\ block words  variable scrvariable recent-buffervariable buffer-mapvariable buffers-basevariable max-buffersvariable blockfilevariable max-blocksvariable bfnamecreate bfname0 bl string blockfile : buffer-addr  ( n -- a ) 1024 * buffers-base @ + ;: buffer-block  ( n -- a ) 2 cells * buffer-map @ + ;: buffer-dirty  ( n -- a ) buffer-block cell+ ; : open-blockfile  ( -- )  blockfile @ 0= if bfname @ count r/w open-file ?fcheck   blockfile ! then ; : update  ( -- ) recent-buffer @ buffer-dirty on ; : save-buffer  ( n -- ) dup buffer-block @ 1024 *  blockfile @ reposition-file ?fcheck dup buffer-addr 1024  blockfile @ write-file ?fcheck buffer-dirty off ; : flush  ( -- ) blockfile @ if max-buffers @ 0 do i   buffer-dirty @ if i save-buffer then loop then ; : empty-buffers  ( -- ) buffer-map @ max-buffers @ 2 cells *   erase ; : next-buffer  ( n1 -- n2 ) 1+ max-buffers @ mod ; : buffer  ( n -- a ) max-buffers @ 0 do recent-buffer @ i +  next-buffer dup buffer-dirty @ 0= if dup recent-buffer ! dup   >r buffer-block ! r> buffer-addr unloop exit then drop loop   recent-buffer @ next-buffer dup save-buffer dup recent-buffer   ! dup >r buffer-block ! r> buffer-addr ; : block  ( n -- a ) open-blockfile  max-buffers @ 0 do dup i buffer-block @ = if drop  i buffer-addr i recent-buffer ! unloop exit then loop dup   1024 * blockfile @ reposition-file ?fcheck buffer dup 1024   blockfile @ read-file ?fcheck drop ; : load  ( n -- ) >r save-input r@ blk ! r> block >r  >in off 1024 >limit ! r> sourcebuf ! interpret restore-input   0= if space s" unable to restore input" type cr abort then  blk @ ?dup if block sourcebuf ! then ; : thru  ( n1 n2 -- ) 1+ swap do i load loop ;: .row  ( n -- ) 2 .r [char] │ emit ; : .blkhdr  ( n -- ) s"   ╭BLOCK: " type 4 u.r   s" ─────────────────────────────────────────────────────╮" type cr ; : list  ( n -- ) base @ >r decimal dup scr ! dup .blkhdr   block 16 0 do i .row dup 64 type [char] │ emit cr 64   + loop drop r> base !   s"   ╰────────────────────────────────────────────────────────────────╯"   type cr ; : .buffers  ( -- ) base @ cr                                      ."   Buffer  Block  Dirty  Address" cr                          ."   ─────────────────────────────" cr                          max-buffers @ 0 do decimal                                       6 spaces i 2 .r 3 spaces i buffer-block @ 4 .r                 4 spaces i buffer-dirty @ if [char] X else [char] - then        emit 3 spaces hex i buffer-addr 8 .r cr                         loop base ! ;                                                                                                                  \ initialization 16 max-buffers !heaptop @ max-buffers @ 1024 * - buffers-base !bfname0 bfname ! 1024 max-blocks !buffers-base @ max-buffers @ 2 cells * - buffer-map !