Gathers list of expressions in Apple Mail rules, which in my use simply gathers a list of email addresses, then formats them into a procmail rule.

list-of-addresses-in-rule.applescript

set l to {}
set r to "Archive" --Apple Mail Rule from which to pull addresses
set f to "Archive" --Name of folder to move messages from sender to

tell application "Mail"
	set m to properties of rule conditions of rule r
	repeat with v in m
		set p to the expression of v
		set l to l & ".*" & p & "|" as list
	end repeat
end tell

return ":0:" & "
" & "* ^From:" & l & "
" & "." & f & "/"