From: rog@vitanuova.com
To: 9fans@cse.psu.edu
Subject: Re: [9fans] OT: small xml parser found!
Date: Thu, 19 Feb 2004 17:15:44 +0000 [thread overview]
Message-ID: <fbb4f5bebcf5822a894afceb2466f92d@vitanuova.com> (raw)
In-Reply-To: <1077206087.1790.18.camel@pc118>
> >> Why isn't Expat suitable?
> >
> > callbacks are horrible.
>
> Reasons?.
>
> Callback-(handler)s are interrupt-(handler)s
> [...]
can i just add this reference:
http://www.codepedia.com/wiki/display.aspx?WikiID=1&pagename=thunks
as an example of a really nasty way (note the machine dependent bit)
of getting around some of the limitations of a callback-based system.
if i was going to use expat, i'd wrap it up with the plan 9 threads
library, so that constructs would arrive on a channel, then at
least things would be marginally more bearable.
but even then, you'd probably want to put a function call interface
around the channel, as otherwise it's really quite awkward
skipping subtrees you don't want to know about.
i wasn't too dissatisfied with the xml(2) interface in inferno,
which looks something like (limbo syntax, i'm afraid):
open: fn(fd: ref Sys->FD): ref Parser;
Parser: adt {
next: fn(p: self ref Parser): ref Item;
down: fn(p: self ref Parser);
up: fn(p: self ref Parser);
};
next() gives you the next item at the current level (nil if we're
at the end of the enclosing block); down() delves into the most recently
returned element, and up() ascends a level.
one advantage of doing it this way is that potentially the parser
can drive how the parsing takes place; the above interface
takes advantage of that by allowing random access into
the XML (you can go back to a place you've previously marked).
next prev parent reply other threads:[~2004-02-19 17:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-17 13:50 steve-simon
2004-02-18 18:17 ` Roger Flores
2004-02-18 20:43 ` rog
2004-02-18 20:42 ` David Tolpin
2004-02-19 15:29 ` rog
2004-02-19 15:27 ` Gorka Guardiola Múzquiz
2004-02-19 15:31 ` boyd, rounin
2004-02-19 16:14 ` Rob Pike
2004-02-19 16:16 ` Rob Pike
2004-02-19 16:18 ` David Tolpin
2004-02-19 16:20 ` boyd, rounin
2004-02-19 15:54 ` John Murdie
2004-02-19 16:14 ` C H Forsyth
2004-02-19 16:24 ` John Murdie
2004-02-19 16:17 ` David Tolpin
2004-02-20 2:36 ` boyd, rounin
2004-02-19 17:15 ` rog [this message]
2004-02-19 17:20 ` David Tolpin
2004-02-19 17:31 ` rog
2004-02-19 17:30 ` David Tolpin
2004-02-19 17:45 ` rog
2004-02-19 17:39 ` C H Forsyth
2004-02-19 15:27 ` David Tolpin
2004-02-19 10:28 ` Roger Flores
2004-02-19 9:59 plan9fans
2004-02-19 10:13 ` David Tolpin
2004-02-19 11:04 ` Dave Lukes
2004-02-19 11:41 ` matt
2004-02-19 12:36 ` Dave Lukes
2004-02-19 13:45 ` C H Forsyth
2004-02-20 8:22 ` Martin C.Atkins
2004-02-19 10:31 plan9fans
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