[pclasses-devel] an ideal deps tree

[stephan b. <st...@s1...>]

Okay, this point is really bugging me, and i couldn't sleep...

Please understand: i'm not complaining to anyone here, i'm just trying 
to express how important a solid dependencies model is on flexible 
software. At the end of this mail i detail the short list of things we 
need to do to reach a "well-dependencied" tree.

i've been playing around on paper, and i've found a deps tree which:

a) i really like.

b) is extremely close to what we have now.

Unfortunately, i can't copy my drawing into the mail. i will try to 
express it in "flat form" here.

Assumption #0: Core depends on no other P Modules. Period.

Assumption #1: all modules depend on the Core. This is a fair 
assumption, even if it isn't 100% technically true.

Assumption #2: all modules except Core depend on Util. This is almost 
100% true, but not quite.

Assumption #3: all modules depend on themselves. Sounds silly, but it is 
significant.

When i write:
	A ==> B

That means module A has a direct dep on module B. A uses B. Thus:

	A <==> B

is circular, and therefore Evil.

Now, here are the deps as i BELIEVE them to be currently:

(Reminder: Unicode and s11n's core are handled by Assumptions #1 and 
#2.)

System ==> Unicode
System ==> IO
Net ==> IO
Net <==> System (only timeout.h)
SIO ==> (s11n and s11n::io)
s11n::io ==> s11n (s11n 
Plugins ===> may freely dep on any P module

That's all fairly good - i'm fairly happy with that :). Now comes the 
problem:

Util ==> IO (only because of the Prefs' throw IOError)
Util ==> System (only classes ThreadPool and WorkerQueue)

That means that ALL other modules have a dep on IO and System. Nothing 
is standalone :(. Nothing!

Actually, we're much closer than i thought! i thought Unicode had a dep 
on Util, and that IO had a dep on System, but this does not appear to 
be the case (after some grepping) :).

So, here is what i propose we do:

a) Change Util::Prefs to throw Error instead of IOError. IMO this is a 
much better solution for Prefs' API, anyway.

b) Move the thread-related Util stuff into Thread (==> System) or into 
System.

c) Is Net's dep on timeout.h really significant? This seems like an 
extremely low-level detail which we could overlook?

If nobody objects, i will happily do (a) and (b).

"i await your command..."

(And now i'm really going to bed...)

-- 
----- st...@s1...   http://s11n.net
"...pleasure is a grace and is not obedient to the commands
of the will." -- Alan W. Watts