(       Title:  Node Space Management for Single and
                Double Lists with Dynamic Strings
         File:  nodespace-pfe.fs
      Version:  1.2.3
       Author:  David N. Williams
      License:  LGPL
Last revision:  November 30, 2004
)
\ Copyright (C) 2000-2002, 2004  David N. Williams
(
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or at your option any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

Please see the file POLITENESS included with this distribution.

ANS Forth compatible except for:
- Case sensitivity.
- REQUIRED loads Forth source if it's not already loaded.
- Assumption that zero does not occur as an address.
- 0$UNUSED uses EMPTY$ and $! from our Dynamic-Strings word
  set.
- "LOADM dstrings" loads the dstrings shared library module in
  pfe.

Uses LOCALS| from the Locals extension word set.

Please see the file NOTATION.
)

s" nodespace.fs" REQUIRED

\ Uncomment *one* of the following two lines: 
  LOADM dstrings            \ for pfe
\ s" dstrings.fs" REQUIRED  \ for ANS compatibility


\ *** EXTENSION WORDS

: 0unused-$nodes  ( -- )
(
Assume the data consists of dstrings.  Set the data in all
unused nodes in the current node space to the empty string.  The
expected use is just after MAKE-NODES, when all nodes are in the
unused chain.  Nevertheless, do nothing if the unused chain is
empty.
)
\  current-nodes IF
\    current-nodes >/node-data @
\    current-nodes >/node-header @
\    current-nodes >last-unused @
\    LOCALS| node /node.header /node.data |
\    BEGIN node WHILE
\      node /node.header +  \ begin data
\      dup /node.data +     \ after data (cell-aligned)
\      swap ( after begin)
\      DO
\        0 i !        \ null is outside string space, so
\        empty$ i $!  \ $! writes over it
\      1 cells +LOOP
\      node @ to node
\    REPEAT
\  THEN ;

  current-nodes IF
    current-nodes >last-unused @
    BEGIN ( node) dup WHILE
      ( node) dup current-nodes >/node-header @ +  \ begin data
      ( begin) dup current-nodes >/node-data @ +   \ after data (cell-aligned)
      swap ( after begin)
      DO
        0 i !        \ null is outside string space, so
        empty$ i $!  \ $! writes over it
      1 cells +LOOP
      ( node) @
    REPEAT ( node) drop
  THEN ;