Re: Reading directory names with read-file-name

[Richard Stallman]

    How about allowing READ-DIR to be any predicate, so that the invoker
    of read-file-name can filter file names in arbitrary ways?

This could be made consistent with the new locate-file function.

      I suspect
    that this would subsume read-file-name's existing MUSTMATCH argument
    to some extent, since MUSTMATCH=t would be roughly equivalent to
    READ-DIR=file-exists-p, but I can't think of a cleaner extension
    offhand.

This suggests that we should redefine the MUSTMATCH argument
rather than add a new one.