Could you please provide a reproduction? Please specify inputs, actual outputs and expected outputs.

use std::io::{self, Write};
use tabwriter::{Alignment, TabWriter};

fn main() {
    // No trailing \t, last col is not right-aligned
    let mut writer = TabWriter::new(io::stdout()).alignment(Alignment::Right);
    write!(&mut writer, "col1\tcol2\tcol3\n").unwrap();
    write!(&mut writer, "1\t2\t3\n").unwrap();
    writer.flush().unwrap();
    // Trailing \t, last col is right-aligned
    let mut writer1 = TabWriter::new(io::stdout()).alignment(Alignment::Right);
    write!(&mut writer1, "col1\tcol2\tcol3\t\n").unwrap();
    write!(&mut writer1, "1\t2\t3\t\n").unwrap();
    writer1.flush().unwrap();
}

Output:

col1  col2  col3
   1     2  3
col1  col2  col3  
   1     2     3  

Expected output:

col1  col2  col3
   1     2     3
col1  col2  col3  
   1     2     3  

That does not seem expected to me. Patches are welcome.

cc @alex-ozdemir

Thanks for looking into this. I came up with that workaround of using a trailing tab by reading the original thread about alignment here: #24 (comment)

Trailing tabs work for me but I think it should be mentioned in the docs if it cannot be easily fixed.

I looked at Go's implementation of tabwriter at https://golang.org/pkg/text/tabwriter/ and it seems that it shows exactly the same behavior (look at the trailing tab example). So maybe you want to keep it that way to be compatible with the Go tabwriter.

Still, I think it is kind of surprising to the user if he wants to output a table with tabwriter and the last column is not right aligned, despite specifying Alignment::Right.

I guess if it is documented properly like the Go version it's ok, because the user can always output a trailing \t.

Basically we have two options:

• Fix that behavior so the last cell is also right/center aligned.
• Keep it how it is and add a documentation that you need to add a trailing \t. for right/center alignment.

Since the crate shares its name with the Go package, I think it is reasonable to keep it compatible with it. Also, when outputting a table row, adding a \t after each element is easier than having a special case for the first element. It is basically the same as considering \t as a cell-ending token visa a cell-separating token.

I think the owner of the package should decide.

It's been a long time since I've looked into the implementation here.

If there's an easy way to fix this that doesn't involve completely rewriting everything, then we should do it.

There was never any intent on my part to be specifically compatible with Go's tabwriter package. Go just inspired this crate.