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acowley / roshask

Haskell client library for the ROS robotics framework.
BSD 3-Clause "New" or "Revised" License
107 stars 18 forks source link

Compatibility with Haskell Stack/Stackage #40

Open tjtolon opened 8 years ago

tjtolon commented 8 years ago

I made a new ros package with roshask create test std_msgs where roshask was installed via stack. However, executing roshask dep on the created package returns with

roshask: ghc-pkg: createProcess: runInteractiveProcess: exec: does not exist (No such file or directory)

I looked a bit into the code and noticed that roshask checks if the dependent have been build using ghc-pkg, or if something is cabal sandboxed, hc-pkg. Now, if I'm not completely wrong, there is no such thing as ghc-pkg for stack as it utilizes its own package database.

Is it true that for now the best option would be to install ghc and cabal on the system directly?

acowley commented 8 years ago

If you're up for it, the easiest thing may be to hack roshask to call stack exec hc-pkg. I'm not 100% certain on that stack exec syntax, but that's the way to use stack's tools. If the quick fix works, we can slot it into the logic that decides whether to use ghc-pkg or hc-pkg.

tjtolon commented 8 years ago

Now I tried it for a few minutes and it seems that just having cabal installed in stack's global project is not enough. At least cabal sandbox hc-pkg list ROS-std-msgs-0.3 returns with

cabal: The program 'ghc' version >=6.4 is required but it could not be found.

For me this quickly goes out of my expertise. For what I looked I'm not sure how to make a check wether a package is installed for the proper snapshot. Another ought to be added is the way how the generated cabal package is installed to the stack. I think stack.yaml should be made as well, but that could be easier with stack solver --modify-stack-yaml or stack init --solver

For my own purposes, I will be installing roshask/cabal/ghc directly, without stack, for now.

acowley commented 8 years ago

Proper stack support is a good idea, and given the traction stack has, is rapidly becoming a necessity. Thanks for bringing this up. I'll have to set up an environment for testing this.

acowley commented 8 years ago

I've started by adding a stack.yaml so roshask itself builds with stack. It also looks like stack exec ghc-pkg can get us installed package information. The last step @tjtolon mentioned of producing a stack.yaml for each package is still to-be-determined.