\ BOOKMARK.SEQ  Mark your place in a file, to come back to.

comment:

  Jerry Modrow had a bright idea that it would be nice to be able to
mark your place in a file, such that you could go back to that place
at a later time after having done a VIEW.  This is an implimentation
of that concept.

comment;

5 constant #marks

create markhandles      #marks b/hcb * allot
create marklines        #marks 2* allot

: clr_marks     ( --- )                 \ Clear the Book Marks
                markhandles #marks 0
                do      dup clr-hcb b/hcb +
                loop    drop
                marklines #marks 2* erase ;

clr_marks                               \ Initialize Book Marks to empty

: mark_init     ( --- )                 \ Clear Book Marks at Cold Start time
                defers initstuff
                clr_marks ;

' mark_init is initstuff

: makemarkset   ( n1 --- )              \ Creates the Set Mark words
                dup #marks >= abort" No more room to create marks!"
                create ,
                does> @ dup 2* marklines + loadline @ swap !
                b/hcb * markhandles + shndl @ swap b/hcb cmove ;

0 makemarkset m1                        \ Three Book Marks for now
1 makemarkset m2
2 makemarkset m3
3 makemarkset m4
4 makemarkset m5

: returntomark  ( n1 --- )              \ Creates the Back to Mark words
                dup #marks >= abort" No more room to create marks!"
                create ,
                does> @ dup b/hcb * markhandles +
                dup >hndle @ 0 < abort" No Mark to return to."
                $hopen abort" Error going back to Mark!"
                2* marklines + @ loadline ! ;

0 returntomark bm1                      \ Three Back to Mark words
1 returntomark bm2
2 returntomark bm3
3 returntomark bm4
4 returntomark bm5