生產從單個項目的多個可執行文件

Question

用下面的項目結構：

src/FirstExecutable.hs 
src/SecondExecutable.hs 
my-amazing-project.cabal 

和下面的小集團設置：

name:    my-amazing-project 
version:   0.1.0.0 
build-type:   Simple 
cabal-version:  >=1.8 

executable first-executable 
    hs-source-dirs: src 
    main-is:   FirstExecutable.hs 
    ghc-options:  -O2 -threaded -with-rtsopts=-N 
    build-depends: base == 4.5.* 

executable second-executable 
    hs-source-dirs: src 
    main-is:   SecondExecutable.hs 
    ghc-options:  -O2 -threaded -with-rtsopts=-N 
    build-depends: base == 4.5.* 

運行cabal install失敗，並輸出如下：

Installing executable(s) in 
/Users/mojojojo/Library/Haskell/ghc-7.4.2/lib/my-amazing-project-0.1.0.0/bin 
cabal: dist/build/second-executable/second-executable: does not exist 
Failed to install my-amazing-project-0.1.0.0 
cabal: Error: some packages failed to install: 
my-amazing-project-0.1.0.0 failed during the final install step. The exception 
was: 
ExitFailure 1 

我做錯了什麼，或者這是一個Cabal錯誤？是

---

所述可執行模塊的內容如下：

module FirstExecutable where 

main = putStrLn "Running FirstExecutable" 

和

module SecondExecutable where 

main = putStrLn "Running SecondExecutable" 

Answer 1

小集團預計可執行的模塊是Main。您應該跳過模塊行或使用module Main where。

好的，這裏是可能的原因。當您實際編譯程序時，如果模塊不是Main，則不會生成haskell程序的可執行文件。運行可執行文件時使用Main模塊的main功能。 ghc可能的解決方法是-main-is標誌。所以你可以像

name:    my-amazing-project 
version:   0.1.0.0 
build-type:   Simple 
cabal-version:  >=1.8 

executable first-executable 
    hs-source-dirs: src 
    main-is:   FirstExecutable.hs 
    ghc-options:  -O2 -threaded -with-rtsopts=-N -main-is FirstExecutable 
    build-depends: base == 4.5.* 

executable second-executable 
    hs-source-dirs: src 
    main-is:   SecondExecutable.hs 
    ghc-options:  -O2 -threaded -with-rtsopts=-N -main-is SecondExecutable 
    build-depends: base == 4.5.*