Mew also provides a mechanism to guess a folder by the place where a message that has the same From: field is refiled.
Suppose that piglet has two addresses, piglet@beech.tree.uk and p-p-p@mew.org. pooh wants to refile messages from piglet to +from/piglet no matter what his From: is. This policy can, of course, be implemented if pooh specifies rules explicitly as follows:
(setq mew-refile-guess-alist
'(("From:"
("piglet@beech.tree.uk" . "+from/piglet")
("p-p-p@mew.org" . "+from/piglet"))))
But such a work may bother you. So, first refile a message whose From: is piglet@beech.tree.uk to +from/piglet. At this time, +from/piglet is created. Next, refile a message whose From: is p-p-p@mew.org to +from/piglet. Here Mews learns that p-p-p@mew.org was refiled to +from/piglet. After this, when messages whose From: is p-p-p@mew.org are refiled, +from/piglet is chosen.
For another example, you can refile messages from machinery to +adm/misc without defining an explicit rule.
Information for relationship between From: and folder is stored to "~/Mail/.mew-refile-from-alist". `mew-lisp-max-length' controls the amount of this information as the same as See section Guess by thread.
The function name to provide this feature is `mew-refile-guess-by-from'.
If the value of `mew-refile-guess-from-me-is-special' is `t', `mew-refile-guess-by-from' acts as `mew-refile-guess-by-from-folder'(See section Guess by private folders).