为什么cabal安装会重新编译构建的内容？

Question

为什么当我这样做cabal build,然后cabal install,阴谋重新编译的事情两次.(我正在使用沙箱).

更新

为了澄清,我问在做什么之后cabal build(我理解编译我的文件的2个版本),为什么要再做cabal install一次编译.这不是build建立的目的吗？

UPDATE2

好吧,似乎在两个不同的目录来编译dist和dist/sandbox-... 就是在两者之间有什么区别？

> cabal build
Building cache-0.1.0.0...
Preprocessing executable 'cache' for cache-0.1.0.0...
[1 of 1] Compiling Main             ( main.hs, dist/build/cache/cache-tmp/Main.o )
Linking dist/build/cache/cache ...

> cabal install
Warning: The package list for 'hackage.haskell.org' is 60 days old.
Run 'cabal update' to get the latest list of available packages.
Resolving dependencies...
Configuring cache-0.1.0.0...
Warning: The 'license-file' field refers to the file 'LICENSE' which does not exist.
Building cache-0.1.0.0...  
Preprocessing executable 'cache' for cache-0.1.0.0...
[1 of 1] Compiling Main             ( main.hs, dist/dist-sandbox-db136cca/build/cache/cache-tmp/Main.o )
Linking dist/dist-sandbox-db136cca/build/cache/cache ...

Answer 1

在 a 期间cabal build，它会创建两个版本的已编译代码 - 一种带有分析，另一种不带有分析。

命令行参数的差异非常微小，很容易被忽略。在以下输出中，第一个是用 编译的-O -j2，第二个是用 编译的-O -prof -j2。此外，输出文件具有不同的后缀 -.o与.p_o：

Preprocessing library split-0.2.2...
Building library...
creating dist/build
/usr/bin/ghc --make -fbuilding-cabal-package -O -j2 -static -dynamic-too -dynosuf dyn_o -dynhisuf dyn_hi -outputdir dist/build -odir dist/build -hidir dist/build -stubdir dist/build -i -idist/build -isrc -idist/build/autogen -Idist/build/autogen -Idist/build -optP-include -optPdist/build/autogen/cabal_macros.h -package-name split-0.2.2 -hide-all-packages -no-user-package-db -package-db /Users/erantapaa/try/split-0.2.2/.cabal-sandbox/x86_64-osx-ghc-7.8.3-packages.conf.d -package-db dist/package.conf.inplace -package-id base-4.7.0.1-df210ede1eb79477fef5662549c32927 -XHaskell2010 Data.List.Split Data.List.Split.Internals -Wall
[1 of 2] Compiling Data.List.Split.Internals ( src/Data/List/Split/Internals.hs, dist/build/Data/List/Split/Internals.o )
[2 of 2] Compiling Data.List.Split  ( src/Data/List/Split.hs, dist/build/Data/List/Split.o )
/usr/bin/ghc --make -fbuilding-cabal-package -O -prof -j2 -osuf p_o -hisuf p_hi -outputdir dist/build -odir dist/build -hidir dist/build -stubdir dist/build -i -idist/build -isrc -idist/build/autogen -Idist/build/autogen -Idist/build -optP-include -optPdist/build/autogen/cabal_macros.h -package-name split-0.2.2 -hide-all-packages -no-user-package-db -package-db /Users/erantapaa/try/split-0.2.2/.cabal-sandbox/x86_64-osx-ghc-7.8.3-packages.conf.d -package-db dist/package.conf.inplace -package-id base-4.7.0.1-df210ede1eb79477fef5662549c32927 -XHaskell2010 Data.List.Split Data.List.Split.Internals -Wall
[1 of 2] Compiling Data.List.Split.Internals ( src/Data/List/Split/Internals.hs, dist/build/Data/List/Split/Internals.p_o )
[2 of 2] Compiling Data.List.Split  ( src/Data/List/Split.hs, dist/build/Data/List/Split.p_o )
Linking...