Via Fatvat's take on HLint I learned about HLint and Neil Mitchell's post on the tool ( Read more... )

Just as a sanity check for Help! Can you run Happstack as a CGI? I made sure your Haskell CGI and FastCGI setup is working.

CGI

-- ghc --make -o CgiPlay.cgi CgiPlay.hs
import Network.CGI

cgiMain :: CGI CGIResult
cgiMain = output "Hello World!"

main :: IO ()
main = runCGI (handleErrors cgiMain)

FastCGI

-- ghc -package fastcgi -threaded --make ( Read more... )

Does anyone already have code for running a Happstack app as a CGi instead of a HTTP Server?

Searching for a CGI adapter or backend to Happstack, I didn't find anything. The documentation mentions you can do it... but it isn't clear if it works out of the box.

I was able to find the happstack-fastcgi package. For fun, I tried converting my app to ( Read more... )

I don't know if I should be proud of myself or not... but my toy application has Seg Faulted ghc :/

I found to suspicious things

• Calling commit on a connection that had already been disconnected
• Trying read an int out of the textual representation of a
  Data.ByteString.Lazy.Char8 and insert it into the database

I'm not quite sure, but fixing those ( Read more... )

It seems like I should be exact as possible with type signatures as I'm learning. For example I was using:

doWeight :: (ServerMonad m) => String -> m Response
which is all fine and good, until I change the String into a Maybe Stats. Then I ran into some compilation errors and I figured it was with my Maybe plumbing or maybe the IO of the database ( Read more... )

I’ve come to know Control.Monad.Trans and liftIO for the first time.

I was trying to glue together Database.HDBC results and a Happstack.Server Response. My method’s which wouldn’t compile looked like
( Read more... )

I'm not much on debuggers and rely on the REPL or println statements to learn what a piece of code is doing (or not doing). A frustration I've been having when learning Haskell, is not knowing where I could use Debug.Trace's trace function in my code. The module Debug.Trace provides two methods.

putTraceMsg :: String -> IO ( Read more... )

Introducing Haskwhal, Missteps of a Narwhal calf...

Hello again... I originally created this journal to track my progress through The Structure and Interpretation of Computer Programs. Until this post, it was named "Eval Scheme, Apply Learnings".

I'm moving on to study Haskell from the excellent book Real World Haskell. A new name is in order... so ( Read more... )

Shame on me... I have been super busy with my new gig. So I finished my independent study on SICP and got my grade back... A boo ya. I turned in a ton of work and it has been a very enlightening and worth while exercise. I really enjoyed working through SICP and STPL. I have not been doing any Lisp stuff since late-April. I will be focusing much ( Read more... )

My friend and colleague Philipp K. Janert is writing a book on gnuplot. I am a technical reviewer and have thoroughly enjoyed the experience so far.


( Read more... )