program helixside(distances, helixsidep, data, output);
(* helixside: distances converted to DNA helical angle.

  Dr. Thomas D. Schneider
  National Institutes of Health
  National Cancer Institute
  Center for Cancer Research Nanobiology Program
  Molecular Information Theory Group
  Frederick, Maryland  21702-1201
  toms@ncifcrf.gov
  permanent email: toms@alum.mit.edu (use only if first address fails)
  http://www.ccrnp.ncifcrf.gov/~toms/

 *)

label 1; (* end of program *)

const
(* begin module version *)
   version = 1.00; (* of helixside.p 2007 Jun 25
2007 Jun 25, 1.00: origin
*)
updateversion = 1.00; (* defines lowest acceptable current parameter file *)
(* end module version *)

(* begin module describe.helixside *)
(*
name
   helixside: distances converted to DNA helical angle.

synopsis
   helixside(distances: in, helixsidep: in, data: out, output: out)

files

   distances:  Distances on DNA

   data:  distances on DNA followed by helical angle.

   helixsidep:  parameters to control the program.  The file must contain the
      following parameters, one per line:

      parameterversion: The version number of the program.  This allows the
         user to be warned if an old parameter file is used.

   output: messages to the user

description

   Convert distances to helical angle.

examples

documentation

see also

author

   Thomas Dana Schneider

bugs

technical notes

*)
(* end module describe.helixside *)

var
   distances, (* file used by this program *)
   helixsidep, (* file used by this program *)
   data: text; (* file used by this program *)

(* begin module halt *)
procedure halt;
(* stop the program.  the procedure performs a goto to the end of the
   program.  you must have a label:
      label 1;
   declared, and also the end of the program must have this label:
      1: end.
   examples are in the module libraries.
   this is the only goto in the delila system. *)
begin
      writeln(output,' program halt.');
      goto 1
end;
(* end module halt version = 'delmod 6.16 84 mar 12 tds/gds'; *)

(* begin module helixside.themain *)
procedure themain(var distances, helixsidep, data: text);
(* the main procedure of the program *)
var
   parameterversion: real; (* parameter version number *)
   d: integer; (* Distance in bases on DNA *)
   angle: real; (* angle on DNA *)
   modulo: real; (* distance modulo twist *)
   twist: real; (* bases per twist of DNA, generally 10.6 *)
begin
   writeln(output,'helixside ',version:4:2);
   reset(helixsidep);
   readln(helixsidep, parameterversion);
   if round(100*parameterversion) < round(100*updateversion) then begin
      writeln(output, 'You have an old parameter file!');
      halt
   end;

   twist := 10.6;

   reset(distances);
   rewrite(data);

   while not eof(distances) do begin
      readln(distances, d);
      modulo := abs(d);
      while modulo > twist do modulo := modulo - twist;
      angle := 360*modulo/twist;
      writeln(data, d:10,' ', angle:10:1);
   end;

end;
(* end module helixside.themain *)

begin
   themain(distances, helixsidep, data);
1: end.