[Cl-perec-devel] Lots of questions :-)
mihai at bazon.net
Sun Sep 13 10:27:31 UTC 2009
First off, I think you did a great job! CL-perec is very cool, but it's
a pity it's poorly documented and it's hard to get started, so I thought
I'd ask my questions on this list... Please note that I'm new to Lisp
as well, which makes it harder for me to "use the source, Luke". I'd
love to help with some howtos, once I figure out the stuff I'm after.
Questions, in no particular order:
1. I'm defining my own DB package in which I :USE :CL-PEREC. This
introduces some conflicts that can be mitigated by
:shadowing-import-from :cl-perec :set :time. What is the recommended
way, though? Would it be better if I don't :USE :cl-perec and prefix
all names with "cl-perec:"?
2. I have a (defpclass* page) which shows the following warning in SBCL:
; caught STYLE-WARNING:
; defclass* for CL-PEREC:PAGE while its home package is not *package* (#<PACKAGE "DLWEB.DB">)
I can guess that there's a class named "page" in cl-perec?
3. OIDs seem to be randomly generated. Are they generated by cl-perec,
or by Postgres itself? (I haven't use PG in many years so sorry if
4. I have a Perl background and have used various DB-to-Object mappers
(and even wrote my own). Most of them, in Perl, provide an easy way
to "inflate/deflate" columns. For example, if a column is of type
TIMESTAMP (which the DB server returns as a string), when an instance
is retrieved I can make that slot return an object of type DateTime,
which is more comfortable to work with. So in other words, an
automatic conversion happens when a row is fetched from the DB, and
the reverse conversion when it's stored into DB.
Another example is storing hashed passwords in the DB. In Perl I
## and now $user->password is some MD5 of "foobar"
Is there a way to do this with cl-perec?
5. I plan to use cl-perec with hunchentoot for creating sites. One of
the things I commonly did in Perl was to use the same code (and
server) for multiple websites; because they had different data, the
database connection was selected at runtime, depending on the target
domain name of the incoming request. I presume a way to do this in
cl-perec would be to set the value of *database* accordingly on each
request, but since Hunchentoot is multithreaded, would this be safe?
If not, can you recommend a better way?
6. What's with the _ad, _ai, _ap, _dd, _di, _dp views? I can understand
some of them, but for example _ad, _ap, _dd and _dp seem to be
7. How do I define columns of type VARCHAR(255)? It seems wasteful to
use TEXT for every string..
I think that's all. :-) Sorry for the long email and thank you for any
More information about the cl-perec-devel