"machine code" of page assembly

[Jeff Kingston]

Ted Harding writes:

> There are some advantages in being able to access what you might call the
> "machine code" of page assembly, as you can (up to a point) in [g]troff.
> Are such things totally out of reach in Lout?

Lout's pages are defined as symbols in Lout; these symbols live in
file $(LOUTLIB)/include/dsf, and so in this sense you can certainly
get at the "machine code" of page assembly.  There are practical
difficulties in diving into a mature, complex page layout package and
changing things.

However, the bulk of Ted's mail was about flowing text around
illustrations.  Lout first sets the body text and then inserts
it into pages, so it is not well set up for changing the appearance
of body text depending whether the page is odd or even.  It is just
possible, however, by using cross referencing - one could define a
symbol with a switch (@Case in Lout) that depends on the value of
a preceding cross reference, which itself could be made to depend
on whether the page was odd or even.

Ted'd troff solution would not extend to the optimal paragraph
breaking that users of Lout and TeX have come to expect.  You
could follow the method used to make drop capitals - a horizontal
galley - but hyphenation of galley components has never been
implemented in Lout, so although you could still get an optimal
paragraph wrapped around an illustration, there would be no
hyphenation.

Jeff Kingston