input: handle multi-combinations as key sequences

The input code always supported combinations of multiple keys (even in
MPlayer, although there the code was active really only for mouse
buttons). This was arcance and also made the code more complicated. I
only know of a single person who ever made use of this feature.

Remove this feature, and repurpose some of the support code (e.g.
parsing, display of key combinations, etc.) to handle such multi-
combinations as sequences, instead of keys to be pressed at the same
time. This is much simpler and implements the feature requested in
github issue #718.

This commit will probably cause a bunch of regressions, since the input
handling code has some weird corner cases. I couldn't find any problems
when testing, though.

1 files changed, 10 insertions, 0 deletions

diff --git a/DOCS/man/en/input.rst b/DOCS/man/en/input.rst
index 97c42ed811..36a19e9479 100644
--- a/DOCS/man/en/input.rst
+++ b/DOCS/man/en/input.rst
@@ -52,6 +52,16 @@ You can bind multiple commands to one key. For example:
 
 | a show_text "command 1" ; show_text "command 2"
 
+It's also possible to bind a command to a sequence of keys:
+
+| a-b-c show_text "command run after a, b, c have been pressed"
+
+(This is not shown in the general command syntax.)
+
+If ``a`` or ``a-b`` or ``b`` are already bound, this will run all commands. It
+doesn't delay key bindings, and it simply considers the past key history on
+any key press.
+
 List of Input Commands
 ----------------------