*\input test
 (test.TEX 1 2 (basic.TEX 1 2 3 4)





\array #1\\#2\endarray →\xdef \ident {#1} \vcenter {\halign {\tabskip 0pt\ident \ddt \cr #2\cr }}
#1←\c \ddt \quad ⊗\c 


#2←a⊗b\\c⊗d
\c →\hfill $##$\hfill 
\c →\hfill $##$\hfill 
\ident →\hfill $##$\hfill \ddt \quad ⊗\hfill $##$\hfill 
⊗⊗⊗ restricted horizontal, spacefactor 1.0000
\glue .0000 plus 10000000000.0000
\hyphenation0
\:g a
\hyphenation1
\glue .0000 plus 10000000000.0000
⊗⊗⊗ restricted horizontal, spacefactor 1.0000
⊗⊗⊗ restricted vertical
⊗⊗⊗ restricted vertical
⊗⊗⊗ math
⊗⊗⊗ horizontal, spacefactor 1.0000
\hbox( .0000 + .0000)x 20.0000
⊗⊗⊗ vertical, prevdepth .0000
\glue .0000 plus 1.0000
⊗⊗⊗ current page:
\glue 10.0000
\hbox( .0000 + .0000)x .0000
\glue-12.0000
⊗⊗⊗ nesting level 3
! OK.
<vlist> $\hfill \ddt 
                     \quad \ENDV
<argument> a⊗
             b\\c⊗d
... {\tabskip 0pt\ident \ddt \cr #2
                                   \cr }}
p.2,l.9 c⊗d\endarray
                    $
↑
\\→\cr 
⊗⊗⊗ restricted horizontal, spacefactor 1.0000
\glue .0000 plus 10000000000.0000
\hyphenation0
\:g b
\hyphenation1
\glue .0000 plus 10000000000.0000
⊗⊗⊗ restricted horizontal, spacefactor 1.0000
\unsetbox( 4.4444 + .0000)x 15.2778, glueset 20000000000.0000
.\glue .0000 plus 10000000000.0000
.\hyphenation0
.\:g a
.\hyphenation1
.\glue .0000 plus 10000000000.0000
.\glue 10.0000
⊗⊗⊗ restricted vertical
⊗⊗⊗ restricted vertical
⊗⊗⊗ math
⊗⊗⊗ horizontal, spacefactor 1.0000
\hbox( .0000 + .0000)x 20.0000
⊗⊗⊗ vertical, prevdepth .0000
\glue .0000 plus 1.0000
⊗⊗⊗ current page:
\glue 10.0000
\hbox( .0000 + .0000)x .0000
\glue-12.0000
⊗⊗⊗ nesting level 3
! OK.
<vlist> $\hfill \ddt 
                     \ENDV
\\→\cr 
       
<argument> a⊗b\\
                c⊗d
... {\tabskip 0pt\ident \ddt \cr #2
                                   \cr }}
p.2,l.9 c⊗d\endarray
                    $
↑
⊗⊗⊗ restricted horizontal, spacefactor 1.0000
\glue .0000 plus 10000000000.0000
\hyphenation0
\:g c
\hyphenation1
\glue .0000 plus 10000000000.0000
⊗⊗⊗ restricted horizontal, spacefactor 1.0000
⊗⊗⊗ restricted vertical, prevdepth .0000
\hbox( 6.9444 + .0000)x 19.8611
.\unsetbox( 4.4444 + .0000)x 15.2778, glueset 20000000000.0000
..\glue .0000 plus 10000000000.0000
..\hyphenation0
..\:g a
..\hyphenation1
..\glue .0000 plus 10000000000.0000
..\glue 10.0000
.\unsetbox( 6.9444 + .0000)x 4.5833, glueset 20000000000.0000
..\glue .0000 plus 10000000000.0000
..\hyphenation0
..\:g b
..\hyphenation1
..\glue .0000 plus 10000000000.0000
⊗⊗⊗ restricted vertical
⊗⊗⊗ math
⊗⊗⊗ horizontal, spacefactor 1.0000
\hbox( .0000 + .0000)x 20.0000
⊗⊗⊗ vertical, prevdepth .0000
\glue .0000 plus 1.0000
⊗⊗⊗ current page:
\glue 10.0000
\hbox( .0000 + .0000)x .0000
\glue-12.0000
⊗⊗⊗ nesting level 3
! OK.
<vlist> $\hfill \ddt 
                     \quad \ENDV
<argument> a⊗b\\c⊗
                  d
... {\tabskip 0pt\ident \ddt \cr #2
                                   \cr }}
p.2,l.9 c⊗d\endarray
                    $
↑
⊗⊗⊗ restricted horizontal, spacefactor 1.0000
\glue .0000 plus 10000000000.0000
\hyphenation0
\:g d
\hyphenation1
\glue .0000 plus 10000000000.0000
⊗⊗⊗ restricted horizontal, spacefactor 1.0000
\unsetbox( 4.4444 + .0000)x 14.3056, glueset 20000000000.0000
.\glue .0000 plus 10000000000.0000
.\hyphenation0
.\:g c
.\hyphenation1
.\glue .0000 plus 10000000000.0000
.\glue 10.0000
⊗⊗⊗ restricted vertical, prevdepth .0000
\hbox( 6.9444 + .0000)x 19.8611
.\unsetbox( 4.4444 + .0000)x 15.2778, glueset 20000000000.0000
..\glue .0000 plus 10000000000.0000
..\hyphenation0
..\:g a
..\hyphenation1
..\glue .0000 plus 10000000000.0000
..\glue 10.0000
.\unsetbox( 6.9444 + .0000)x 4.5833, glueset 20000000000.0000
..\glue .0000 plus 10000000000.0000
..\hyphenation0
..\:g b
..\hyphenation1
..\glue .0000 plus 10000000000.0000
⊗⊗⊗ restricted vertical
⊗⊗⊗ math
⊗⊗⊗ horizontal, spacefactor 1.0000
\hbox( .0000 + .0000)x 20.0000
⊗⊗⊗ vertical, prevdepth .0000
\glue .0000 plus 1.0000
⊗⊗⊗ current page:
\glue 10.0000
\hbox( .0000 + .0000)x .0000
\glue-12.0000
⊗⊗⊗ nesting level 3
! OK.
<vlist> $\hfill \ddt 
                     \ENDV
...abskip 0pt\ident \ddt \cr #2\cr 
                                   }}
p.2,l.9 c⊗d\endarray
                    $
↑
)
*
*that worked?\par\vfill\end
Completed for page 1:
\vbox( 480.0000 + .0000)x 353.0000, glueset .0000
.\glue 10.0000
.\hbox( .0000 + .0000)x .0000
.\glue-12.0000
.\glue .0000 plus 1.0000
.\glue .0278
.\hbox( 11.9722 + 6.9722)x 353.0000, glueset .0031
..\hbox( .0000 + .0000)x 20.0000
..\hyphenation0
..\vbox( 18.9444 + .0000)x 20.6944, shifted 6.9722
...\hbox( 6.9444 + .0000)x 20.6944
....\glue .0000
....\hbox( 4.4444 + .0000)x 15.2778
.....\glue .0000 plus 10000000000.0000
.....\hyphenation0
.....\:g a
.....\hyphenation1
.....\glue .0000 plus 10000000000.0000
.....\glue 10.0000
....\glue .0000
....\hbox( 6.9444 + .0000)x 5.4167, glueset .0000
.....\glue .0000 plus 10000000000.0000
.....\hyphenation0
.....\:g b
.....\hyphenation1
.....\glue .0000 plus 10000000000.0000
....\glue .0000
...\glue 5.0556
...\hbox( 6.9444 + .0000)x 20.6944
....\glue .0000
....\hbox( 4.4444 + .0000)x 15.2778, glueset .0000
.....\glue .0000 plus 10000000000.0000
.....\hyphenation0
.....\:g c
.....\hyphenation1
.....\glue .0000 plus 10000000000.0000
.....\glue 10.0000
....\glue .0000
....\hbox( 6.9444 + .0000)x 5.4167
.....\glue .0000 plus 10000000000.0000
.....\hyphenation0
.....\:g d
.....\hyphenation1
.....\glue .0000 plus 10000000000.0000
....\glue .0000
..\hyphenation1
..\glue .0000 plus 100000.0000
.\glue .0000 plus 1.0000
.\glue 1.0000
.\hbox( 6.9444 + .0000)x 353.0000, glueset .0028
..\hbox( .0000 + .0000)x 20.0000
..\:a t
..\:a h
..\:a a
..\:a t
..\glue 3.3333 plus 1.6667 minus 1.1111
..\:a w
..\kern-.2778
..\:a o
..\:a r
..\:a k
..\kern-.2778
..\:a e
..\:a d
..\:a ?
..\glue .0000 plus 100000.0000
.\glue .0000 plus 10000000000.0000
\ctrline #1→\hbox to size{\hskip 0pt plus1000cm minus1000cm #1\hskip 0pt plus1000cm minus1000cm}
#1←\:a\count 0 [1]