Re: [web-devel] Single step debugging a yesod application

3 Nov 2010


      Thanks Alberto, not how I had in mind, but that helps a lot getting where I
need a lot faster.

cheers
----nubis

On Wed, Nov 3, 2010 at 12:06 PM, Alberto G. Corona wrote:
...
Maybe you can break at " u <- get404 uid". Then you can execute
:steplocal once to reach te line you desired.
...
Hi guys,
As I said in another thread, I've been debugging a yesod application
single
stepping through one of the handlers. I'm using ghci built in debugger
and
it's pretty good, but I always fail to set the breakpoint in the right
scope
where I can evaluate the stuff I'm interested in learning more about.
For instance, in the following code I would like to set the debugger on
2010/11/3 Nubis :
the
...
line before "mv <- maybeAuth", in order to :force the values  of (uid,
u).
But even when I set it at the beginnig of the 'mv' line, the scope ends
up
being the entire do block. Which makes sense, but doesn't helpe me solve
my
problem :)
getUserR :: String -> Handler RepHtmlJson
getUserR input = do
    (uid, u) <-
        case readIntegral input of
            Just uid -> debugRunDB $ do
                u <- get404 uid
                mun <- getBy $ UniqueUsernameUser uid
                case mun of
                    Nothing -> return (uid, u)
                    Just (_, Username _ un) ->
                        lift $ redirect RedirectPermanent $ UserR un
            Nothing -> debugRunDB $ do
                mun <- getBy $ UniqueUsername input
                case mun of
                    Nothing -> lift notFound
                    Just (_, Username uid _) -> do
                        u <- get404 uid
                        return (uid, u)
    mv <- maybeAuth
Maybe the problem is that I'm thinking in a too procedural fashion about
do
blocks, or that evaluating those results is kind of paranoid. I'm too
spoiled by REPL's, I would even like to be able to use a REPL that runs
inside runDB for querying models and doing stuff with them interactively.
How do you debug your yesod apps? am I drifting too far away from the
haskell way?
thanks in advance for your comments :)
cheers
----nubis
_______________________________________________
web-devel mailing list
web-devel@haskell.org
http://www.haskell.org/mailman/listinfo/web-devel