21:27:00 <grafa123824> guys I am trying to setup a helloworld example of happs
21:27:11 <grafa123824> could somebody point me to a working tutorial
21:27:33 <grafa123824> http://www.haskell.org/haskellwiki/HAppS_tutorial2
21:27:34 <grafa123824> I tried this
21:28:19 <grafa123824> but I keep on getting could not find module HAppS.Server
21:28:33 <grafa123824> I know I has successfully installed 'happstack' from cabal
21:28:36 <grafa123824> any thoughts
21:29:42 <aavogt> because Happstack puts the modules in the Happstack. namespace
21:31:47 <aavogt> grafa123824: did you check the other ones listed here: http://happstack.com/tutorials.html
21:54:06 <grafa123824> aavogt: that's where I got the link I pasted
21:54:20 <grafa123824> it's the second one listed there
21:54:27 <aavogt> well the tutorial.happstack.com one is pretty good
21:55:20 <grafa123824> I am guessing I might be missing the HAppS package
21:55:28 <grafa123824> but I did do cabal install happstack
21:55:58 <grafa123824> should that include the package that the tutorial imports? import HAppS.Server
21:56:49 <aavogt> no, the tutorial is old... development on happs continues on happstack
23:01:24 <aavogt> I have narrowed down a call to Prelude.undefined in my happstack using +RTS -xc : http://hpaste.org/fastcgi/hpaste.fcgi/view?id=21130#a21130
23:02:13 <aavogt> this is after commenting out the use of catchError in happstack-server-0.4.1
23:03:29 <stepcut> nice!
23:04:02 <aavogt> stepcut: do you see how to fix this though?
23:05:45 <stepcut> don't call undefined?
23:05:51 <aavogt> I don't
23:06:20 <aavogt> this is the puzzling thing
23:08:10 <sm> I wouldn't take -xc output as 100% accurate
23:12:20 <stepcut> aavogt: what is the problem?
23:13:43 <aavogt> stepcut: my app says something calls Prelude.undefined instead of doing the right thing
23:14:01 <stepcut> aavogt: when?
23:14:29 <aavogt> when I submit a request...
23:14:47 <stepcut> are you using libraries besides happstack?
23:14:53 <aavogt> yes
23:15:01 <stepcut> could one of those be calling undefined?
23:15:12 <aavogt> is the -xc output to be trusted?
23:15:23 <stepcut> doubt it
23:16:07 <stepcut> it probably just tells you that it was in the withTimeOutMaybe function when a lazy value was finally forced and discovered to be 'undefined'
23:19:39 <aavogt> stepcut: how do you suggest I find this occurence of undefined then?
23:20:51 <aavogt> basically I have an IntMap in an mvar which I look to retrieve some cached results
23:48:30 <stepcut> aavogt: eliminate code until you find the part that causes the error?
23:50:36 <aavogt> well the undefined isn't litterally in my code
23:51:16 <aavogt> but maybe I accidentally managed to use some function defined using undefined somewhere else like hlist
23:52:01 <stepcut> right
23:52:28 <stepcut> happstack does use undefined some places, but not in ways that should actually be problematic
23:52:31 <aavogt> though recompiling that after replacing all undefineds with an appropriate error message doesn't seem to do the trick
23:52:38 <stepcut> mostly things like, typeOf (undefined :: a)
23:53:11 <aavogt> yeah, those shouldn't fail
23:53:25 <stepcut> if you print the retrieved cached value, does that cause an undefined?
23:53:33 <aavogt> all my typeable instances are defined
23:53:51 <aavogt> actually running the IO that retrieves the cached value triggers it
23:55:24 <stepcut> does that IO use happstack?
23:56:03 <stepcut> gtg, meeting time
23:57:11 <aavogt> nope
23:59:34 <stepcut> anyway, I don't know any secret tricks. You just got to eliminate possibilities until you find the problem :)