pberck@kub.nl (Peter Berck) (05/03/91)
How can a save a hash-table to disk? I tried the obvious
(print *hash-table* my-stream) but this didn't work. It would just
save "#<hash-table 0017de20>" to disk. (It contains about 10000
entries).
Should I use something like (maphash ...) and save all key-value pairs
to disk? That will probably cost more time than generating it.
thanx,
-peter
------------------------------------------------------------------------
pberck@kub.nl kubvx1::berckp
Back to Lisp Top Levelpab@lucid.com (Peter Benson) (05/03/91)
There is a hack that works (I think) in lucid common lisp.
That is make a file with just
(in-package :whatever)
(setq *hash-table* '#.*hash-table*)
and then compile that file.
I don't know if this is required to work by CLtL. Any x3j13 people know if
this is clarified.
The other alternative is to generate a source file like:
(let ((hash-table (make-hash-table)))
(dolist (pair
'#.(let ((list nil))
(maphash #'(lambda (k v)
(push (cons k v) list))
*hash-table*)
list))
(setf (gethash (car pair) hash-table) (cdr pair)))
(setq *hash-table* hash-table))
and compile that file.
This will work as long as the keys and values in the hash table are things
that can be put in a compiled file. Depending on how fast the binary file
loader is it may be faster than just putting the values in a file. The
other advantage is that you don't have to worry about whether all the
objects in the hash table print readably.
-ptr-
pab@lucid.commoore%defmacro.utah.edu@cs.utah.edu (Tim Moore) (05/04/91)
In article <PAB.91May3123317@challenger.lucid.com> pab@lucid.com (Peter Benson) writes: >There is a hack that works (I think) in lucid common lisp. >That is make a file with just > >(in-package :whatever) >(setq *hash-table* '#.*hash-table*) > >and then compile that file. >I don't know if this is required to work by CLtL. Any x3j13 people know if >this is clarified. One problem is that compiled constants are immutable, which means you couldn't (portably) add or delete any entries in the hash table when you loaded the file back in. -- Tim Moore moore@cs.utah.edu {bellcore,hplabs}!utah-cs!moore "Ah, youth. Ah, statute of limitations." -John Waters
mdb@zero.arc.ab.ca (Mark Brinsmead) (05/06/91)
In article <1991May3.134834.26515@hellgate.utah.edu>, moore%defmacro.utah.edu@cs.utah.edu (Tim Moore) writes: |> In article <PAB.91May3123317@challenger.lucid.com> pab@lucid.com (Peter Benson) writes: |> >There is a hack that works (I think) in lucid common lisp. |> >That is make a file with just |> > |> >(in-package :whatever) |> >(setq *hash-table* '#.*hash-table*) |> > |> >and then compile that file. |> >I don't know if this is required to work by CLtL. Any x3j13 people know if |> >this is clarified. |> |> One problem is that compiled constants are immutable, which means you |> couldn't (portably) add or delete any entries in the hash table when |> you loaded the file back in. |> There are *portable* ways to get around this. I have already "advertised" a CLOS-based package for saving common-lisp and CLOS objects by producing (sometimes large) source files which will re-create them. It is possible to preserve eq-ness throughout arbitrary structures, and to save (and restore) structures with arbitrary circularity. The package will save objects of almost any type (I still haven't figured out how to do defstruct's portably) including hash-tables, and CLOS instances. Its biggest problem is an occasional tendency to save *more* than you want it to! Unfortunately, I am still awaiting clearance to release the source code. When (if) I get it, the code will be released on comp.lang.clos. -- Mark Brinsmead Alberta Research Council Calgary Alberta Canada. email: mdb@arcsun.arc.ab.ca telephone: (403) 297-2600
jpalmucc@bbn.com (Jeff Palmucci) (05/09/91)
pberck@kub.nl (Peter Berck) writes: >How can a save a hash-table to disk? I tried the obvious >(print *hash-table* my-stream) but this didn't work. It would just >save "#<hash-table 0017de20>" to disk. (It contains about 10000 >entries). In Lucid, you can (princ "(Setq *hash-table* #.*hash-table*)" my-stream) and then (compile-file my-file). The binary version will have an image of the hash table. With symbolics, use sys:dump-forms-to-file. Jeff