[O] Link "bracket-types"

[Michael Brand]

Hi all

For the four different Org link "bracket-types" shown below I would
like to have four different faces to be able to distinguish them at
first sight. What is the recommended way to do this?

The four Org link bracket-types by example:

Buffer raw content (or visible-mode):
: 1) 
[[https://en.wikipedia.org/wiki/Filter#References][https://en.wikipedia.org/wiki/Filter]]
: 2) https://en.wikipedia.org/wiki/Filter
: 3) [[https://en.wikipedia.org/wiki/Filter]]
: 4) [[https://en.wikipedia.org/wiki/Filter_(higher-order_function)]]

(To try them out copy the above into an Org buffer and remove the colons.)

Currently rendered all with the same face as:
: 1) https://en.wikipedia.org/wiki/Filter
: 2) https://en.wikipedia.org/wiki/Filter
: 3) https://en.wikipedia.org/wiki/Filter
: 4) https://en.wikipedia.org/wiki/Filter_(higher-order_function)

As you know and can see above 1) to 3) can not be distinguished when
rendered with the default of org-descriptive-links t.

The brackets for 3) are optional as 2) opens the same URL.

The brackets for 4) are mandatory because without them
"_(higher-order_function)" is not fontified and not recognized by
org-open-at-point as part of the Org link any more. I think 4) can be
distinguished from 3) by comparing the bracket content with the part
fontified and/or recognized as Org link when the bracket content
without the brackets is matched/parsed again stand-alone.

org-descriptive-links permanently nil does not seem to be an
alternative as it disturbs text flow and org-fill-paragraph.
org-toggle-link-display does not seem to be an alternative as it would
have to be toggled forth and back on every new window scroll view.

Michael