")
     arg_length = sa.func.array_length(array)
     return if_(idx < 0, arg_length + sa.func.greatest(idx, -arg_length), idx)
 
 
-def _struct_field(t, op):
-    return sa.func.struct_extract(
-        t.translate(op.arg),
-        sa.text(repr(op.field)),
-        type_=to_sqla_type(op.output_dtype),
-    )
-
-
-def _regex_extract(t, op):
-    string, pattern, index = map(t.translate, op.args)
+def _regex_extract(string, pattern, index):
     result = sa.case(
         [
             (
@@ -149,8 +134,7 @@ def _regex_extract(t, op):
     return result
 
 
-def _json_get_item(t, op):
-    left, path = map(t.translate, op.args)
+def _json_get_item(left, path):
     # Workaround for https://github.com/duckdb/duckdb/issues/5063
     # In some situations duckdb silently does the wrong thing if
     # the path is parametrized.
@@ -197,7 +181,12 @@ def _struct_column(t, op):
 
 operation_registry.update(
     {
-        ops.ArrayColumn: _array_column,
+        ops.ArrayColumn: (
+            lambda t, op: sa.cast(
+                sa.func.list_value(*map(t.translate, op.cols)),
+                to_sqla_type(op.output_dtype),
+            )
+        ),
         ops.ArrayConcat: fixed_arity(sa.func.array_concat, 2),
         ops.ArrayRepeat: fixed_arity(
             lambda arg, times: sa.func.flatten(
@@ -222,7 +211,13 @@ def _struct_column(t, op):
         # TODO: map operations, but DuckDB's maps are multimaps
         ops.Modulus: fixed_arity(operator.mod, 2),
         ops.Round: _round,
-        ops.StructField: _struct_field,
+        ops.StructField: (
+            lambda t, op: sa.func.struct_extract(
+                t.translate(op.arg),
+                sa.text(repr(op.field)),
+                type_=to_sqla_type(op.output_dtype),
+            )
+        ),
         ops.TableColumn: _table_column,
         ops.TimestampDiff: fixed_arity(sa.func.age, 2),
         ops.TimestampFromUNIX: _timestamp_from_unix,
@@ -232,7 +227,7 @@ def _struct_column(t, op):
             lambda *_: sa.cast(sa.func.now(), sa.TIMESTAMP),
             0,
         ),
-        ops.RegexExtract: _regex_extract,
+        ops.RegexExtract: fixed_arity(_regex_extract, 3),
         ops.RegexReplace: fixed_arity(
             lambda *args: sa.func.regexp_replace(*args, "g"), 3
         ),
@@ -255,7 +250,7 @@ def _struct_column(t, op):
         ops.ArgMin: reduction(sa.func.min_by),
         ops.ArgMax: reduction(sa.func.max_by),
         ops.BitwiseXor: fixed_arity(sa.func.xor, 2),
-        ops.JSONGetItem: _json_get_item,
+        ops.JSONGetItem: fixed_arity(_json_get_item, 2),
         ops.RowID: lambda *_: sa.literal_column('rowid'),
         ops.StringToTimestamp: fixed_arity(sa.func.strptime, 2),
     }