passing bash variables to expect script or scripting expect from inside bash

pass the value through the environment:

ipaddress=$(<"$file")
export ipaddress

/usr/bin/expect <<'EOD'

spawn sudo sshfs -o StrictHostKeyChecking=accept-new cm4nxd@$env(ipaddress):/ /Volumes/ryzen-server -oallow_other -oauto_xattr -ovolname=ryzen-server
# ..........................................................^^^^^^^^^^^^^^^

(edit 17 hours later) -- Note that the 'EOD' must be quoted. That essentially single quotes the entire heredoc so that the shell does not expand Expect's variables.

don't need the shell: read the file in expect

#!/usr/bin/env expect

set fh [open /Users/cm4nxd/Library/Scripts/current.ip r]
gets $fh ipaddress
close $fh

spawn ... user@$ipaddress ...