!!
!!  Module Name                 :  EVE_SORT
!!
!!  Original Request Number     : 
!!      System Designation      : Sorts a range or buffer. Select ascending
!!      Module Description      : or descending order by relationship of
!!                              : beginning and ending of a range.
!!                              : 
!!      Original Programmer     : UCS_KAS@SHSU.BITNET
!!
!!      Date Approved           : 14-MAY-1989
!!
!!      Files open for Input    : 
!!      Files open for Output   : 
!!      Modules Referenced      : 
!!
procedure eve_sort
local   sort_array,
        sort_index,
        next_index,
        range_sort,
        end_select,
        reverse_order,
        top_Sel,
        bottom_sel;
on_error
    [OTHERWISE]:
endon_error;
sort_array := create_array;
range_sort := EVE$X_SELECT_POSITION <> 0;
if range_sort then
    reverse_order := EVE$X_SELECT_POSITION > mark(free_cursor);
else
    reverse_order := 0;
endif;
if range_sort then
    if reverse_order then
        top_sel := mark(none);              ! mark top
        position(eve$x_select_position);    ! goto bottom
        bottom_Sel := mark(none);           ! mark bottom
        position(top_sel);                  ! goto top
        eve$x_select_position := 0;         ! clear select
        eve$x_select_position := select(reverse);   ! select from top
        position(bottom_sel);               ! goto bottom
    endif;
    end_select := mark(none);
    position(EVE$X_SELECT_POSITION);
    position(line_begin);
else
    position(beginning_of(current_buffer));
endif;

loop
    if range_sort then
        exitif mark(none) >= end_select;
    else
        exitif mark(none) >= end_of(current_buffer);
    endif;
    next_index := sort_array{current_line};
    if next_index = tpu$k_unspecified then
        sort_array{current_line} := 1;
    else
        sort_array{current_line} := next_index + 1;
    endif;
    move_vertical(1);
endloop;
if range_sort then
    erase(select_range);
else
    erase(current_buffer);
endif;
if reverse_order then
    sort_index := get_info(sort_array,"last");
else
    sort_index := get_info(sort_array,"first");
endif;
loop
    exitif sort_index = tpu$k_unspecified;
    loop
        exitif sort_array{sort_index} = 0;
        copy_text(sort_index);
        split_line;
        sort_array{sort_index} := sort_array{sort_index} - 1;
    endloop;
    if reverse_order then
        sort_index  := get_info(sort_array,"previous");
    else
        sort_index  := get_info(sort_array,"next");
    endif;
endloop;
erase_line;
if range_sort then
    EVE$X_SELECT_POSITION := 0;
endif;
endprocedure