Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!unmvax!ncar!ames!amdcad!sun!pitstop!sundc!seismo!uunet!mcvax!ukc!etive!aipna!jeff
From: jeff@aipna.ed.ac.uk (Jeff Dalton)
Newsgroups: comp.lang.lisp
Subject: Re: The best way to save data
Keywords: save, load, lisp, Database
Message-ID: <414@aipna.ed.ac.uk>
Date: 18 Dec 88 17:41:09 GMT
References: <627@wucs1.wustl.edu> <7943@orstcs.CS.ORST.EDU>
Reply-To: jeff@uk.ac.ed.aipna.UUCP (Jeff Dalton)
Organization: Dept. of AI, Edinburgh, UK
Lines: 23

In article <7943@orstcs.CS.ORST.EDU> ruffwork@urania.CS.ORST.EDU (Ritchey Ruff) writes:
	    > (setq *foo* <some huge data structure>)
	    (...)
	    > (compile-file "foo")

    Of course this is not human readable, and the output will
    only read back into the lisp it was compiled from, but if
    you are like me and need to dump 2 to 10 Meg structures to
    files then read them back in this saves 2 to 5 minutes of
    load time...

The problem with this trick is that it's not guaranteed to work
in every Common Lisp.  You can do it, but some CL's (e.g., KCL)
use PRINT and READ to dump and load data in compiled files, so
you won't necessarily save anything over using PRINT and READ
yourself.  And even if CL changes on the way to standardization
to rule out using READ to load compiled data, there's still
no guarantee that the operation will be much faster than READ.

BTW, this suggests that the dump/load used for compiled data
should be available directly, without compiling a file.  But
it's quite common in Common Lisp for such operations (where
you know they're there and want to get at them) to be unavailable.