%title 'AUX BackSpace'
%sbttl 'Introduction'
MODULE aux_bs (	!
		IDENT = '1'
		) =
BEGIN

!
!			  COPYRIGHT (c) 1983 BY
!		Project Software & Development, Inc.
!
! This software is furnished under a license and may be used and  copied
! only  in  accordance  with  the  terms  of  such  license and with the
! inclusion of the above copyright notice.  This software or  any  other
! copies  thereof may not be provided or otherwise made available to any
! other person.  No title to and ownership of  the  software  is  hereby
! transferred.
!
! The information in this software is subject to change  without  notice
! and  should  not  be  construed  as  a commitment by PROJECT SOFTWARE
! AND DEVELOPMENT, INC.
!
! PROJECT SOFTWARE assumes no responsibility for the use or  reliability  
! of its software on equipment which is not supplied by PROJECT SOFTWARE.
!

!++
! FACILITY: AUXiliary Keypad DCL
!
! ABSTRACT: This module returns the address of a descriptor formated to 
!	cause the cursor to 'BackSpace'.  Uses either BackSpaces or the
!	VT100 cursor commands which ever is less.
!
!
! ENVIRONMENT: VMS Native Mode
!
! AUTHOR: M. Erik Husby, CREATION DATE: April 1983
!
! MODIFIED BY:
!
! 	, : VERSION
! 01	- 
!--

!
! TABLE OF CONTENTS:
!

FORWARD ROUTINE
    aux_bs
	;		!

!
! INCLUDE FILES:
!
library
    'sys$library:lib';
Require
    'sys$library:psdi';
Library
    'Auxlib';
!
! MACROS:
!

!
! EQUATED SYMBOLS:
!

!
! OWN STORAGE:
!

!
! EXTERNAL REFERENCES:
!

!EXTERNAL ROUTINE
!	;		!

%sbttl 'AUX_BS'
Global ROUTINE AUX_BS (
    desc	: ref block[,byte],
    count
    ) =	!

!++
! FUNCTIONAL DESCRIPTION:
!	Returns a string formated to cause the cursor to backspace by 'count'
!	spaces.  
!
! FORMAL PARAMETERS:
!
!	desc	: Address of a dynamic descriptor.
!	count	: Number of spaces to backspaces.
!
! IMPLICIT INPUTS:
!
!	NONE
!
! IMPLICIT OUTPUTS:
!
!	NONE
!
! ROUTINE VALUE:
! COMPLETION CODES:
!
!	returns address of DESC.
!
! SIDE EFFECTS:
!
!	NONE
!
!--

    BEGIN
    literal
	bs	= 8
	;
    bind
	backspaces = uplit(rep 5 of byte(bs));
    local_descriptor(backspace,5);
    init_descriptor(backspace,0);
    !
    ! Use up to 5 backspaces otherwise use the cursor backwards command
    if .count leq 5 then
	begin
	backspace_desc[dsc$w_length] = .count;
	ch$move(.count,backspaces,backspace);
	end
    else
	begin
	backspace_desc[dsc$w_length] = 5;
	perform($fao(
	    $descriptor('$[!ZLD'),
	    backspace_desc[dsc$w_length],
	    backspace_desc,
	    .count));
	ch$wchar(escape,ch$ptr(backspace));
	end;
    copy_dx((.desc,backspace_desc));
    return .desc;
    END;			!End of AUX_BS

END				!End of module
ELUDOM