In this file I'll try to explain some design decisions and how deer works.
DEER_DIRNAME
The full path to the current directory, without the trailing slash.
DEER_BASENAME
An associative array mapping the dirnames to the files or directories focuesed there.
DEER_BASENAME[$DEER_DIRNAME]
The name of the currently selected file or directory.
Due to the special case of the root directory (/), simply using
$DEER_DIRNAME/$DEER_BASENAME[$DEER_DIRNAME] to get the full path to the selected
directory is not sufficient as it would result in a double slash.
Currently I use ${DEER_DIRNAME%/}/$DEER_BASENAME[$DEER_DIRNAME] to eliminate one
slash in that corner case. It complicates the code in a few places but
it's more maintainable than keeping the slash in DEER_BASENAME and
concatenating dirname with basename without the additional slash in
between (it was the case up until recently).
DEER_FILTER
An associative array mapping the dirnames to the filter to be applied
there. It's modified in the function deer-enter. If the directory
does not exist in that map, it's value should be assumed to be *.
The prefered notation is quite ugly but it works:
${DEER_FILTER[$DEER_DIRNAME]:-'*'}
OLD_LBUFFER and OLD_RBUFFER
The line buffer stored to restore the LBUFFER and RBUFFER contents
later (in the deer-restore function) after adding the selected files
to them.
PREDISPLAY
The built-in variable used to display the preview of the left side of
the buffer (OLD_LBUFFER).
POSTDISPLAY
Used to display the status information. Currently only displays the applied filter if any.