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128 var
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end;
refhead = 'head;
head = record
next : refhead;
first : reflink;
end;
maxposition, minposition, width, w, charp : integer;
startposition, beginposition, endposition : integer;
pagewidth, p, i, j, stemlength, vertnodelength : integer;
endloop : boolean;
line: packed array [1 •• 512) of char;
L, oldL : ref1ink;
lines, slines, H, D : refhead;
procedure cout (c : char);
(* Cout places a character in the line buffer at the
current character position. The pointer charp is
incremented by this action to reflect the change. *)
begin (* Cout *)
charp := charp + 1;
line[charp) := c;
end; (* Cout *)
procedure cdump;
(* Cdump dumps all characters that have accumulated in
the line buffer. No characters are omitted and no
cr-lf is appended. *)
begin (* Cdump *)
if charp > 0 then for charp := 1 to charp do
write (treefile,line[charp);
charp := 0;
end; (* Cdump *)
procedure ctrim;
(* Ctrim dumps all characters that have accumulated in
the line buffer with trailing spaces removed. A
WRITELN is used to end the line. *)
begin (* Ctrim *)
while (charp > 0) and (line[charp) = ' ') do
charp := charp - 1;
if charp > 0 then for charp := 1 to charp do
write (treefile,line[charp);
charp := 0;
writeln (treefile);
end; (* Ctrim *)
function position (N : nodeptr; var H : refhead; pos : integer)
: refl ink;
(* Position is a recursive function that positions all the
nodes of the tree on the print page. In doing so, it
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var
constructs an auxiliary data structure that is connected
by line number along the edge and position from left to
right. In addition, it stores some of the original tree
connections for a~c printing. *)
over, lastover, nodecount
Nlower : nodeptr;
L, left, right : reflink;
needright : boolean;
integer;
begin (* position *)
if N = nil then (* Be defensive about illegal nodes. *)
position := nil
else
begin (* Create a new node in our tree. *)
new (L);
position := L;
L' • pnod e : = N;
LA.ustem := false;
if H = nil then
begin (* A new line has been reached. *)
new (H);
H·.next := nil;
L·.next := nil;
end
else
begin (* Shift position if conflicting. *)
L·.next := H·.first;
if H·.first·:po~ < ~os + 2 then
pos := H .flrst .pos - 2;
end;
H·.first := L;
nodecount := 0;
over := 1;
repeat (* Count the number of lower nodes. *)"
Nlower : = lowerr,ode (N ,over) ;
if ((Nlower N) and (Nlower nil» then
nodecouY'-;': := nodecount + 1;
over := 0"; ,.. + 1;
until Nlower = N;
if nodecount > ~ then
begin (* There are lower nodes, loop to position. *)
L·.lstem := true;
lastover := nodecount - 1;
nodecount := over;
over := - lastover;
.....
'"
00
.....
needright := true;
repeat (* Recursively evaluate lower positions. *)
repeat (* Find one that is non-nil. *) ~
if nodecount > 0 then :;:
Nlower := lowernode (N,nodecount)
else
Nlower := N;
nodecount := nodecount - 1;
until Nlower nil;
if Nlower N then
begin
left :=
pOSition (N10wer, HA.next, pos + over);