Aliases in Haskell/GHCI

Question

Is it possible to set aliases in the ghci.conf file?

For example I have alias sbh='cd Desktop/Sandbox/Haskell' in bash.bashrc which lets me quickly jump to the specified folder. Is the same thing possible in ghci by putting an alias in the ghci.conf file?

I already have a few commands in ghci.conf but I would like to have multiple aliases set up to jump to folder locations without having to use :cd home/sandbox/foo/bar all of the time. I cant find anything on google so either its never been considered before or am just missing something very simple.

Answer 1

The :def command can do this:

:def sbh const $ return ":cd Desktop/Sandbox/Haskell"

As you can see it is a little more complicated than just giving a substitution string: It takes a Haskell function of type String -> IO String which the newly defined command applies to its argument string to calculate new commands to run.

Then in GHCI :sbh to invoke.

Answer 2

GHCI macros should give you what you're looking for. See: https://www.haskell.org/ghc/docs/7.6.2/html/users_guide/ghci-commands.html as a reference.

Search for "macros" (or :def, which is the command to define macros). You can put these in the ghci.conf file.

For example (from the same URL indicated above):

Prelude> let mycd d = Directory.setCurrentDirectory d >> return "" Prelude> :def mycd mycd Prelude> :mycd ..

I hope this helps.

Answer 3

Possible not exactly what you need, but in case the quick-jumping function suffices try this as a first fix (invoked by :sbh ):

:def sbh (\arg -> return ("System.Directory.setCurrentDirectory \"Desktop/Sandbox/Haskell\""))

Your later solution might make use of the arg reference like in:

:def sbh (\arg -> return ("System.Directory.setCurrentDirectory " ++ "\"" ++ args ++ "\""))

Invoke the latter which by :sbh Desktop/Sandbox/Haskell then.