Support table for markdown file in general parser (#1278)

### What problem does this PR solve?

Support extracting table for markdown file in general parser

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

deepdoc/parser/__init__.py

@@ -16,4 +16,5 @@ from .docx_parser import RAGFlowDocxParser as DocxParser
 from .excel_parser import RAGFlowExcelParser as ExcelParser
 from .ppt_parser import RAGFlowPptParser as PptParser
 from .html_parser import RAGFlowHtmlParser as HtmlParser
-from .json_parser import RAGFlowJsonParser as JsonParser
+from .json_parser import RAGFlowJsonParser as JsonParser
+from .markdown_parser import RAGFlowMarkdownParser as MarkdownParser

deepdoc/parser/markdown_parser.py

@@ -0,0 +1,44 @@
+# -*- coding: utf-8 -*-
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+import re
+
+class RAGFlowMarkdownParser:
+    def __init__(self, chunk_token_num=128):
+        self.chunk_token_num = int(chunk_token_num)
+
+    def extract_tables_and_remainder(self, markdown_text):
+        # Standard Markdown table
+        table_pattern = re.compile(
+            r'''
+            (?:\n|^)                     
+            (?:\|.*?\|.*?\|.*?\n)        
+            (?:\|(?:\s*[:-]+[-| :]*\s*)\|.*?\n) 
+            (?:\|.*?\|.*?\|.*?\n)+
+            ''', re.VERBOSE)
+        tables = table_pattern.findall(markdown_text)
+        remainder = table_pattern.sub('', markdown_text)
+
+        # Borderless Markdown table
+        no_border_table_pattern = re.compile(
+            r'''
+            (?:\n|^)                 
+            (?:\S.*?\|.*?\n)
+            (?:(?:\s*[:-]+[-| :]*\s*).*?\n)
+            (?:\S.*?\|.*?\n)+
+            ''', re.VERBOSE)
+        no_border_tables = no_border_table_pattern.findall(remainder)
+        tables.extend(no_border_tables)
+        remainder = no_border_table_pattern.sub('', remainder)
+
+        return remainder, tables