Have you ever needed to get information from a cabal file in a shell
script? Now you can! cabal-info exposes a simple command-line
interface to the cabal file format.
There is also a library interface, to solve tasks based on searching for a .cabal file and then doing something with it. For example, to find a .cabal file, get the path to every module it exposes, and run doctest on those:
import Test.Doctest (doctest)
import Cabal.Info (getLibraryModules)
main :: IO ()
main = getLibraryModules >>= doctest . either (const []) idThe library documentation of the latest developmental version is available online.
Usage: cabal-info [--cabal-file FILE] [-f|--flags FLAGS] [-a|--arch ARCH]
[-o|--os OS] [FIELD]
Print fields from a cabal file.
Available options:
-h,--help Show this help text
--cabal-file FILE The cabal file to use. If unspecified, the first one
found in this directory is used instead.
-f,--flags FLAGS Force values for the given flags in Cabal
conditionals in the .cabal file. E.g. --flags="debug
-usebytestrings" forces the flag "debug" to true and
the flag "usebytestrings" to false.
-a,--arch ARCH The architecture to use when expanding conditionals.
Allowed values are (case insensitive): i386, x86_64,
ppc, ppc64, sparc, arm, mips, sh, ia64, s390, alpha,
hppa, rs6000, m68k, vax, javascript.
-o,--os OS The operating system to use when expanding
conditionals. Allowed values are (case insensitive):
linux, windows, osx, freebsd, openbsd, netbsd,
dragonfly, solaris, aix, hpux, iric, halvm, ios,
ghcjs.
FIELD This is in the format [section:]field, where the
section can be the name of a source repository,
executable, test suite, or benchmark. If no field is
given, then the file is pretty-printed, with any
flags applied.
Here's a simple cabal file:
name: HUnit
version: 1.1.1
synopsis: A unit testing framework for Haskell
homepage: http://hunit.sourceforge.net/
category: Testing
author: Dean Herington
license: BSD3
license-file: LICENSE
cabal-version: >= 1.10
build-type: Simple
library
build-depends: base >= 2 && < 4
exposed-modules: Test.HUnit.Base, Test.HUnit.Lang,
Test.HUnit.Terminal, Test.HUnit.Text, Test.HUnit
default-extensions: CPP
Here are some simple queries:
$ cabal-info name
HUnit
$ cabal-info build-depends
base >=2 && <4
Multi-value fields are displayed with each value on a new line.
$ cabal-info exposed-modules
Test.HUnit.Base
Test.HUnit.Lang
Test.HUnit.Terminal
Test.HUnit.Text
Test.HUnit
Now let's look at a more complex example:
name: TestPackage
version: 0.0
synopsis: Package with library and two programs
license: BSD3
author: Angela Author
build-type: Simple
cabal-version: >= 1.2
library
build-depends: HUnit
exposed-modules: A, B, C
executable program1
main-is: Main.hs
hs-source-dirs: prog1
other-modules: A, B
executable program2
main-is: Main.hs
hs-source-dirs: prog2
other-modules: A, C, Utils
We can use the name of the executable to extract information from each:
$ cabal-info program1:hs-source-dirs
prog1
$ cabal-info program2:hs-source-dirs
prog2
There are a few special cases:
- "flag", "executable", "testsuite", "benchmark", and "repository" refer to the name of the first flag/executable/etc.
- "flags", "executables", "testsuites", "benchmarks", and "repositories" refer to list of names of the flags/executables/etc.
- "main-is" refers to the main-is field of the first executable.
- "upstream" refers to the location of the head source repository.
For example:
$ cabal-info main-is
Main.hs
$ cabal-info executable
program1
We can also deal with flags:
Name: Test1
Version: 0.0.1
Cabal-Version: >= 1.2
License: BSD3
Author: Jane Doe
Synopsis: Test package to test configurations
Category: Example
Flag Debug
Description: Enable debug support
Default: False
Flag WebFrontend
Description: Include API for web frontend.
-- Cabal checks if the configuration is possible, first
-- with this flag set to True and if not it tries with False
Library
Build-Depends: base
Exposed-Modules: Testing.Test1
Extensions: CPP
if flag(debug)
GHC-Options: -DDEBUG
if !os(windows)
CC-Options: "-DDEBUG"
else
CC-Options: "-DNDEBUG"
if flag(webfrontend)
Build-Depends: cgi > 0.42
Other-Modules: Testing.WebStuff
Executable test1
Main-is: T1.hs
Other-Modules: Testing.Test1
Build-Depends: base
if flag(debug)
CC-Options: "-DDEBUG"
GHC-Options: -DDEBUG
The "debug" flag defaults to false, and "webfrontend" to true:
$ cabal-info test1:cc-options
$ cabal-info -fdebug test1:cc-options
-DDEBUG
$ cabal-info build-depends
base -any && -any
cgi >0.42
$ cabal-info -f-webfrontend build-depends
base -any && -any
Finally, we can pretty-print an entire cabal file, with flags applied. This is useful for seeing the effects of different combinations of flags:
$ cabal-info
name: Test1
version: 0.0.1
build-depends: base -any && -any
, cgi >0.42
license: BSD3
author: Jane Doe
synopsis: Test package to test configurations
category: Example
library
exposed: True
exposed-modules: Testing.Test1
build-depends: base -any
, cgi >0.42
other-modules: Testing.WebStuff
hs-source-dirs: .
extensions: CPP
buildable: True
executable test1
main-is: T1.hs
build-depends: base -any
other-modules: Testing.Test1
hs-source-dirs: .
buildable: True
$ cabal-info -f"debug -webfrontend"
name: Test1
version: 0.0.1
build-depends: base -any && -any
, cgi >0.42
license: BSD3
author: Jane Doe
synopsis: Test package to test configurations
category: Example
library
exposed: True
exposed-modules: Testing.Test1
build-depends: base -any
, cgi >0.42
other-modules: Testing.WebStuff
hs-source-dirs: .
extensions: CPP
buildable: True
ghc-options: -DDEBUG
cc-options: -DDEBUG
executable test1
main-is: T1.hs
build-depends: base -any
other-modules: Testing.Test1
hs-source-dirs: .
buildable: True
ghc-options: -DDEBUG
cc-options: -DDEBUG
Bug reports, pull requests, and comments are very welcome!
Feel free to contact me on GitHub, through IRC (#haskell on freenode), or email ([email protected]).