In an SDL model contains a files clause bringing in a directory:
files
dir;
{
return dir;
}
And the directory contains a file with an embedded backslash in its name, then evaluating the model will produce an error like this:
0/Error: Not found opening `foo\bar'.
0/Error: Vesta evaluation failure; exiting.
The evaluator changes in vesta/eval/111 seem to have caused this to start happening, though the bug was actually latent in shared code.
In general there's confusion in the Vesta code caused by treating either a forward slash or a backslash as a filename separator. This comes from a partial attempt made by the original developers to support operating systems which use backslash as a path separator (rather then the forward slash used by UNIX). This is just one example of this problem.
The trivial solution in this case is to change the IsDelimiter function defined in Files.C in the evaluator code to only return true for the forward slash and not the backslash.