[texhax] Alignment in a \newwrite file?

[Rodolfo Medina]

Thanks to Oleg Katsitadze and Robin Fairbairns's precious help.
The problem seems to be worked out now.
It came up because the `bluefile.tex' 
had not been created yet at the moment of \input,
and some kind of fileexistence test was necessary.
Both the \testfileexistence eplain command and the \testin macro
do the job very well, it seems.

It is curious that, if I want to insert a \refn{label} 
inside a `\putstuffoverthere' command,
I have to write \noexpand\refn{label} instead of simply \refn{label}.
But it *does* expand actually, when it has to.

Cheers,
        Rodolfo