Re: print hash table to disk and reread in hash table

[Ted Zlatanov]

On Wed, 27 Aug 2008 22:27:47 -0700 (PDT) Xah <xahlee@gmail.com> wrote: 

X> but is there a function or lib to save hashtable to disk? i.e.
X> sometimes called serializing?

No.  It's easy to convert a hashtable to a list, and Emacs makes it easy
to serialize a list, so that's what people do.  I have code in
gnus-registry.el (copied in part from the way Gnus saves its newsrc
file) to do this.  The combination of two easy things is not,
unfortunately, simple anymore.

I like the (puthash ...) approach suggested by Thierry Volpiatto but
it's a lot of function calls for a large hashtable (which the Gnus
registry creates).  So I'm not sure it's the right approach either.

BBDB has a similar problem; it saves vectors instead of lists.

If there's no library for serialization, it should definitely be
written.  Emacs Lisp has only a few basic data types, and not all of
them have to be supported anyhow.

Ted