使用GHC API时查找cabal包

Question

我正在尝试使用GHC API为我制作一个类似于我的文件的程序.我已经进行了类型检查以便为本地文件工作,但我有一个特定的cabal包,我需要也可以使用(这个可执行文件将属于同一个包).如何添加此导入依赖项？

我也尝试用ghc命令行编译来解决这个问题,ghc -package PKG-VER --make Test.hs -v但它似乎只是在本地目录中查找导入.

我当前的代码如下所示:

import           Control.Exception
import           Control.Monad
import           Control.Monad.State
import           DynFlags
import           Exception
import           GHC
import           GHC.Paths           (libdir)
typecheck :: MonadIO m => [FilePath] -> FilePath -> m ()
typecheck otherincludes fp =
  liftIO . defaultErrorHandler defaultLogAction . runGhc (Just libdir) $ do
    dynflags <- getSessionDynFlags
    void $ setSessionDynFlags dynflags { includePaths = otherIncludes ++ includePaths dynflags }
    target <- guessTarget fp Nothing
    setTargets [target]
    void $ load LoadAllTargets
    deps <- depanal [] False
    forM_ deps $ \ms -> parseModule ms >>= typecheckModule

Answer 1

我设法将您的代码读取并进行类型检查,如下所示:

package Test where
import           Control.Exception
import           Control.Monad
import           Control.Monad.State
import           DynFlags
import           Exception
import           GHC
import           GHC.Paths           (libdir)
typecheck :: MonadIO m => [FilePath] -> FilePath -> m ()
typecheck otherincludes fp =
  liftIO . defaultErrorHandler defaultLogAction . runGhc (Just libdir) $ do
    dynflags <- getSessionDynFlags
    void $ setSessionDynFlags dynflags {
        includePaths = otherincludes ++ includePaths dynflags,
        packageFlags = [ExposePackage "ghc"]} }
    target <- guessTarget fp Nothing
    setTargets [target]
    void $ load LoadAllTargets
    deps <- depanal [] False
    forM_ deps $ \ms -> parseModule ms >>= typecheckModule

这是它在ghci中的运行方式:

$ ghci Test.hs -package ghc
GHCi, version 7.4.1: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package array-0.4.0.0 ... linking ... done.
Loading package deepseq-1.3.0.0 ... linking ... done.
Loading package containers-0.4.2.1 ... linking ... done.
Loading package filepath-1.3.0.0 ... linking ... done.
Loading package old-locale-1.0.0.4 ... linking ... done.
Loading package old-time-1.1.0.0 ... linking ... done.
Loading package bytestring-0.9.2.1 ... linking ... done.
Loading package unix-2.5.1.0 ... linking ... done.
Loading package directory-1.1.0.2 ... linking ... done.
Loading package pretty-1.1.1.0 ... linking ... done.
Loading package process-1.1.0.1 ... linking ... done.
Loading package Cabal-1.14.0 ... linking ... done.
Loading package binary-0.5.1.0 ... linking ... done.
Loading package bin-package-db-0.0.0.0 ... linking ... done.
Loading package hoopl-3.8.7.3 ... linking ... done.
Loading package hpc-0.5.1.1 ... linking ... done.
Loading package template-haskell ... linking ... done.
Loading package ghc-7.4.1 ... linking ... done.
Ok, modules loaded: Test.
Prelude Test> typecheck [] "Test.hs"
Loading package transformers-0.3.0.0 ... linking ... done.
Loading package mtl-2.1.1 ... linking ... done.
Prelude Test> 

所以诀窍似乎是将dynflags参数中公开的包传递给setSessionDynFlags.有关一些文档,请参见DynFlags模块.