feat: expose Python function job results

python/src/function.rs

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: Apache-2.0
+// SPDX-FileCopyrightText: Copyright The LanceDB Authors
+
+use arrow::pyarrow::ToPyArrow;
+use pyo3::{Bound, Py, PyAny, PyResult, Python, pyclass, pymethods, types::PyTuple};
+
+/// Immutable first-class Function handle backed by the exact Rust value.
+#[pyclass(frozen, skip_from_py_object)]
+#[derive(Clone)]
+pub struct Function {
+    inner: lancedb::function::Function,
+}
+
+impl Function {
+    pub(crate) fn new(inner: lancedb::function::Function) -> Self {
+        Self { inner }
+    }
+
+    /// Crate-private accessor for later call-authoring slices.
+    #[allow(dead_code)]
+    pub(crate) fn inner(&self) -> &lancedb::function::Function {
+        &self.inner
+    }
+}
+
+#[pymethods]
+impl Function {
+    #[getter]
+    fn id(&self) -> &str {
+        self.inner.id().as_str()
+    }
+
+    #[getter]
+    fn parameters<'py>(&self, py: Python<'py>) -> PyResult<Bound<'py, PyTuple>> {
+        let parameters = self.inner.signature().parameters();
+        let mut pairs = Vec::with_capacity(parameters.len());
+        for parameter in parameters {
+            let data_type = parameter.data_type().to_pyarrow(py)?;
+            pairs.push((parameter.name(), data_type));
+        }
+        PyTuple::new(py, pairs)
+    }
+
+    #[getter]
+    fn output_type(&self, py: Python<'_>) -> PyResult<Py<PyAny>> {
+        self.inner
+            .signature()
+            .output()
+            .data_type()
+            .to_pyarrow(py)
+            .map(|obj| obj.unbind())
+    }
+
+    #[getter]
+    fn output_nullable(&self) -> bool {
+        self.inner.signature().output().nullable()
+    }
+
+    fn __repr__(&self) -> String {
+        format!("Function(id={:?})", self.inner.id().as_str())
+    }
+}