Regarding representation of rich text in text messages

[blueset]

Looking for a general, easy to parse, convert and subset representation of rich text in text messages.

Rich text representation in some IMs:

• Telegram
  Bold, italics, monospaced, monospaced block, link, strikethrough and underline, @ reference. Nesting supported.
  (offset, length, attributes); Markdown subset; HTML subset;
• Slack
  Bold, italics, strikethrough, quote, inline code, block code, list, link, user&channel reference, etc. Nesting allowed.
  mrkdwn (variation of Markdown)
• Discord
  Bold, italics, strikethrough, underline, inline code, code block, syntax highlighting, spoiler alerts. Nesting allowed.
  Markdown subset.
• WeChat
  None.
• Facebook Messenger
  Bold, italic, strikethrough, monospace, codeblock, LaTeX (\(\sin(2\pi)\)).
  Web only.
• QQ (CoolQ Pro)
  Inline image, custom emoticon.
  CoolQ token in messages.
• Line
  Custom emoticon.
  Unicode Private Use Area.
• XMPP (Extension)
  Bold, italics, strikethrough, monospaced, quote. Nesting allowed.
  Markdown subset, extended. (XEP-0393)
• IRC
  None.
• Rocket Chat
  Bold, italic, strikethrough, inline code, image, link. Nesting allowed.
  Markdown subset.
• Skype
  Bold, italic, strikethrough, inline code, code block.
  Markdown-like.

[blueset]

Will try to make markdown as a common syntax as it being the majority base syntax, and an attribute to specify whether the text should be in markdown-like format.

However Markdown is still less organised, and harder to escape compare to HTML (which has a relatively established standard for formatting). I'm still undecided about whether to use HTML or Markdown for this.

[blueset]

Telegram recently added more formatting and nesting support to its bot API. They have resolved to a new variation of Markdown, and extending the existing HTML syntax for the new change.

However, in the background Telegram is using the message entity format, i.e. a mapping of offset, length, entity type and parameters.

Ideas on which format is better and how to establish the spec is welcomed.