Homepage: https://www.gnu.org/software/emacs
Author: Stefan Monnier
Automatically reveal hidden text at point
Reveal mode is a minor mode that makes sure that text around point is always visible. When point enters a region of hidden text, `reveal-mode' temporarily makes it visible. Overlays can also use the `display' property. For them to be revealed, the `reveal-toggle-invisible' property also has to be present, and should be a function to toggle between having a display property and not. This is normally used in conjunction with `outline-minor-mode', `hs-minor-mode', `hide-ifdef-mode', ... It only works with packages that hide text using overlays. Packages can provide special support for it by placing a function in the `reveal-toggle-invisible' property on the symbol used as the value of the `invisible' overlay property. The function is called right after revealing (or re-hiding) the text with two arguments: the overlay and a boolean that's non-nil if we have just revealed the text. When revealing, that function may re-hide some of the text.