生产从单个项目的多个可执行文件

Question

用下面的项目结构：

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

和下面的小集团设置：

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.* 

运行cabal install失败，并输出如下：

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 

我做错了什么，或者这是一个Cabal错误？是

---

所述可执行模块的内容如下：

module FirstExecutable where 

main = putStrLn "Running FirstExecutable" 

和

module SecondExecutable where 

main = putStrLn "Running SecondExecutable" 

Answer 1

小集团预计可执行的模块是Main。您应该跳过模块行或使用module Main where。

好的，这里是可能的原因。当您实际编译程序时，如果模块不是Main，则不会生成haskell程序的可执行文件。运行可执行文件时使用Main模块的main功能。 ghc可能的解决方法是-main-is标志。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.*