File r37/packages/rlisp88/records.red artifact 116b98ffdd part of check-in b5833487d7

module records; % A record package for RLISP using MSTRUCT.

% Author:  Bruce Florman.

% Copyright:  (c) 1989 The RAND Corporation.  All rights reserved.

% Revision History:
%  01/26/89 BAF -- Added this file header.
%       Sat Apr 24 12:38:32 1993 - Remove non-RLISP'88 functions (first,
%           etc.).

% BothTimes Load MSTRUCT;

%-----------------------------------------------------------------------
%      RECORD Declaration
%-----------------------------------------------------------------------

Expr PROCEDURE RecordStat();
% RECORD <struct-name>
%  { /* <annotation> */ }
%  { WITH <field> := <expression> { , <field> := <expression> }... }
%  { HAS <option> { , <option> }... } ;
   begin scalar f, stat;
      f := FlagP('HAS,'DELIM);
      Flag('(HAS),'DELIM);
      stat := Errorset('(RecordStat1),NIL,nil);
      if not f then RemFlag('(HAS),'DELIM);
      if errorp stat THEN while cursym!* neq '!*SEMICOL!* do scan()
       else return car stat
   end;

expr procedure recordstat1();
   begin scalar structname, annotation, fields, options;
      structname := Scan();
      if not idp structname then symerr('RECORD, T);
      if eqcar(scan(), '!*COMMENT!*) then
	 <<annotation := cadr cursym!*; Scan()>>;
       if cursym!* eq 'WITH then fields := remcomma xread nil;
       if cursym!* eq 'HAS then options := remcomma xread NIL;
       if cursym!* eq '!*SEMICOL!* then
	 return {'RECORD, structname, annotation, fields, options}
       else symerr('RECORD, T)
   END;

Put('RECORD,'STAT,'RecordStat);

expr procedure formrecord(u, vars, mode);
apply(form_function, cdr u)
where form_function = 
  function(lambda(record_name, annotation, fields, options);
     begin scalar structspec, fieldspecs, constructor, form;
       structspec := Form_structure_specification(record_name, options);
       fieldspecs := Form_field_specifications(fields);
       constructor := Cdr Atsoc('CONSTRUCTOR,
                                Get_defstruct_options structspec);
       form := {NIL};
       tconc(form, 'PROGN);
      if constructor then
	 << tconc(form,
                  {'put, mkquote constructor,
                         '(QUOTE FORMFN),
			 '(QUOTE FORM_RECORD_CONSTRUCTOR)});
             put(constructor, 'FORMFN, 'FORM_RECORD_CONSTRUCTOR) >>;
      if annotation then
	 tconc(form, {'PUT, mkquote record_name,
                            '(QUOTE ANNOTATION),
                            annotation});
      tconc(form, 'DEFSTRUCT . structspec . fieldspecs);
      return Car form 
      end);

Put('RECORD, 'FORMFN, 'FormRecord);

expr procedure tconc(ptr,elem);
   % ACONC with pointer to end of list.  Ptr is (list . last CDR of
   % list).  Returns updated Ptr.  Ptr should be initialized to
   % (NIL . NIL) before calling the first time.
   <<elem := list elem;
     if not pairp ptr then elem . elem
      else if null cdr ptr then rplaca(rplacd(ptr,elem),elem)
      else <<rplacd(cdr ptr,elem); rplacd(ptr,elem)>>>>;

expr procedure Form_structure_specification(record_name, options);
append(defaults,
       for each entry in options
            collect if atom entry then entry
		    else if eqcar(entry, 'NO) and length entry=2 then
                         {cadr entry, NIL}
		    else if car entry eq 'EQUAL and length entry=3 then
                         {cadr entry, caddr entry}
		    else error(0, {"Bad RECORD option:", entry}))
     where defaults = {record_name,{'CONSTRUCTOR, record_name},
		       'predicate};

expr procedure form_field_specifications field_list;
for each entry in field_list
    join
       if eqcar(entry, 'SETQ)
	 then {{cadr(entry), form1(caddr entry, NIL, 'SYMBOLIC)}}
	else nil;

expr procedure form_record_constructor(u, vars, mode);
begin scalar constructor, arglist;
  constructor := car u;
  arglist := {NIL};
  for each arg in cdr u
    do if eqcar(arg, 'SETQ) then
	   << tconc(arglist, cadr arg);
	      tconc(arglist, form1(caddr arg, vars, mode)) >>
       else rederr {arg, "is not a proper initialization form for",
                    constructor};
  return constructor . car arglist;
end;

endmodule;

end;