Autoreplace content with rich content (hashtags to links to hashtags)

[mitar]

Is there a way to autoreplace content with ricth/HTML content as user types it in? For example, if user types in an URL, I would like that this URL automatically becomes a link. If user types in a hashtag, I would like to automatically create a link to list of posts with that tag on my blog. If user mentions another user with @ then I would like to make a link to that user's profile page on my site. Sometimes I would like that the output text is not the same as input, for example, when you on GitHub link to a ticket with full URL, only project name and issue number are displayed, while still linking to the full URL. Same with link shorteners. Is this possible?