chore: Migrate RemoteFunctionOp operator to SQLGlot

bigframes/core/compile/sqlglot/expressions/generic_ops.py

@@ -140,6 +140,28 @@ def _(left: TypedExpr, right: TypedExpr) -> sge.Expression:
     return sge.Coalesce(this=left.expr, expressions=[right.expr])
 
 
+@register_unary_op(ops.RemoteFunctionOp, pass_op=True)
+def _(expr: TypedExpr, op: ops.RemoteFunctionOp) -> sge.Expression:
+    routine_ref = op.function_def.routine_ref
+    # Quote project, dataset, and routine IDs to avoid keyword clashes.
+    func_name = (
+        f"`{routine_ref.project}`.`{routine_ref.dataset_id}`.`{routine_ref.routine_id}`"
+    )
+    func = sge.func(func_name, expr.expr)
+
+    if not op.apply_on_null:
+        return sge.Case(
+            ifs=[
+                sge.If(
+                    this=sge.Is(this=expr.expr, expression=sge.Null()), true=expr.expr
+                )
+            ],
+            default=func,
+        )
+
+    return func
+
+
 @register_binary_op(ops.BinaryRemoteFunctionOp, pass_op=True)
 def _(
     left: TypedExpr, right: TypedExpr, op: ops.BinaryRemoteFunctionOp

tests/unit/core/compile/sqlglot/expressions/snapshots/test_generic_ops/test_remote_function_op/out.sql

@@ -0,0 +1,13 @@
+WITH `bfcte_0` AS (
+  SELECT
+    `int64_col`
+  FROM `bigframes-dev`.`sqlglot_test`.`scalar_types`
+), `bfcte_1` AS (
+  SELECT
+    *,
+    `my_project`.`my_dataset`.`my_routine`(`int64_col`) AS `bfcol_1`
+  FROM `bfcte_0`
+)
+SELECT
+  `bfcol_1` AS `int64_col`
+FROM `bfcte_1`

tests/unit/core/compile/sqlglot/expressions/test_generic_ops.py

@@ -168,6 +168,37 @@ def test_astype_json_invalid(
         )
 
 
+def test_remote_function_op(scalar_types_df: bpd.DataFrame, snapshot):
+    from google.cloud import bigquery
+
+    from bigframes.functions import udf_def
+
+    bf_df = scalar_types_df[["int64_col"]]
+    op = ops.RemoteFunctionOp(
+        function_def=udf_def.BigqueryUdf(
+            routine_ref=bigquery.RoutineReference.from_string(
+                "my_project.my_dataset.my_routine"
+            ),
+            signature=udf_def.UdfSignature(
+                input_types=(
+                    udf_def.UdfField(
+                        "x",
+                        bigquery.StandardSqlDataType(
+                            type_kind=bigquery.StandardSqlTypeNames.INT64
+                        ),
+                    ),
+                ),
+                output_bq_type=bigquery.StandardSqlDataType(
+                    type_kind=bigquery.StandardSqlTypeNames.FLOAT64
+                ),
+            ),
+        ),
+        apply_on_null=True,
+    )
+    sql = utils._apply_ops_to_sql(bf_df, [op.as_expr("int64_col")], ["int64_col"])
+    snapshot.assert_match(sql, "out.sql")
+
+
 def test_binary_remote_function_op(scalar_types_df: bpd.DataFrame, snapshot):
     from google.cloud import bigquery