At 02:23 AM 3/13/2004, John Torjo wrote:
Dear boosters,
I noticed that currently there's no way to get the relative path of path A related to path B. What I mean is, given two **complete** paths, to get the relative path of one related to the other.
To give a real example, I have an application that starts in directory initial_path(). I have several dialogs that allow the user to browse for files. My requirement is, after the user browses for a file, to internally ALWAYS store the path relative to initial_path().
Since there's no way to do this currently, I created my own function. Do you think it could be a useful addition to filesystem library?
It might be useful, but the problem is one of expectations. The function you provided operates only on the lexical path representation; that's OK if that is what is expected but could be a pretty rude shock to a programmer not expecting that behavior. For example, relative_to( "c:/foo", "C:/foo" ) returns "c:/foo", which is probably not what was desired. I'm definitely worried that relative_to() as proposed would come to be viewed as fragile. This is similar to the path equality issue. We are dealing with that by introducing class path relational operators, working at a lexical level, and a function equivalent() which actually performs filesystem operations to determine if two paths refer to the same underlying object. What do others think? --Beman