I see your point, i.e., compiled, multi-file projects are not really meant for the REPL-dominant world of org-mode babel. Babel's sweet-spot would be the interpreted world, the very best probably a Lisp language. Still, the ability to add code to a running REPL should be possible. As I mentioned, SML is a sibling of Haskell and its babel implementation worked fine for me as I worked through an SML course. So yes, this appears to be a Haskell REPL issue. I'm just a beginner with Haskell, and all my intro texts start you out using the ghci REPL interactively. But then they switch you over to a text file compiled in the REPL with :l myfile.hs . . . no explanation as to why you can't just continue with the REPL putting the program in line-by-line. The fact that I can use the :set +m to include multiple lines of code, but cannot do a type definition is rather bizarre, though. This is a decision Haskell made with their REPL and babel really can't do much about it, I suppose. The Haskell .lhs literate option is interesting. Yes, I'd like to see your tangle option, please.
On Thu, Dec 10, 2020 at 4:28 AM Immanuel Litzroth < immanuel.litzr...@gmail.com> wrote: > I don't think org-babel is a good fit for compiled languages. If the > idea is to just take 1 snippet, > and "execute" that it means that to have a consistent whole you'd need > to put all the modules of > your program into that snippet (already impossible in Haskell, you can > have only 1 module per file), > compile that, run the resulting binary. Or org mode would have to have > some idea of what needs to > be retangled & rebuilt. > I think that using org-babel for compiled, multifile languages will > only work in very simple cases -- and > even then.. -- but will lead to problems very soon. > Immanuel > > On Thu, Dec 10, 2020 at 4:21 AM Lawrence Bottorff <borg...@gmail.com> > wrote: > > > > I'm looking into Haskell (latest ghci) again on org-mode. This > > > > #+begin_src haskell :results verbatim :exports both > > :set +m > > doubleSmallNumber x = if x > 100 > > then x > > else x*2 > > #+end_src > > > > works, but still the :set +m is necessary for it to see the whole. But > this > > > > #+begin_src haskell :results verbatim :exports both > > :set +m > > factorial :: Int -> Int > > factorial 0 = 1 > > factorial n = n * factorial (n - 1) > > #+end_src > > > > results in this on the REPL side: > > > > Prelude> :set +m > > factorial :: Int -> Int > > factorial 0 = 1 > > factorial n = n * factorial (n - 1) > > "org-babel-haskell-eoe" > > Prelude> > > <interactive>:26:1-23: error: > > • No instance for (Show (Int -> Int)) arising from a use of ‘print’ > > (maybe you haven't applied a function to enough arguments?) > > • In a stmt of an interactive GHCi command: print it > > Prelude> Prelude> Prelude> "org-babel-haskell-eoe" > > > > which is the same behavior if I try to feed the program into the REPL > one line at a time, i.e., > > > > Prelude> factorial :: Int -> Int > > > > <interactive>:40:1-23: error: > > • No instance for (Show (Int -> Int)) arising from a use of ‘print’ > > (maybe you haven't applied a function to enough arguments?) > > • In a stmt of an interactive GHCi command: print it > > > > So the :set +m trick (take multiple lines) doesn't help here. Obviously, > Haskell is not ready to be used with Babel. Can it be fixed? BTW, this does > work with the regular ghci REPL and haskell-mode. If it helps, Standard ML, > which has very similar syntax (it was Haskell's parent), works fine. > > > > LB > > > > -- > -- Researching the dual problem of finding the function that has a > given point as fixpoint. >
