I start a new project library with cabal. here is the .cabal file
cabal-version: 2.4
library
exposed-modules: MyLib
build-depends: base ^>=4.14.3.0
, vector
hs-source-dirs: src
default-language: Haskell2010
I then use some Data.Vector functions inside my code. Here is the MyLib source
module MyLib (someFunc) where
import qualified Data.Vector as V
func :: [a] -> V.Vector a
func a = V.fromList a
But Data.Vector module remains underlined in red and this error is shown inside Vcode:
Could not load module ‘Data.Vector’
It is a member of the hidden package ‘vector-0.13.0.0’.
the func function works when in cabal repl
when I try cabal install vector this error appears:
Wrote tarball sdist to
/home/. .. .tar.gz
Resolving dependencies...
cabal: Cannot build the executables in the package vector because it does not
contain any executables. Check the .cabal file for the package and make sure
that it properly declares the components that you expect.
I don't understand what I am doing wrong? I told I understood the workings of cabal: I import a module as a dependency in .cabal, and I should be able to use it? why VSC does tell me he can't find it?
Related
I'm trying to add a library (a cmake project) to my Yocto project/image.
The package essentially consists of one static library (named hello.a) with some header files in C.
I wrote a recipe and could configure, compile, package it.
The packaging results are four files {hello-dbg, hello-dev, hello-src, hello-staticdev}.deb
So there is no hello.deb.
And that seems to be a problem preventing me to create image.
The following packages have unmet dependencies:
packagegroup-utils-extra : Depends: hello but it is not installable
E: Unable to correct problems, you have held broken packages.
When I try to add that by defining:
FILES_${PN} += "/usr/lib/hello.a"
bitbake does not allow adding static libraries to anything but staticdev -> so that does not work.
My question is then, as the title says, how to (force Yocto to) create ${PN}.deb file?
The empty packages (i.e. containing no files) are not created by default. If you want to override it, you can do it via the ALLOW_EMPTY variable for a package like this:
ALLOW_EMPTY:${PN} = "1"
You can also check the official documentation for ALLOW_EMPTY.
Just for clarification:
You can install the ${PN} package (it won't install any file on the target system).
As before, your static library will still be shipped in the ${PN}-staticdev package.
I am having trouble installing a module I created in Julia. I am running the Julia plugin under Visual Studio Code. If I run the file below with Ctrl+F5 I get a message
ERROR: LoadError: ArgumentError: Package Utils not found in current path:
- Run `import Pkg; Pkg.add("Utils")` to install the Utils package.
This is the file:
module demo
using Utils
greet() = print("Hello World!")
end # module
If I follow the advice on the error message I get another error message:
ERROR: LoadError: The following package names could not be resolved:
* Utils (not found in project, manifest or registry)
I also tried inserting this line:
import Pkg; Pkg.add(path="C:/Dropbox/Code/Julia/demo/src/Utils.jl")
and got this message (although the path definitely exists):
ERROR: LoadError: Path `C:/Dropbox/Code/Julia/demo/src/Utils.jl` does not exist.
The files demo.jl and Utils.jl are in C:\Dropbox\Code\Julia\demo\src\ and the demo project has been activated as can be seen in the REPL. The OS is Windows 10 Pro.
Any help will be greatly appreciated. Lots of time wasted trying to make this work.
Module and packages are not the same things. In short, packages are modules plus a set of metadata that make it easy for the package to be found and interact well with other packages. See here for a tutorial to write Julia packages:
https://syl1.gitbook.io/julia-language-a-concise-tutorial/language-core/11-developing-julia-packages
In your case, if you want to load a local module, just type include("fileWhereThereIsTheModule.jl") followed by a using Main.MyModule or using .MyModule. Note the dot... without it, Julia would indeed look for a package and to let it find your Demo or Util module you would have to either change an environmental variable or place your module file in certain predefined folders. Using include followed by the "absolute or relative position" of the module you don't have to do either.
I'm trying to build a Swift Package Manager system package (a module.modulemap)
making available two system C libraries where one includes the other.
That is, one (say libcurl) is a base module and the other C library is including
that (like so: #include "libcurl.h"). On the regular C side this works, because
the makefiles pass in proper -I flags and all is good (and I could presumably
do the same in SPM, but I'd like to avoid extra flags to SPM).
So what I came up with is this module map:
module CBase [system] {
header "/usr/include/curl.h"
link "curl"
export *
}
module CMyLib [system] {
use CBase
header "/usr/include/mylib.h"
link "mylib"
export *
}
I got importing CBase in a Swift package working fine.
But when I try to import CMyLib, the compiler complains:
error: 'curl.h' file not found
Which is kinda understandable because the compiler doesn't know where to look
(though I assumed that use CBase would help).
Is there a way to get this to work w/o having to add -Xcc -I flags to the
build process?
Update 1: To a degree this is covered in
Swift SR-145
and
SE-0063: SwiftPM System Module Search Paths.
The recommendation is to use the Package.swift pkgConfig setting. This seems to work OK for my specific setup. However, it is a chicken and egg if there is no .pc file. I tried embedding an own .pc file in the package, but the system package directory isn't added to the PKG_CONFIG_PATH (and hence won't be considered during the compilation of a dependent module). So the question stands: how to accomplish that in an environment where there libs are installed, but w/o a .pc file (just header and lib).
I was following a coq HelloWorld tutorial (code below), and couldn't get the program to compile. I followed the installation steps and installed opam install coq:io:system. My opam installation is at the default location ~/.opam. But still, I got an error about
Toplevel input, characters 53-67:
Error: The reference System.effects was not found in the current environment.
This is with either emacs/proofgeneral or coqide (8.4pl6, ubuntu 14.04). Does any one know how to fix the issue?
Here's the code which I copied into a file called hello_world.v and loaded into emacs/coqide:
Require Import Coq.Lists.List.
Require Import Io.All.
Require Import Io.System.All.
Require Import ListString.All.
Import ListNotations.
Import C.Notations.
(** The classic Hello World program. *)
Definition hello_world (argv : list LString.t) : C.t System.effects unit :=
System.log (LString.s "Hello world!").
-- Update ---
#gtzinos, I followed the readme in https://github.com/clarus/coq-hello-world. This time there was no complaint about System.effects, but there was a new error about Extraction.launch not found. I tried:
git clone https://github.com/clarus/coq-hello-world.git
cd coq-hello-world
./configure.sh && make
and got:
"coqc" -q -R src HelloWorld src/Main
File "/.../coq-hello-world/src/Main.v", line 32, characters 19-36:
Error: The reference Extraction.launch was not found in the current
environment.
I tried also to make in the extraction folder, but without success. Any pointers?
New versions of the coq:io and coq:io:system libraries were just released. Run:
opam update
opam upgrade
to make sure you have coq:io:system in version at least 2.3.0. Now Extraction.launch should be available. System.effects has been replaced by System.effect.
In scala it is common practice to stack package statements to allow shorter imports, but when I load a file using stacked packages into the scala ide and I attempt to use an import starting with the same organization I get a compiler error from what appears to be the presentation compiler. The code compiles fine in sbt outside of the IDE.
An example code snippet is as follows:
package com.coltfred
package util
package time
import com.github.nscala_time.time.Imports._
On the import I get the error object github is not a member of package com.coltfred.util.com.
If I move the import to a single line the error will go away, but we've used this practice frequently in our code base so changing them all to be single line package statements would be a pain.
Why is this happening and is there anything I can do to fix it?
Edit:
I used the eclipse-sbt plugin to generate the eclipse project file for this. The directory structure is what it should be and all of the dependencies are in the classpath.
Edit 2:
It turns out there was a file in the test tree of the util package (which should have been in the same package), but had a duplicate package statement at the top. I didn't check the test tree because it shouldn't affect the compilation of the main tree, but apparently I was wrong.
Not sure why the Scala IDE is not liking this, but you can force the import to start at the top level using _root_:
import _root_.com.github.nscala_time.time.Imports._
See if that avoids irritating the IDE.
This is a common annoyance that annoyed paulp into an attempt to fix it. His idea was that a dir that doesn't contribute class files shouldn't be taken as a package. If you can take util as scala.util, you should do so in preference to foo.util where that util is empty.
The util dir is the usual suspect, because who doesn't have a util dir lying around, and in particular, ./util?
apm#mara:~/tmp/coltfred$ mkdir -p com/coltfred/util/time
apm#mara:~/tmp/coltfred$ mkdir -p com/coltfred/util/com
apm#mara:~/tmp/coltfred$ vi com/coltfred/util/time/test.scala
apm#mara:~/tmp/coltfred$ scalac com/coltfred/util/time/test.scala
./com/coltfred/util/time/test.scala:5: error: object github is not a member of package com.coltfred.util.com
import com.github.nscala_time.time._
^
one error found
apm#mara:~/tmp/coltfred$ cat com/coltfred/util/time/test.scala
package com.coltfred
package util
package time
import com.github.nscala_time.time._
class Test
apm#mara:~/tmp/coltfred$
To debug, find out where the offending package is getting loaded from.