Shift lots of shells' history into XDG_DATA_HOME

It's not ideal to set XDG_RUNTIME_DIR in your shell environment,
rather than from your session manager (or systemd, or whatever), since
then you can't reliably provide the same lifetime guarantees that
XDG_RUNTIME_DIR is supposed to have? But this is still preferable to not
having an XDG_RUNTIME_DIR at all, so I'm gonna go with it.

config/zsh/login/langs

@@ -2,14 +2,24 @@
 
 local -a newbins
 
+# docker
+export DOCKER_CONFIG=$XDG_CONFIG_HOME/docker
+
 # go
-[[ -z $GOPATH ]] && export GOPATH=~/.go
-newbins+=(~/.go/bin)
+[[ -z $GOPATH ]] && export GOPATH=$XDG_DATA_HOME/go
+newbins+=($XDG_DATA_HOME/go/bin)
 
 # haskell
 newbins+=(~/.cabal/bin ~/Library/Haskell/bin)
 export STACK_ROOT=$XDG_DATA_HOME/stack
 
+# less
+# not exactly a 'lang' but still
+export LESSHISTFILE=$XDG_DATA_HOME/less/history
+
+# mysql
+export MYSQL_HISTFILE=$XDG_DATA_HOME/mysql/history
+
 # o'caml
 export OPAMROOT=$XDG_DATA_HOME/opam
 [[ -f $OPAMROOT/opam-init/init.zsh ]] && source $OPAMROOT/opam-init/init.zsh
@@ -23,6 +33,9 @@ fi
 
 # ruby
 newbins+=(~/.gem/ruby/*/bin(N) /usr/local/opt/ruby/bin /usr/local/lib/ruby/gems/*/bin(N))
+export BUNDLE_USER_CONFIG=$XDG_CONFIG_HOME/bundle
+export BUNDLE_USER_CACHE=$XDG_CACHE_HOME/bundle
+export BUNDLE_USER_PLUGIN=$XDG_DATA_HOME/bundle
 
 # rust
 export CARGO_HOME=$XDG_DATA_HOME/cargo
@@ -45,6 +58,9 @@ export PHIVE_HOME=$XDG_DATA_HOME/phive
 # there you go, I guess.
 newbins+=($XDG_CONFIG_HOME/composer/vendor/bin)
 
+# postgres
+export PSQL_HISTORY=$XDG_DATA_HOME/psql/history
+
 # python
 export -UT PYTHONPATH pythonpath
 newbins+=(~/Library/Python/*/bin(N))
@@ -54,4 +70,10 @@ export PYENV_ROOT=$XDG_DATA_HOME/pyenv
 export PYENV_SHELL=zsh
 newbins+=($XDG_DATA_HOME/pyenv/shims $HOME/.poetry/bin)
 
+# redis
+export REDISCLI_HISTFILE=$XDG_DATA_HOME/redis/rediscli_history
+
+# sqlite
+export SQLITE_HISTORY=$XDG_DATA_HOME/sqlite/history
+
 path=($newbins $path)

zshenv

@@ -6,6 +6,26 @@
 
 export XDG_CONFIG_HOME XDG_CACHE_HOME XDG_DATA_HOME XDG_STATE_HOME
 
+# The other four XDG directories are very easy, but XDG_RUNTIME_DIR is
+# complicated. It kinda needs to be managed by a systemwide supervisor, like
+# systemd, in order to meet all of the XDG Base Directory specification's
+# requirements? In particular, the directory is supposed to come into being
+# when you log in, live as long as you have any active sessions, and be
+# destroyed when you log out - none of this can easily be done from the shell
+# environment alone, especially on an operating system like macOS where your
+# graphical session wasn't spawned from a shell using something like .xinitrc.
+#
+# We're going to assume XDG_RUNTIME_DIR will have already be set by a
+# systemwide supervisor if it can possibly have been. If it hasn't - say,
+# because we're on macOS - we'll compromise by using TMPDIR. Since TMPDIR has
+# a different lifetime than XDG_RUNTIME_DIR is supposed to, this is an
+# imperfect solution, but it's the best we can do.
+if [[ ! -d $XDG_RUNTIME_DIR ]] && [[ -d $TMPDIR ]]; then
+	export XDG_RUNTIME_DIR=${TMPDIR}xdg-$UID
+	mkdir -p $XDG_RUNTIME_DIR
+	chmod 0700 $XDG_RUNTIME_DIR
+fi
+
 # The real zsh config lives in XDG_CONFIG_HOME! ;)
 : ${ZDOTDIR:=$XDG_CONFIG_HOME/zsh}
 source $ZDOTDIR/zshenv