Glutin sends both a received character and the key pressed event when a
key is pressed. Because delete and backspace are mapped in reverse by
terminal standards, we ignore the received character 0x07 and 0x7f
values. However, this breaks Control-H since this normally sends 0x07 as
well. The fix here adds handling for Control-H through the input
tracking system.
The default characters sent for this were incorrect. Delete now sends
xterm-compatible escapes (dch1, kdch1), and Backspace sends the delete
code 0x7f.
It's a generic impl of `input::Notify` for `Write` types; as such, it
seems completely reasonable to include in the input module. Moving it
also serves to declutter main.
There's a number of keys/combinations that should emit escape sequences
to the PTY when triggered. This commit adds a framework to support that.
The input::Processor is a type which tracks state of modifier keys. When
special keys (like arrow, function) are detected, the processor pulls up
a list of candidate escapes to send, and picks the first one based on
terminal mode and active modifier keys. The input::Processor is generic
over the thing receiving the escape sequences, the input::Notify type.
Included is a wrapper for `&mut io::Write` which implements
input::Notify and is currently used to connect the processor to the PTY
stream.
This added handling of the APP_CURSOR mode which changes affects input
processing.
Joe Wilm