Add slack example

examples/slack/app/markdown.py

@@ -0,0 +1,53 @@
+import re
+
+
+# Conversion from Slack mrkdwn to OpenAI markdown
+# See also: https://api.slack.com/reference/surfaces/formatting#basics
+def slack_to_markdown(content: str) -> str:
+    # Split the input string into parts based on code blocks and inline code
+    parts = re.split(r"(```.+?```|`[^`\n]+?`)", content)
+
+    # Apply the bold, italic, and strikethrough formatting to text not within code
+    result = ""
+    for part in parts:
+        if part.startswith("```") or part.startswith("`"):
+            result += part
+        else:
+            for o, n in [
+                (r"\*(?!\s)([^\*\n]+?)(?<!\s)\*", r"**\1**"),  # *bold* to **bold**
+                (r"_(?!\s)([^_\n]+?)(?<!\s)_", r"*\1*"),  # _italic_ to *italic*
+                (r"~(?!\s)([^~\n]+?)(?<!\s)~", r"~~\1~~"),  # ~strike~ to ~~strike~~
+            ]:
+                part = re.sub(o, n, part)
+            result += part
+    return result
+
+
+# Conversion from OpenAI markdown to Slack mrkdwn
+# See also: https://api.slack.com/reference/surfaces/formatting#basics
+def markdown_to_slack(content: str) -> str:
+    # Split the input string into parts based on code blocks and inline code
+    parts = re.split(r"(```.+?```|`[^`\n]+?`)", content)
+
+    # Apply the bold, italic, and strikethrough formatting to text not within code
+    result = ""
+    for part in parts:
+        if part.startswith("```") or part.startswith("`"):
+            result += part
+        else:
+            for o, n in [
+                (
+                    r"\*\*\*(?!\s)([^\*\n]+?)(?<!\s)\*\*\*",
+                    r"_*\1*_",
+                ),  # ***bold italic*** to *_bold italic_*
+                (
+                    r"(?<![\*_])\*(?!\s)([^\*\n]+?)(?<!\s)\*(?![\*_])",
+                    r"_\1_",
+                ),  # *italic* to _italic_
+                (r"\*\*(?!\s)([^\*\n]+?)(?<!\s)\*\*", r"*\1*"),  # **bold** to *bold*
+                (r"__(?!\s)([^_\n]+?)(?<!\s)__", r"*\1*"),  # __bold__ to *bold*
+                (r"~~(?!\s)([^~\n]+?)(?<!\s)~~", r"~\1~"),  # ~~strike~~ to ~strike~
+            ]:
+                part = re.sub(o, n, part)
+            result += part
+    return result