.
\" GLOBAL CONSTANTS "
.
.nr B 3v
.nr T 2v				\"page top margin
.nr M 3n				\"page horizontal margin
.nr W 8.5i-\nMu-\nMu			\"page content width
.nr H (\n(.pu-\nTu-\nBu)		\"max page height
.nr G 2n				\"inter-columns gap
.
.
\" INTERNAL MACROS FOR LAYOUT "
.
\"record the content into a trap
.de C{
.	di C*				\"save text content
.	ll \\n($Wu-\nGu			\"line length column content
..
.
\"place the recorded content into columns, now that we have the height
.de C}
.	br
.	di				\"end C* diversion
.
.	nr $H 0 1v
.	nr $P 0 1u
.
.	mk
.	C?				\"find optimal column height
.	rt
.
.	C0				\"top of first column
.\"	tm Running with C=\\n($c/\\n($C P=\\n($p/\\n($P H=\\n($H h=\\n($h
.	C*				\"print the formatted content
.	sp \\n(.tu			\"consume space until the trap
.
.	po \nMu				\"back to page margin
.	ll \nWu				\"back to full width
.
..
.
\"Trap context:
\" .----------------. .----------------. .----------------.
\" |                | | :::: :::: :::: | | :::: :::: :::: |
\" |                | | :::: :::: :::: | | :::: :::: :::: |
\" | C0:: :::: :::: | | :::: :::: :::: | | :::: :::: :::: |
\" | :::: :::: :::: | | :::: :::: :::: | | :::: :::: :::: |
\" | :::: :::: :::: | | :::: :::: :::: | | ::C1 ::C1 ::C3 |
\" | ::C1 ::C1 ::C2 | | ::C1 ::C1 ::C2 | |                |
\" '----------------' '----------------' '----------------'
.
\"test to print the content to check the height
.de C?
.	C+				\"use more space
.	di _				\"catch output
.	C0				\"top of column
.\"	tm Trying with C=\\n($c/\\n($C P=\\n($p/\\n($P H=\\n($H h=\\n($h
.	C*				\"try to fit the text in this setup
.	br
.	di
.	rm _				\"remove dummy content
.
.	if \\n($o \{\
.		rt			\"back to top
.		C?			\"need more room start over
.	\}
.
.	ch C#				\"remove real trap
.	dt				\"remove diversion trap
..
.
\"set the minimal column width
\" $C	number of column per page width
\" $W	width of each column
.de CW
.	nr $C \nW/\\$1
.	nr $W (\nW+\nG)/\\n($C
..
.
\"increase the space used for extra pages and last columns height
\" $P	number of extra pages
\" $H	Height of the last serie of columns 
.de C+
.	\"note: on first call, $H == $h == 0
.	ie \\n($H>\\n($h \{		\"if rest of page is not enough
.		nr $P \\n($P+1		\"increase extra page count
.		nr $H 3v		\"back to top of next page
.	\}
.	el \{
.		nr $H \\n($H+1v
.	\}
..
.
\"column trap
\" $t	height of column for setting trap
\" $o	is there an overflow? (0=no 1=yes)
\" $c	current column within diversion/trap
\" $p	current number of extra pages spent within diversion/trap
\" $h	height of the page available for our content
.de C#
.	\"pick apropriate trap context
.	ie \\n($p=\\n($P \{\
.		ie \\n($c=\\n($C .C3	\"end of last column of last page
.		el .C1			\"end of some column of last page
.	\}
.	el\{\
.		ie \\n($c=\\n($C .C2	\"end of last column of some page
.		el .C1			\"end of some column of some page
.	\}
.
.	\"page offset
.	ie \\n($p=\\n($P \
.		nr $t \\n($H		\"height to last page height
.	el \
.		nr $t \\n($h		\"height to available height
.
.	\"bump the trap
.	ch C#
.	wh \\n(.du+\\n($tu C#
.	dt \\n(.du+\\n($tu C#
..
.
\"top of article
.de C0
.	nr $o 0				\"no overflow yet
.	nr $c 0 1			\"will be increased by C#{...C+...}
.	nr $p 0 1			\"no extra page spent yet
.	nr $h \nT+\nH-\\n(nl		\"rest of page available
.	mk				\"mark top-of-column
.	C#				\"initial trap setup
.	po \\nMu			\"reset offset
..
.
\"bottom of some column of some page
.de C1
.	nr $c \\n($c+1
.	rt				\"back to top-of-column
.	po +\\n($Wu			\"no effect in diversions
..
.
\"bottom of last column of some page
.de C2
.	nr $c 1
.	nr $p \\n($p+1			\"bump this column's page count
.	bp				\"new page
.	nr $h \\nH			\"a whole empty page just for us
.	po \\nMu			\"reset offset
.	mk
..
.
\"bottom of last column of last page
.de C3
.	nr $o 1				\"column overflow! must start over	
.	po \\nMu
..
.
\"page header
.de HE
.	ps 10p
.	vs 12p
.	po \nMu				\"page margin
.	tl |#1 - 20\n(yr/\n(mo/\n(dy||PAGE \\n%|
.	po 0
\v'-1v'\l'101'
.	po \nMu				\"page margin
..	
.
\"open hook
.de ?{
.	if '\\*?'C{' .C{		\"if want a column layout, open it
.	ds ? C}				\"next step: close column layout
..
.
\"close hook
.de ?}
.	if '\\*?'C}' \{\
.		C}			\"if in a column layout, close it
.		F}			\"if collected footnotes, print them
.	\}
.	ds ? C{				\"next step: open column layout
..
.
\"heading hook
.de ?H
.	if '\\*?'HE' \{\
.		br
.		HE
.	\}
..
.
.de F}
.	F*				\"flush any footnote there was
.	rm F*				\"then remove the associated macro
.	if \\n($F>0 .br
.	nr $F 0 1
..
.
.
\" MS-STYLE MACRO FRONTEND "
.
\"document name
.de TL
.	ad c
.	ps 40p
.	vs 40p
.	ds ? HE
.	wh 0 HE				\"set the trap for subsequent pages
..
.
\"section heading
.de SH
.	?H				\"maybe show a heading separator
.	?}				\"maybe close previous column layout
.	ad l
.	ps 17p
.	vs 17p*3u/2u
.	ft 3				\"bold
..
.
\"paragraph
.de PP
.	?H				\"maybe show a heading separator
.	br
.	ps 10p
.	vs 12p
.	sp 0.5v				\"BUG: does not honor 0.5
.	ft 1
.	ad b
.	?{				\"maybe open a new column layout
..
.
\"footnote start
.de FN
[\\n+($F]				\"add this footnote's reference
.	da F*				\"append this footnote
.	IP [\\n($F]			\"as a numbered paragraph
..
.
\"footnote end
.de FE
.	di
..
.
.
\" SETUP LAYOUT "
.
.CW 30n
.po \nMu
.ll \nWu