Re: plain TeX: different \hsize and \vsize for odd and even pages (was: plain TeX: different margins for odd and even pages)

On Wed, Apr  8, 2026 at 22:56 (+0100), David Carlisle wrote:

> On Wed, 8 Apr 2026 at 22:29, Jim Diamond <[email protected]> wrote:

>> I haven't looked at output routines in a long time, but as I recall the
>> leftover paragraph bit (after the paragraph has been split) becomes the
>> first \vbox contribution for the new page.

>> As you say, it has been set with a particular \hsize.

>> But is there not some unbox trickery which can be used to create a new
>> paragraph out of the leftover bit?

>> I suspect the unboxing may (or may not) lose some glue explicitly applied,
>> but if the OP's paragraphs are just plain text (sequences of words), and
>> not fancy constructions or math, is this something which might work?


> basically no you can not reflow a box in classic tex.  you can't
> unhyphenate words

That is a very good point!

> and information about whatever glue was discarded at line breaks is
> lost.

Also a good point, but maybe not an issue if the paragraph is just words.

> If the paragraph has colour specials or other whatsits between the lines
> you can not deconstruct the box at all, (well you can attempt vsplit
> rather than lastbox, but that loses more information)

Also good points.  So a general solution is not possible.  But, hyphenation
aside, if one's document is just words (no whatsits, specials, ...), would
unboxing work?

                                Jim