From d771f3022ae00f04934cfdb3d41434335ee55831 Mon Sep 17 00:00:00 2001
From: LJ <linghua@cocoindex.io>
Date: Thu, 6 Mar 2025 13:00:58 -0800
Subject: [PATCH] Support struct and table types in Python->Rust type encoding.
 #19

---
 python/cocoindex/typing.py | 49 +++++++++++++++++++++++++++-----------
 1 file changed, 35 insertions(+), 14 deletions(-)

diff --git a/python/cocoindex/typing.py b/python/cocoindex/typing.py
index 2e34f58..c11ec84 100644
--- a/python/cocoindex/typing.py
+++ b/python/cocoindex/typing.py
@@ -1,5 +1,6 @@
 import typing
 import collections
+import dataclasses
 from typing import Annotated, NamedTuple, Any
 
 class Vector(NamedTuple):
@@ -31,18 +32,38 @@ def _get_origin_type_and_metadata(t):
         return (t.__origin__, t.__metadata__)
     return (t, ())
 
-def _type_to_json_value(t, metadata):
+def _dump_fields_schema(cls: type) -> list[dict[str, Any]]:
+    return [
+                {
+                    'name': field.name,
+                    'value_type': _dump_enriched_type(field.type),
+                }
+                for field in dataclasses.fields(cls)
+            ]
+
+def _dump_type(t, metadata):
     origin_type = typing.get_origin(t)
     if origin_type is collections.abc.Sequence or origin_type is list:
-        dim = _find_annotation(metadata, Vector)
-        if dim is None:
-            raise ValueError(f"Vector dimension not found for {t}")
         args = typing.get_args(t)
-        origin_type, metadata = _get_origin_type_and_metadata(args[0])
-        type_json = {
-            'kind': 'Vector',
-            'element_type': _type_to_json_value(origin_type, metadata),
-            'dimension': dim.dim,
+        elem_type, elem_type_metadata = _get_origin_type_and_metadata(args[0])
+        vector_annot = _find_annotation(metadata, Vector)
+        if vector_annot is not None:
+            encoded_type = {
+                'kind': 'Vector',
+                'element_type': _dump_type(elem_type, elem_type_metadata),
+                'dimension': vector_annot.dim,
+            }
+        elif dataclasses.is_dataclass(elem_type):
+            encoded_type = {
+                'kind': 'Table',
+                'row': _dump_fields_schema(elem_type),
+            }
+        else:
+            raise ValueError(f"Unsupported type: {t}")
+    elif dataclasses.is_dataclass(t):
+        encoded_type = {
+            'kind': 'Struct',
+            'fields': _dump_fields_schema(t),
         }
     else:
         type_kind = _find_annotation(metadata, TypeKind)
@@ -61,15 +82,15 @@ def _type_to_json_value(t, metadata):
                 kind = 'Float64'
             else:
                 raise ValueError(f"type unsupported yet: {t}")
-        type_json = { 'kind': kind }
+        encoded_type = { 'kind': kind }
     
-    return type_json
+    return encoded_type
 
-def _enriched_type_to_json_value(t) -> dict[str, Any] | None:
+def _dump_enriched_type(t) -> dict[str, Any] | None:
     if t is None:
         return None
     t, metadata = _get_origin_type_and_metadata(t)
-    enriched_type_json = {'type': _type_to_json_value(t, metadata)}
+    enriched_type_json = {'type': _dump_type(t, metadata)}
     attrs = None
     for attr in metadata:
         if isinstance(attr, TypeAttr):
@@ -85,4 +106,4 @@ def dump_type(t) -> dict[str, Any] | None:
     """
     Convert a Python type to a CocoIndex's type in JSON.
     """
-    return _enriched_type_to_json_value(t)
+    return _dump_enriched_type(t)