Menu.pas

Un article de Wikipedia.

Génération de menus

// librairie de creation de menus
//
// methodes
//  initmenu(var m:menu)
//  titlemenu(var m:menu;t:string)
//  addmenuitem(var m:menu;e:string)
//  selectmenu(m:menu):integer
//  sizemenu(var m:menu):integer
//
// definitions a inclure
// {$i PalmAPI2.pas}
const maxmenu = 10;
type
 plistitem = ^listitem;
 listitem = record
  etiquette : string;
  next : plistitem;
 end;
 menu = record
  title : string;
  next : plistitem;
 end;
//var m : menu;
function sizemenu(var m:menu):integer;
var tm:plistitem;
 count:integer;
begin
 if m.next = nil then
  sizemenu := 0
 else
 begin
  tm := m.next;
  count:=1;
  while tm^.next <> nil do
  begin
   count:=count+1;
   tm := tm^.next;
  end;
  sizemenu := count;
 end;
end;
procedure initmenu(var m:menu);
begin
 m.title := '';
 m.next := nil;
end;
procedure titlemenu(var m:menu;t:string);
begin
 m.title := t;
end;
procedure addmenuitem(var m:menu;e:string);
var tm:plistitem;
begin
 if m.next = nil then
 begin
  new(m.next);
  with m.next^ do
  begin
   etiquette := e;
   next := nil;
  end;
 end
 else
 begin
  tm:=m.next;
  while tm^.next <> nil do
   tm := tm^.next;
  new(tm^.next);
  with tm^.next^ do
  begin
   etiquette := e;
   next := nil;
  end;
 end;
end;
function selectmenu(m:menu):integer;
var tm:plistitem;
 page,count,n,maxpages,sel,selecteditem:integer;
 selection:set of 1..20;
 navigation:set of 'A'..'z';
 s:string;
 quit:boolean;
 maxmenuitems:integer;
function itemnumber(n,max:integer):integer;
begin
 itemnumber:=((n-1) mod max)+1;
end;
begin
 //bug dans la multiplication de constante
 maxmenuitems:=maxmenu;
 page:=0;
 quit:=false;
 selecteditem:=0;
 maxpages:=(sizemenu(m)-1) div maxmenuitems;
 repeat
 clrscr;
 count:=1;
 selection:=[];
 navigation:=['q','Q'];
 writeln;
 writeln(' ':5,m.title);
 write(' ':5);
 for n:=1 to length(m.title) do
 begin
  write('-');
 end;
 writeln;
 writeln;
 if m.next <> nil then
 begin
  tm:=m.next;
  while tm^.next <> nil do
  begin
   if (count > maxmenuitems*page) and (count <= maxmenuitems*(page+1)) then
   begin
    writeln(itemnumber(count,maxmenuitems):3,'. ',tm^.etiquette);
    selection:=selection+[itemnumber(count,maxmenuitems)];
   end;
   tm:=tm^.next;
   count:=count+1;
  end;
  if (count > maxmenuitems*page) and (count <= maxmenuitems*(page+1)) then
  begin
   writeln(itemnumber(count,maxmenuitems):3,'. ',tm^.etiquette);
   selection:=selection+[itemnumber(count,maxmenuitems)];
  end;
 end;
 writeln;
 if page > 0 then
 begin
  writeln('p':3,'. Precedent');
  navigation:=navigation+['p','P'];
 end;
 if page < maxpages then
 begin
  writeln('s':3,'. Suivant');
  navigation:=navigation+['s','S'];
 end;
 writeln('q':3,'. Quitter');
 writeln;
 write(' ':5,'Selection : ');
 read(s);
 if 'p' in navigation then
  if (s = 'p') or (s = 'P') then
   page:=page-1;
 if 's' in navigation then
  if (s = 's') or (s = 'S') then
   page:=page+1;
 if (s = 'q') or (s = 'Q') then
   quit:=true;
 sel:=StrAtoI(s);
 if sel in selection then
 begin
  selecteditem:=sel+maxmenuitems*page;
  quit:=true;
 end;
 until quit = true;
 selectmenu:=selecteditem;
end;