grap is a pic preprocessor for drawing graphs.

	grap [files] | pic | ...  (mrkos!/usr/bin so far)

.G1
frame  ht e  wid e  top dotted ...
	sets frame around graph to specified ht and wid;
		default ht 3, wid 2
	default mode applies to all four sides;
		you can set top, bot, left or right
		to dotted, dashed, invis, solid independently
label  side   "a label" "as a set of strings" adj
	one line per label, on the four sides.
	default side is bot
	adj is up|down|left|right expr, to shift default position
ticks side inout at optname expr, expr, ...
	put ticks on side at expr, ..., and label with "expr".
	if any expr followed by "...", label tick with "...",
	  and turn off all automatic labels.
	if "..." contains %f's, they will be interpreted as printf
	  formatting instructions for the tick value.
	ticks point in or out according to inout (default out)
	tick iterator: instead of at ..., use from expr to expr by o expr
		where o is optionally +-*/ for additive or multiplicative steps.
		"by" can be omitted, to give steps of size 1.
	if no ticks requested, they are supplied automatically;
	  suppress this with "ticks off".  Automatic ticks normally
	leave a margin of 7% on each side; set this to anything by
		margin = expr
grid side linedesc at optname expr, expr, ...
	draw grids perpendicular (!) to side in style linedesc
	   at expr, ....   Iterators and labels work as with ticks.
coord optname x min, max y min, max log x log y  (x, y literal!)
	set range of coords and optional log scaling on either or both
	overrides computation of data range
	default value of optname is current coordinate system
	(each "coord" defines new coord system)
plot "str" at point (or just "str" at point)
	puts it at the point.  you can add rjust, ljust, above, below after "...".
line from point to point linedesc
	draw line from here to there.
	"arrow" works in place of line.
next optname at point linedesc
	continues plot of data in optname to point;
	default is current
draw optname linedesc "..."
	set mode for next:  use this style from now on,
	and plot "..." at each point (if given)
new optname linedesc "..."
	set mode for next, but disconnect from previous
numberlist
	x y1 y2 y3 ...
	treated as 
		plot bullet at x,y1
		plot bullet at x,y2
		plot bullet at x,y3
	etc., or as next at x,y1 etc., if draw specified.
	abscissae of 1,2,3,... provided if only one input number per line

point
	optname expr, expr
	maps the point to the coordinate system
linedesc
	dot|dash|invis|solid optexpr
define name % whatever %
	macros just like in pic
	There are macros already defined for standard plotting
	symbols like bullet, circle, star, plus: cat /usr/lib/grap.defines,
	which is included if it exists.
var = expr
	operators are = + - * / and ()
	functions are log() and exp() (both base 10!), sin(), cos(), sqrt();
		rand() returns random number on [0,1);
			(you might check RAND_MAX at the top of grap.y)
		max(e,e), min(e,e), int(e).
print expr; print "..."
	as a debugging aid, prints expr or string on the standard error
copy "filename"
	include this file right here
copy thru macro
	pass rest of input (until .G2) through macros,
	treating each field (non-blank, or "...") as an argument.
	"macro" can be the name of a macro previously defined,
	or the body of one in place, like / plot $1 at $2,$3 /
copy thru macro until "string"
	stop copy when input is string (left-justified)
copy "filename" thru macro until "string"
	combinations work too
pic remainder of line
	copied to output with leading blanks removed.
graph Name pic-position
	start a new frame, place it at specified position,
	e.g., graph Thing2 with .sw at Thing1.se + (0.1,0)
	Name is capitalized to keep pic happy.
.anything at beginning of line
	copied untouched
sh X anything X
	passes everything between the X's to the shell;
	as with macros, X may be any character and "anything"
	may include newlines.
# anything after # is a comment
.G2

Order is mostly irrelevant; no category is mandatory.
The simplest graphs are like
	.G1
	1
	2
	.G2
or
	.G1
	1 2
	3 4
	5 6
	.G2
More complicated is like
.G1
frame top invis right invis
coord x 0, 10 y 1, 5 log y
ticks left in at 1 "bottommost tick", 2,3,4,5 "top tick"
ticks bot in from 0 to 10 by 2
label bot "this is a" "silly graph"
label left "left side label" "here"
grid bot dotted at 2,4,6,8
grid left dashed at 2.5

copy thru / plot circle at $1,$2 /
1 1
2 1.5
3 2
4 1.5
10 5
.G2
