On January 27, 2005 07:38 pm, cbbrowne at ca.afilias.info wrote:
> > On January 27, 2005 03:52 pm, Christopher Browne wrote:
> >> Darcy Buskermolen wrote:
> >> >On January 27, 2005 02:06 pm, Christopher Browne wrote:
> >> And I'll be musing about the merits of maybe using cpp or m4 to do
> >> name/id mappings...  Trying to nearly interchangeably use names or
> >> numbers makes for some thorny problems that "macro rewriting" would make
> >> go away.  I have been warned that I might get shunned by some people if
> >> I try m4...
> >
> > I'll be one of them on that list when it comes to m4.
> >
> > Hmmm.. In all seriousness, how you envisioning the named objects working?
> > Since all of the critical code is implemented in plpgsql, can't we just
> > add a
> > name to the relevent objects, and have the action function check the name
> > column first, and if no matches, assume I passed in an id and cheke the
> > id,
> > and if it's not found then we just exist as normal ? It should be trvial
> > to
> > have slonik parser accept one or the other but not both.   or Am I
> > missing something really simple here?
>
> It's trivial in the parser (well, as "trivial" as Yacc gets).
>
> It's not a problem to apply names to nodes.  Attaching it to INIT CLUSTER
> and STORE NODE was only tricky insofar as the parser.y code and slonik.c
> code separates different parts of the evaluation loop.  Creating a RENAME
> NODE command was similarly relatively easy.  Those are all the operations
> that are easy because they have ID and name right together.
>
> The problem comes as soon as you get past that.  Each of the operators
> that uses node numbers uses that node number to determine which node it's
> supposed to talk to.  If you haven't already got that mapping in memory,
> you wind up needing some sort of "ESP protocol" because the DB you should
> be asking the node number from is the one for which all you have is the
> node name.  Oops.
>
> Conceivably, I could rummage through each of the "admin conninfo"
> instances to see if I can get mappings, but that leaves the further
> entertainment of what to do if events to update the node names are in
> process; I can get ambiguous answers even though they oughtn't be
> ambiguous.
>
> The m4:
>
> define(`node_srvrds005', `1')
> define(`node_srvrds004', `4')
> define(`node_srvrds003', `3')
> define(`node_srvrds007', `78')
> define(`ds501', `501')
>
> causes the following:
>
> node node_srvrds005 admin conninfo 'dsn=foo';
> node node_srvrds004 admin conninfo 'dsn=bar';
> node node_srvrds003 admin conninfo 'dsn=foo';
> node node_srvrds007 admin conninfo 'dsn=foo';
> node ds501 admin conninfo 'dsn=foo';
>
> create cluster	info (id=node_srvrds005);
> store node (id=node_srvrds004, comment='Node on ds004', spool='f');
> store node (id=node_srvrds003, comment='Node on ds003', spool='f');
> store node (id=node_srvrds007, comment='Node on ds007', spool='t');
> store node (id=ds501, comment='Node on ds-501', spool='f');
>
> to expand to...
>
> cbbrowne at wolfe:/usr/share/doc/m4-doc> m4 /tmp/nodes.m4 /tmp/rewrite
>
> node 1 admin conninfo 'dsn=foo';
> node 4 admin conninfo 'dsn=bar';
> node 3 admin conninfo 'dsn=foo';
> node 78 admin conninfo 'dsn=foo';
> node 501 admin conninfo 'dsn=foo';
>
> create cluster  info (id=1);
> store node (id=4, comment='Node on ds004', spool='f');
> store node (id=3, comment='Node on ds003', spool='f');
> store node (id=78, comment='Node on ds007', spool='t');
> store node (id=501, comment='Node on ds-501', spool='f');
>
> For all that m4 is supposedly pretty heinous, I think I can live with that.
>
> Alternatively:
>
> cbbrowne at wolfe:/usr/share/doc/m4-doc> m4 -Dnode_srvrds005=1
> -Dnode_srvrds004=4 -Dnode_srvrds003=3 -Dnode_srvrds007=78 -Dds501=501
> /tmp/rewrite
> node 1 admin conninfo 'dsn=foo';
> node 4 admin conninfo 'dsn=bar';
> node 3 admin conninfo 'dsn=foo';
> node 78 admin conninfo 'dsn=foo';
> node 501 admin conninfo 'dsn=foo';
>
> create cluster  info (id=1);
> store node (id=4, comment='Node on ds004', spool='f');
> store node (id=3, comment='Node on ds003', spool='f');
> store node (id=78, comment='Node on ds007', spool='t');
> store node (id=501, comment='Node on ds-501', spool='f');
>
> With that approach, I can drop the parser changes like I would a dead
> skunk.
>
> I have NO intention of suggesting the use of anything more sophisticated
> than the above sorts of macro rewriting.  None of it will be acceptable to
> "Windows folk," but Jan suggested the thought that "WinFolk" probably
> wouldn't be too excited about slonik in the first place.  Maybe cpp is
> more suitable than m4; I daresay I don't care all that much.

Ok this level of m4 isn't to troublesome to me, I had delusions of sendmail.cf 
looking stuff, and that just really struck fear into my heart.  Though as Jan 
pointed out can m4 even be used on windows ? Ultimately, I'd like to see slon 
be made to run win32 native for those people that are men^H^H^H OS 
challanged.   So I feel It prudent to evaluate the windowsness of m4/cpp 
before chosing one of the other.

>
> That's the 'Thursday nite' view...
And the pre-coffee Friday morning comments...
-- 
Darcy Buskermolen
Wavefire Technologies Corp.
ph: 250.717.0200
fx:  250.763.1759
http://www.wavefire.com