I'd like to use hsc2hs via Stack and HPack. The problem is, since HPack doesn't allow me to list the .hsc file as a source file, only .hs, changes to the .hsc file don't trigger a rebuild in stack build.
My package.yaml file is as follows:
name: bounce-bench
version: 0.1.0
category: acme
dependencies:
- base
source-dirs:
- src
executables:
sim-ffi:
source-dirs: sim
main: sim-ffi.hs
build-tools: hsc2hs
c-sources:
- csim/Bounce.h
- csim/Bounce.c
include-dirs: csim
With the above file, the initial stack build succeeds (incl. building sim-ffi.hs from sim-ffi.hsc), however, subsequent stack build invocations don't do anything if sim-ffi.hsc is changed.
If I try to change the main key's value from sim-ffi.hs to sim-ffi.hsc, I am explicitly told off:
Cabal-simple_mPHDZzAJ_2.4.0.1_ghc-8.6.5: The 'main-is' field must specify a
'.hs' or '.lhs' file (even if it is generated by a preprocessor), or it may
specify a C/C++/obj-C source file.
Related
I have projects compiling with cabal build (but using hpack for the convenience). For some reason, I would like to compile them with stack build. What goes into a minimal stack.yaml file?
The stack documentation gives details what goes into such a file, but does not show a minimal (or any, as much as I can see) example. I fear to use stack init on an existing project for unintended consequences.
What is a small example from which to go?
A minimal stack.yaml:
resolver: lts-19.16 # for ghc 9.0.2 newest lts
packages:
- .
A not-so minimal skeleton from which to expand:
resolver: lts-19.16 # for ghc 9.0.2 newest lts
packages:
- .
extra-deps: # include here other local packages
ghc-options:
"$everything": -haddock # to produce documentation with haddock
I am trying to add dependency of gtk2hs-buildtool to my Haskell project but following error while building stack.
In the dependencies for TicTacToe-0.1.0.0:
gtk2hs-buildtools needed, but the stack configuration has no specified version (latest matching
version is 0.13.5.4)
needed since TicTacToe is a build target.
TicTacToe.cabal file:
library
exposed-modules:
TicTacToeEngine
other-modules:
Paths_TicTacToe
hs-source-dirs:
src
build-depends:
base >=4.7 && <5,
gtk2hs-buildtools
default-language: Haskell2010
If you are using stack tool you shouldn't touch the <packagename>.cabal file. stack is in charge to generate it from package.yaml. Despite of the fact that is a common practise to modify the <packagename>.cabal, development workflow will be easier if you don't.
The files you are interested in (and the ones that stack tool uses) are the stack.yaml and package.yaml.
In stack.yaml you should see an entry called resolver: lts-XX.XX. That means that your dependencies version are managed such that they match those in the given lts (a.k.a. snapshot). You can go to https://www.stackage.org/, click on your lts version and search for the gtk2hs-buildtools package to get the right version for your project (example: lts-12.26 uses gtk2hs-buildtools-0.13.4.0). In your package.yaml, in the dependencies section write the entry entry - gtk2hs-buildtools
From lts-13.11 and above gtk2hs-buildtools is not available in stackage, so you need to add it as an extra-dep. in the stack.yaml, in the section extra-dep add the following entry gtk2hs-buildtools-0.13.4.0 (or the version number you'd like to use). Then add in the package.yaml and entry gtk2hs-buildtools. It is necessary to add the entry in both files. Refer to stack docs o understand why.
Just to ensure you can build your project, your files should something look like the following:
if using resolver above or equal to 13.11
stack.yaml
resolver: lts-13.11
extra-deps:
- gtk2hs-buildtools-0.13.4.0
package.yaml
dependencies:
- base
- gtk2hs-buildtools
if using resolver below 13.11
stack.yaml
resolver: lts-12.26
extra-deps:
package.yaml
dependencies:
- base
- gtk2hs-buildtools
I am attempting to build a project which uses Euterpea.
Running stack build I get the following error, suggesting that I need to add Euterpea to the build-depends section of my .cabal file.
$ sb
composition-0.1.0.0: build (lib + exe)
Preprocessing library composition-0.1.0.0...
[2 of 2] Compiling Lib ( src/Lib.hs, .stack-work/dist/x86_64-linux-nix/Cabal-1.24.2.0/build/Lib.o )
/home/matthew/backup/composition/composition/src/Lib.hs:5:1: error:
Failed to load interface for ‘Euterpea’
It is a member of the hidden package ‘Euterpea-2.0.4’.
Perhaps you need to add ‘Euterpea’ to the build-depends in your .cabal file.
Use -v to see a list of the files searched for.
-- While building package composition-0.1.0.0 using:
/home/matthew/.stack/setup-exe-cache/x86_64-linux-nix/Cabal-simple_mPHDZzAJ_1.24.2.0_ghc-8.0.2 --builddir=.stack-work/dist/x86_64-linux-nix/Cabal-1.24.2.0 build lib:composition exe:composition-exe --ghc-options " -ddump-hi -ddump-to-file"
Process exited with code: ExitFailure 1
I add Euterpea there, and the library section of my .cabal file then is the following.
library
hs-source-dirs:
src
build-depends: base >= 4.7 && < 5
, Euterpea
exposed-modules:
Lib
other-modules:
Paths_composition
default-language: Haskell2010
However, when I then run stack build again, it gives the same error -- and changes my .cabal file back to what it was originally, with the library section then looking like
library
hs-source-dirs:
src
build-depends:
base >= 4.7 && < 5
exposed-modules:
Lib
other-modules:
Paths_composition
default-language: Haskell2010
Why is stack build altering my cabal file? I have never seen that occurring before.
Side note:
Not sure if it is related, but the .cabal file's format appears to be different than it normally does. Here as with previous projects I auto-initialized by running stack new <project-name>. I don't know what I might have done different from previous projects to cause this unexpected behavior of stack build.
Make sure package.yaml exists in the root of your project directory.
package.yaml is a new file format to improve the syntax of cabal, converted by hpack.
Stack supports hpack as strongly as the stack build command automatically converts package.yaml into a cabal file with hpack command.
So, delete package.yaml or edit package.yaml to add Euterpea package.
Editing it would not be so difficult as its format is YAML.
I want to add to the YAMAMOTO Yuji's answer. The solution is absolutely right. But I just wanted to add few things, it is not hard to edit the package.yaml.
Step 1 : The trickiest part is finding the correct package name.
Use Hoogle or Stackage to find the package where the module
resides. Read more about how to find package name in this post.
Step 2 : Now you have to open the package.yaml file and add the package name. In your case add 'Euterpea' package in the list of dependencies.
dependencies:
...
- your-package-name
Please note that Euterpea package has to be added in a different way. Please read this
post for better understanding.
Step 3 : Open project-name.cabal in project root and add required package name under build-depends:
library
hs-source-dirs:
src
build-depends:
base >= 4.7 && < 5
, your-package-name
exposed-modules:
Lib
Step 4 :Issue stack build to download and build dependencies
(or stack ghci if you plan to use it in the REPL)
Hope this works! Happy coding! :)
I am attempting to build a project which uses Euterpea.
Running stack build I get the following error, suggesting that I need to add Euterpea to the build-depends section of my .cabal file.
$ sb
composition-0.1.0.0: build (lib + exe)
Preprocessing library composition-0.1.0.0...
[2 of 2] Compiling Lib ( src/Lib.hs, .stack-work/dist/x86_64-linux-nix/Cabal-1.24.2.0/build/Lib.o )
/home/matthew/backup/composition/composition/src/Lib.hs:5:1: error:
Failed to load interface for ‘Euterpea’
It is a member of the hidden package ‘Euterpea-2.0.4’.
Perhaps you need to add ‘Euterpea’ to the build-depends in your .cabal file.
Use -v to see a list of the files searched for.
-- While building package composition-0.1.0.0 using:
/home/matthew/.stack/setup-exe-cache/x86_64-linux-nix/Cabal-simple_mPHDZzAJ_1.24.2.0_ghc-8.0.2 --builddir=.stack-work/dist/x86_64-linux-nix/Cabal-1.24.2.0 build lib:composition exe:composition-exe --ghc-options " -ddump-hi -ddump-to-file"
Process exited with code: ExitFailure 1
I add Euterpea there, and the library section of my .cabal file then is the following.
library
hs-source-dirs:
src
build-depends: base >= 4.7 && < 5
, Euterpea
exposed-modules:
Lib
other-modules:
Paths_composition
default-language: Haskell2010
However, when I then run stack build again, it gives the same error -- and changes my .cabal file back to what it was originally, with the library section then looking like
library
hs-source-dirs:
src
build-depends:
base >= 4.7 && < 5
exposed-modules:
Lib
other-modules:
Paths_composition
default-language: Haskell2010
Why is stack build altering my cabal file? I have never seen that occurring before.
Side note:
Not sure if it is related, but the .cabal file's format appears to be different than it normally does. Here as with previous projects I auto-initialized by running stack new <project-name>. I don't know what I might have done different from previous projects to cause this unexpected behavior of stack build.
Make sure package.yaml exists in the root of your project directory.
package.yaml is a new file format to improve the syntax of cabal, converted by hpack.
Stack supports hpack as strongly as the stack build command automatically converts package.yaml into a cabal file with hpack command.
So, delete package.yaml or edit package.yaml to add Euterpea package.
Editing it would not be so difficult as its format is YAML.
I want to add to the YAMAMOTO Yuji's answer. The solution is absolutely right. But I just wanted to add few things, it is not hard to edit the package.yaml.
Step 1 : The trickiest part is finding the correct package name.
Use Hoogle or Stackage to find the package where the module
resides. Read more about how to find package name in this post.
Step 2 : Now you have to open the package.yaml file and add the package name. In your case add 'Euterpea' package in the list of dependencies.
dependencies:
...
- your-package-name
Please note that Euterpea package has to be added in a different way. Please read this
post for better understanding.
Step 3 : Open project-name.cabal in project root and add required package name under build-depends:
library
hs-source-dirs:
src
build-depends:
base >= 4.7 && < 5
, your-package-name
exposed-modules:
Lib
Step 4 :Issue stack build to download and build dependencies
(or stack ghci if you plan to use it in the REPL)
Hope this works! Happy coding! :)
I want to use reactive-banana in my new Haskell project. I never used cabal-install or stack before. I created a directory and initialized project files in it using stack new. I see now 2 files in the directory: new-template.cabal and stack.yaml.
How do I set dependencies and make sure they are downloaded and compiled?
At first I tried to add - reactive-banana-0.8.0.2 in stack.yaml under extra-deps:, but both stack build and stack solver didn't download it. Then I augmented a part called library in new-template.cabal to this:
library
hs-source-dirs: src
exposed-modules: Lib
build-depends: base >= 4.7 && < 5
, reactive-banana >= 0.8
default-language: Haskell2010
Every time I tried to run stack build, it crashed with an error and suggestion to add some package to stack.yaml under extra-deps:, and this happened three times until finally all packages installed, and I could import them in stack ghci REPL.
So my question is, what is the idiomatic way to use stack? Which of these 2 files should I use to specify dependencies and other project metadata? What is the sample workflow of an average Haskell developer with stack?
When using stack I generally don't put any versions bounds in my .cabal file. I let the resolver and extra-deps setting in the stack.yaml file determine which versions of packages to select.
Here is a stack.yaml file which brings in reactive-banana-0.8.1.2:
flags: {}
packages:
- '.'
extra-deps:
- reactive-banana-0.8.1.2
- psqueues-0.2.0.2
resolver: lts-2.17
In my .cabal file I just have:
build-depends: base >= 4.7 && < 5, reactive-banana
The reactive-banana version is pinned by the stack.yaml file.
If you want to use GHC 7.10 change the resolver to something like nightly-2015-06-17.
I determine the extra-deps iteratively, by just running stack build and adding whatever dependencies are missing to the stack.yaml file until all dependencies are satisfied.
You will only need to do this with packages which are not in Stackage - like reactive-banana. A great many of commonly used packages are in Stackage and their versions will be determined by the resolver setting.
In the default configuration, stack works with two package databases: a centralised per-user one and a project-specific one. The centralised database only pulls packages from Stackage, a subset of Hackage with known-to-be-compatible packages, while you can put whatever you want on the project-specific database. All packages you use must be in the cabal file, but those not on Stackage (that is, the ones that will go to the project-specific database) must also be listed in the extra-deps section of stack.yaml. reactive-banana is not on Stackage, so you need to add it to stack.yaml, like this:
# etc.
extra-deps:
- reactive-banana-0.8.1.2
# etc.
stack solver can fill in the extra dependencies in stack.yaml for you.