Compiling Haskell to JavaScript using GHCJS and Haskell Stack

Question

How can Haskell be compiled to Javascript using GHCJS and Haskell Stack?

I have the current version of Haksell Stack 1.5.1.

I can initialize a GHCJS project with this command: stack new ghcjsSetup ghcjs

Once in the project directory I try following the Stack documentation for GHCJS.

I create a stack.yaml file and edit it to match the example from the documentation so that is looks like this.

resolver: lts-7.19
compiler: ghcjs-0.2.1.9007019_ghc-8.0.1
compiler-check: match-exact

setup-info:
  ghcjs:
    source:
      ghcjs-0.2.1.9007019_ghc-8.0.1:
        url: http://ghcjs.tolysz.org/ghc-8.0-2017-02-05-lts-7.19-9007019.tar.gz
        sha1: d2cfc25f9cda32a25a87d9af68891b2186ee52f9

Following the documentation further I try to install and boot GHCJS with this command:

stack setup

This command produces an output which ends with an error.

Preparing to install GHCJS to an isolated location.
This will not interfere with any system-level installation.
Preparing to download ghcjs-0.2.1.9007019_ghc-8.0.1 ...
Already downloaded.
Unpacking GHCJS into /home/u/.stack/programs/x86_64-linux/ghcjs-0.2.1.9007019_ghc-8.0.1/src/ ...
Setting up GHCJS build environment
Installing GHCJS (this will take a long time) ...
ghcjs-0.2.1.9007019: configure (lib + exe)
Package ghcjs uses a custom Cabal build, but does not use a custom-setup stanza
Using the explicit setup deps approach based on configuration
Strongly recommend fixing the package's cabal file
[1 of 2] Compiling Main             ( /home/u/.stack/programs/x86_64-linux/ghcjs-0.2.1.9007019_ghc-8.0.1/src/Setup.hs, /home/u/.stack/programs/x86_64-linux/ghcjs-0.2.1.9007019_ghc-8.0.1/src/.stack-work/dist/x86_64-linux/Cabal-1.24.0.0/setup/Main.o )
[2 of 2] Compiling StackSetupShim   ( /home/u/.stack/setup-exe-src/setup-shim-mPHDZzAJ.hs, /home/u/.stack/programs/x86_64-linux/ghcjs-0.2.1.9007019_ghc-8.0.1/src/.stack-work/dist/x86_64-linux/Cabal-1.24.0.0/setup/StackSetupShim.o )
Linking /home/u/.stack/programs/x86_64-linux/ghcjs-0.2.1.9007019_ghc-8.0.1/src/.stack-work/dist/x86_64-linux/Cabal-1.24.0.0/setup/setup ...
Configuring ghcjs-0.2.1.9007019...
ghcjs-0.2.1.9007019: build (lib + exe)
Preprocessing library ghcjs-0.2.1.9007019...

/home/u/.stack/programs/x86_64-linux/ghcjs-0.2.1.9007019_ghc-8.0.1/src/src/Compiler/JMacro/Base.hs:1:55: warning:
    -XOverlappingInstances is deprecated: instead use per-instance pragmas OVERLAPPING/OVERLAPPABLE/OVERLAPS

/home/u/.stack/programs/x86_64-linux/ghcjs-0.2.1.9007019_ghc-8.0.1/src/src/Compiler/JMacro/QQ.hs:1:55: warning:
    -XOverlappingInstances is deprecated: instead use per-instance pragmas OVERLAPPING/OVERLAPPABLE/OVERLAPS
[ 1 of 50] Compiling GHCJS.Prim.TH.Serialized ( lib/ghcjs-prim/GHCJS/Prim/TH/Serialized.hs, .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/GHCJS/Prim/TH/Serialized.o )

Because it is too long to post here I have excluded the middle of the output. Which includes lots of warning messages.

[49 of 50] Compiling Compiler.Program ( src/Compiler/Program.hs, .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/Compiler/Program.o )
[50 of 50] Compiling GHCJS            ( src/GHCJS.hs, .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/GHCJS.o )
Preprocessing executable 'ghcjs' for ghcjs-0.2.1.9007019...
[1 of 1] Compiling Main             ( src-bin/Main.hs, .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/ghcjs/ghcjs-tmp/Main.o )
Linking .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/ghcjs/ghcjs ...
Preprocessing executable 'ghcjs-boot' for ghcjs-0.2.1.9007019...
[1 of 1] Compiling Main             ( src-bin/Boot.hs, .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/ghcjs-boot/ghcjs-boot-tmp/Main.o )

/home/u/.stack/programs/x86_64-linux/ghcjs-0.2.1.9007019_ghc-8.0.1/src/src-bin/Boot.hs:690:1: warning: [-Wtabs]
    Tab character found here, and in three further locations.
    Please use spaces instead.
Linking .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/ghcjs-boot/ghcjs-boot ...
Preprocessing executable 'ghcjs-pkg' for ghcjs-0.2.1.9007019...
[1 of 1] Compiling Main             ( src-bin/Pkg.hs, .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/ghcjs-pkg/ghcjs-pkg-tmp/Main.o )
Linking .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/ghcjs-pkg/ghcjs-pkg ...
/usr/bin/ld: cannot find -ltinfo
collect2: error: ld returned 1 exit status
`gcc' failed in phase `Linker'. (Exit code: 1)

--  While building package ghcjs-0.2.1.9007019 using:
      /home/u/.stack/programs/x86_64-linux/ghcjs-0.2.1.9007019_ghc-8.0.1/src/.stack-work/dist/x86_64-linux/Cabal-1.24.0.0/setup/setup --builddir=.stack-work/dist/x86_64-linux/Cabal-1.24.0.0 build lib:ghcjs exe:ghcjs exe:ghcjs-boot exe:ghcjs-pkg exe:ghcjs-run exe:haddock-ghcjs exe:hsc2hs-ghcjs --ghc-options " -ddump-hi -ddump-to-file"
    Process exited with code: ExitFailure 1

Answer 1

"Linking .stack-work/dist/x86_64-linux/Cabal-1.24.0.0/build/ghcjs-pkg/ghcjs-pkg ... /usr/bin/ld: cannot find -ltinfo"

You are missing the libtinfo library which is part of ncurses. Depending on your environment try something like:

sudo apt-get install libtinfo-dev

---

As an aside, getting all the pieces that ghcjs needs to build successfully is tricky and not well documented as of September 2018. One might hope that as the project matures it will get easier to install, and that a binary package will be produced. Know that you are not the only person who has these issues. It takes some patience and trial-and-error to get ghcjs working right now.

Others have had success using nix, I did not.