GHC as a library - getting output from GHCI

[Mads Lindstrøm]

Hi Pepe

I would have liked something cross-platform.

Also, if stmt contains an error, wrapStmt will not be evaluated, and the
resulting error is written to standard output or maybe to standard
error. Whichever way, I am back to the same problem.


Greetings,

Mads Lindstrøm

> I believe that the trick is to wrap your stmt in a IO handler that  
> captures stdout and returns it together with the value of your stmt.  
> That is, something with a type:
> 
> wrapStmt :: IO a -> IO (a,String)
> 
> It should be easy to implement wrapStmt using System.Posix.Process.  
> Then you just define
> 
> runStmt' session stmt = runStmt session ("wrapStmt $ " ++ stmt)
> 
> Good Luck!
> 
> On 04/05/2007, at 18:04, Mads Lindstrøm wrote:
> 
> > Hi
> >
> > I am trying to use GHC as a library (see
> > http://haskell.org/haskellwiki/GHC/As_a_library ). I want to get  
> > all the
> > output from an interactive session and put in a GUI. This
> > http://haskell.org/sitewiki/images/5/51/Interactive.hs seemed to be a
> > nice starting point.
> >
> > However, the result of:
> >
> > GHC.runStmt session stmt
> >
> > does not include the output of evaluating the statement (stmt above) -
> > just the names of bound names. That is if stmt eqauls "3 + 5" then
> > GHC.runStmt do not return a string equaling "8", but just the "it"- 
> > name
> > (which is bound to 8).
> >
> > The output is printed to standard output :( And I do not see and easy
> > way to get hold of it. The only way I see, is having the GUI in one
> > process and "GHC as a library" in another process.
> >
> > Do anybody know of an easy way to get hold of the output from "GHC  
> > as a
> > library" - the output currently printed to standard output?
> >
> >
> > Greetings,
> >
> > Mads Lindstrøm
> >
> > _______________________________________________
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> > Glasgow-haskell-users at haskell.org
> > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
> 
>