Here's a minimal little template (checked):

import std.stdio;

void main()
{
        auto f = File("outfile.txt", "w");
        f.writefln("%s World", "Hello");
        f.close();
}





2010/10/6 Denis Koroskin <2korden@gmail.com>
On Wed, 06 Oct 2010 22:43:42 +0400, Dr. Smith <iam@far.out> wrote:

This should be trivial.  However, I've not found in the documentation (trying
both std.stdio and std.file) how to write to a file in the manner here:

filename.writefln("%s\t%f", someString, someDouble);

... this merely prints filename to screen ... does not create a data file.

In your case, foo.bar(args) == bar(foo, args) - that is call Uniform Function Call Syntax, that is:

filename.writefln("%s\t%f", someString, someDouble); -> writefln(filename, "%s\t%f", someString, someDouble);

which in turn tries using filename as a format.

Try using std.stream. It should be something like this:

File file = new File(fileName, FileMode.OutNew); // open file for writing, create new if none exists
file.writefln("hello, %s!", "world");

Not tested but should work.