Avoid cluttering the home directory

Currently the history file is unconditionally written to $HOME/.radian_history. Ideally this should be configurable, but at the very least the default location should follow XDG base dir conventions (i.e. default to$HOME/.local/share/radian/history).

(On macOS there’s an alternative convention to use $HOME/Library/Application Support but from experience applications are split 50/50 about whether they use that rather than XDG, and both are fine.)

[randy3k]

My bad, I am not very familiar with the XDG things, fixed 453e3ff.

[randy3k]

Future updated.

# where the global history is stored, environmental variables will be expanded
# note that "~" is expanded to %USERPROFILE% in Windows
options(radian.global_history_file = "~/.radian_history")
# the filename that local history is stored, this file would be used instead of
# `radian.global_history_file` if it exists in the current working directory
options(radian.local_history_file = ".radian_history")

— Incidentally, R itself does this badly: you can’t have a custom user profile configuration in addition to directory-local configuration (because R_PROFILE_USER overrides that).

Ahh, good point. radian should load both global and local profiles if they both exist.