"Jordan DeLong" <fracture@allusion.net> wrote in message news:20050601032618.GA23098@allusion.net...

First; pre-emptive apologies if this should be sent to boost-users instead of here (or I guess the Mod can nuke it and tell me). I figured I should send it here because it's more of a design issue than a "how do I use this" issue...

path::begin() is defined as returning an 'iterator' (not a const_iterator), so I figured I'd be able to write to it.

The docs describe iterator as " A const iterator..."

I wrote some code which did something like:

fs::path p; /*...*/ for (fs::path::iterator it = p.begin(); it != p.end(); it++) if (*it == "FOO") *it = "BAR";

This errors because operator* on the iterator type returns a const string&.

So: was this a deliberate design decision? I don't see anything about this in the design rationale stuff in the docs for Boost.Filesystem. Is there a good reason not to allow people to use the iterator to modify individual path elements?

Doing so would require actually maintaining elements internally as individual elements, say in a vector of strings. That would be pretty inefficient for most uses of path, just to support such uncommon usage. Instead, rewrite your code something like this: fs::path p; /*...*/ fs::new_path new_p; for (fs::path::iterator it = p.begin(); it != p.end(); it++) if (*it == "FOO") new_path /= "BAR"; else new_path /= *it; HTH, --Beman