Add event parsing plugin?

The applications menu already contains a number of [plugins](https://github.com/elementary/applications-menu/tree/master/lib/synapse-plugins), like:
- [Calculator](https://github.com/elementary/applications-menu/blob/master/lib/synapse-plugins/calculator-plugin.vala): Perform simple calculations
- [Switchboard](https://github.com/elementary/applications-menu/blob/master/lib/synapse-plugins/switchboard-plugin.vala): Open specific Switchboard (System settings pages) directly, like "About" or "Power".
- [Link](https://github.com/elementary/applications-menu/blob/master/lib/synapse-plugins/link-plugin.vala): Type a valid link, like "elementary.io" and it will suggest to open it with your default browser.

I'd like to add a calendar plugin which allows users to add an event to the calendar from the switchboard.
How I would like this to work is that a users types in something like "Lecture on mar 19 at 20:00 at room 9.2" and one of the suggestions would be something like:

> Add event:
> Name: Lecture
> Time: 20:00
> Date: March 19
> Location: room 9.2

Doing it like this could provide feedback on which parts are understood. If the user typed in "Lecture on max 19 at 20:00 at room 9.2" it could suggest something like:

> Add event:
> Name: Lecture on max 29
> Time: 20:00
> Date: ?
> Location: room 9.2

It should probably only be triggered by strings like " on ", " at ", " from" etc. or when that's not reliable enough or would take to much system resources it could require a prefix. Something like "Add event ...".

When the user than selects that option the calendar should probably open with the Add event window pre populated.

This is the type of functionality that show the benefits of native applications over for example web based products.

The calender already has some natural language parsing functionality, but it's quite hard to use. One of the reasons It's hard to use is because there is no (real time) feedback. And the application menu has build in functionality to provide this. The functionality in Calendar is also hard to discover, but I must admit that these application menu plugins are also hard to discover.

Issue on adding natural language parsing info to calendar, which contains more examples:
https://github.com/elementary/calendar/issues/219

More inspiration:
- [Fantastical 2](https://youtu.be/WmiIZU2slwU?t=10s)
- [Fantastical 2 in Alfred](https://www.alfredapp.com/blog/productivity/dont-miss-a-date-with-fantastical-2-and-workflows/)
- [Flashlight calendar plugin](http://flashlight.nateparrott.com/plugin/calendar)