Consider that
interface PasswordStore {
void store(Path path, String secret, Map metadata);
}
is identical to
void store (PasswordStore store, Path path, String secret, Map metadata)
or
store :: PasswordStore -> Path -> secret -> MetaData -> IO ()
So, you can treat PasswordStore as a pure data structure (that has things
like connection details) and just define functions that use it. I wouldn't
worry about grouping the functions together.(*) I'm going to assume you
don't really need an actual interface, but if you did, you could
investigate typeclasses.
Julian.
(*) In general terms, the only reason to group functions together is to
enforce laws that relate the behaviours together e.g. that you can retrieve
something you stored.
On 4 January 2015 at 11:14, Thomas Koch
Hi,
I'm writing a password manager that implements a dbus-api using the dbus[1] package. I'd like to separate the code that implements from the dbus api from the code that stores and retrieves the secrets (passwords). In Java I'd use an interface, e.g.:
interface PasswordStore { void store(Path path, String secret, Map metadata); (String secret, Map metadata) retrieve(Path path); (String secret, Map metadata) search(Map criteria); }
And the dbus-api would export this interface:
dbusClient.export(PasswordStore store)
What would be a Haskell way to do the same? My only idea is to define a record:
data PasswordStore { store :: Path -> Secret -> MetaData -> IO () , retrieve :: Path -> IO (Secret, MetaData) , search :: Criteria -> IO (Secret, MetaData) }
Thank you for any suggestions! Thomas Koch
[1] http://hackage.haskell.org/package/dbus-0.10.9 _______________________________________________ Beginners mailing list Beginners@haskell.org http://www.haskell.org/mailman/listinfo/beginners