cabal

问题 I am a beginner with Haskell and for an assignment I needed to install System.Random. So I installed the package using Cabal through command line (originally with cabal install random and then with cabal install --lib random ), however, when I run GHCI it doesn't recognize that the package is installed. When I run it I get this error: Could not find module `System.Random' Use -v to see a list of the files searched for. | 3 | import System.Random | ^^^^^^^^^^^^^^^^^^^^ Failed, no modules

问题 I'm trying install tidal in command line this way: cabal install tidal but it ends with this message: Warning: You asked to install executables, but there are no executables in target: tidal. Perhaps you want to use --lib to install libraries instead. Return of: cabal install tidal --lib is: Resolving dependencies... Up to date If I check ghk-pkg list, there is no package tidal ... Have somebody similar problem or what I'm doing wrong? My environment is: Windows 10 Education Haskell 8.4.3

问题 I would like to install 'readline' using Cabal on Windows. When running the command it is saying that readline isn't found. Cabal is up to date. Command cabal install readline Output Resolving dependencies... Notice: installing into a sandbox located at C:\Users\Michael\Desktop\haskell-project\.cabal-sandbox Configuring readline-1.0.3.0... Failed to install readline-1.0.3.0 Build log ( C:\Users\Michael\Desktop\haskell-project\.cabal-sandbox\logs\readline-1.0.3.0.log ): Configuring readline-1

问题 I would like to install 'readline' using Cabal on Windows. When running the command it is saying that readline isn't found. Cabal is up to date. Command cabal install readline Output Resolving dependencies... Notice: installing into a sandbox located at C:\Users\Michael\Desktop\haskell-project\.cabal-sandbox Configuring readline-1.0.3.0... Failed to install readline-1.0.3.0 Build log ( C:\Users\Michael\Desktop\haskell-project\.cabal-sandbox\logs\readline-1.0.3.0.log ): Configuring readline-1

问题 I would like to install 'readline' using Cabal on Windows. When running the command it is saying that readline isn't found. Cabal is up to date. Command cabal install readline Output Resolving dependencies... Notice: installing into a sandbox located at C:\Users\Michael\Desktop\haskell-project\.cabal-sandbox Configuring readline-1.0.3.0... Failed to install readline-1.0.3.0 Build log ( C:\Users\Michael\Desktop\haskell-project\.cabal-sandbox\logs\readline-1.0.3.0.log ): Configuring readline-1

问题 I need glib for threadscope to work. But I am not able to install it using cabal. I tried cabal install glib but getting the following error. I even tried downloading the library and installing it locally but get the same error. I am using Cygwin on Windows. I ran Cygwin setup to make sure I have the missing libraries. I was able to find glib, gobject but not gthread. Gtk2HsSetup.hs:25:2: warning: #warning Setup.hs is guessing the version of Cabal. If compilation of Setup.hs fails use -DCABAL

问题 I need glib for threadscope to work. But I am not able to install it using cabal. I tried cabal install glib but getting the following error. I even tried downloading the library and installing it locally but get the same error. I am using Cygwin on Windows. I ran Cygwin setup to make sure I have the missing libraries. I was able to find glib, gobject but not gthread. Gtk2HsSetup.hs:25:2: warning: #warning Setup.hs is guessing the version of Cabal. If compilation of Setup.hs fails use -DCABAL

问题 I am trying to tell whether two files are likely the same, and found I could make a MD5 hash in Haskell from this StackOverflow thread: Compute MD5 digest of file in Haskell When I try to install pureMD5, I get an error: $ cabal install --lib pureMD5 Resolving dependencies... cabal: Could not resolve dependencies: [__0] trying: base-4.12.0.0/installed-4.1... (user goal) [__1] trying: ghc-8.6.5/installed-8.6... (user goal) [__2] next goal: process (user goal) [__2] rejecting: process-1.6.6.0

问题 I wanted to use the Control.Monad.Except module, but it turned out I had an outdated mtl package (It caused an import error - I had an obsolete module Control.Monad.Error ). So I did sudo cabal install mtl And it installed the 2.2.2 version. However, now I had two versions installed, 2.1.2 and 2.2.2 which still caused an import error. I followed instructions here and did sudo ghc-pkg unregister --force mtl-2.1.2 to remove the old version. But now I get an error: Could not find module `Control

问题 I am currently trying to get started with Haskell because I want to use parts of the code base of Pandoc for a different project. Since I am new to Haskell I need proper IDE features like code completion and jump to definition AND type information and documentation on hover . I chose VSCode with the Haskell extension for the job. Now comes my problem: Pandoc depends on pandoc-types which is an integral part of the code, which I need to understand and modify. But using the ghc-option "