c,haskell , importing inline-c modules in ghci


importing inline-c modules in ghci

Question:

Tag: c,haskell

I would like to import some inline-c generated functions in a ghci session. All source and object files are in a src/ subfolder but I get import error:

src/Main.hs:3:8:
    Could not find module ‘Test1’

I include all files for reference. Thanks in advance

Main.hs

module Main where

import Test1

main = 
  test1

and the functionality to be imported

{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE TemplateHaskell #-}
module Test1 where

import qualified Language.C.Inline as C
import Foreign.C.Types

C.include "<stdio.h>"
C.include "<math.h>"

test1 = do
  s <- readAndSum n
  [C.exp| void{ printf( "Sum: %.2d\n", $(int s)) } |]
  putStrLn $ "Sum: " ++ show s

readAndSum n = 
  [C.block| int {
      int i, sum = 0, tmp;
      for (i = 0; i < $(int n); i++) {
        scanf("%d ", &tmp);
        sum += tmp;
      }
      return sum;
    } |]

makefile:

main:
    ghc -c src/Test1.hs 
    cc -c src/Test1.c -o src/Test1_c.o
    ghci src/Main.hs src/Test1_c.o -isrc/ 
    # ghci src/Main.hs -Lsrc/ 

UPDATE: I've fixed the makefile, the above now compiles. However the next big question is how to isolate effects within each call, i.e. resetting the values in a consistent manner.


Answer:

A minimal change to the ghci invocation did the job:

ghci src/Main.hs src/Test1_c.o -isrc/ 

which means that we add an include path with the -i flag to fix the Could not find module error, and explicitly link the object file generated from the inline-c snippets.


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