example: update code_embedding/main.py to use new function (#1168)

This reverts commit 4f12ad9.

Author: georgeh0

examples/code_embedding/main.py

@@ -1,20 +1,13 @@
 from dotenv import load_dotenv
 from psycopg_pool import ConnectionPool
 from pgvector.psycopg import register_vector
-from typing import Any
 import functools
 import cocoindex
 import os
 from numpy.typing import NDArray
 import numpy as np
 
 
-@cocoindex.op.function()
-def extract_extension(filename: str) -> str:
-    """Extract the extension of a filename."""
-    return os.path.splitext(filename)[1]
-
-
 @cocoindex.transform_flow()
 def code_to_embedding(
     text: cocoindex.DataSlice[str],
@@ -53,10 +46,12 @@ def code_embedding_flow(
     code_embeddings = data_scope.add_collector()
 
     with data_scope["files"].row() as file:
-        file["extension"] = file["filename"].transform(extract_extension)
+        file["language"] = file["filename"].transform(
+            cocoindex.functions.DetectProgrammingLanguage()
+        )
         file["chunks"] = file["content"].transform(
             cocoindex.functions.SplitRecursively(),
-            language=file["extension"],
+            language=file["language"],
             chunk_size=1000,
             min_chunk_size=300,
             chunk_overlap=300,