Hi, > if param1 > then sp = f1 . f2 . f3 > else sp = f1 . f3
If you have many situations like these, i.e. where one or several components are conditional, you can define a function when True f = f when False _ = id And now you can define sp like this: sp = f1 . when param1 f2 . f3 Regards, Jonas On 24 August 2011 14:35, dokondr <[email protected]> wrote: > Hi, > What is the Haskell way to compose functions in run-time? > Depending on configuration parameters I need to be able to compose function > in several ways without recompilation. > When program starts it reads configuration parameters from a text file. For > example, I have three functions, f1, f2, f3, each doing some string > processing. I need to support two configurations of string processors : > > if param1 > then sp = f1 . f2 . f3 > else sp = f1 . f3 > > I'd like to avoid 'if' somehow and instead use some declarative way to > specify code to run in external configuration file. In other words I need > some easy tools to create mini DSLs without all the efforts usually involved > with implementing full-blown DSL. > > Thanks, > Dmitri > > > > > > > _______________________________________________ > Haskell-Cafe mailing list > [email protected] > http://www.haskell.org/mailman/listinfo/haskell-cafe > > _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
