# [texhax] plain TeX: separate items by comma in \write environment

Rodolfo Medina rodolfo.medina at gmail.com
Fri Apr 27 23:07:43 CEST 2018

```"Philip Taylor (RHUoL)" <P.Taylor at Rhul.Ac.Uk> writes:

> Rodolfo Medina wrote:
>
>  Rodolfo Medina <rodolfo.medina at gmail.com> writes:
>
>  Fine, thanks...  but how can I translate it into simple plain TeX,
> i.e. processing the file with `tex test' rather than xetex...?
>
> ...in particular, that \ifcsname which is undefined in plain TeX...
>
> With some effort (yours, not mine !). Peter B. very kindly gave us \ifcsname,
> Jonathan K equally kindly gave us \primitive -- I personally cannot imagine
> life without them, nor would I want to go back to those awful 8-bit days. I
> seem to recall that \ifx \csname dict:#1\endcsname \undefined will behave
> similarly to \ifcsname dict:#1\endcsname, but will cause \csname
> dict:#1\endcsname to be \relax as a side-effect. This won't matter in your
> case, because I have deliberately post-defined it as \relax anyway, but it
> should be borne in mind if you decide to use \ifx \csname elsewhere ...
>
> ** Phil.

...Maybe it's high time I knew and used that `etex'...

Thanks...!

Rodolfo

```