ghc-imported-from
For a given Haskell source file, determine the path to the Haddock documentation for a symbol at a particular line/col location.
Example: on the file src/Main.hs,
ghc-imported-from haddock-url src/Main.hs Main getArgs 69 13
says
SUCCESS: file:///home/carlo/opt/ghc-7.6.3_build/share/doc/ghc/html/libraries/base-4.6.0.1/System-Environment.html
since the usage of getArgs at line 160, column 13, is from the System.Environment module.
Difficulties arise because some symbols are exported from a certain
package but defined in another, for example String is defined in
GHC.Base but is exported from the standard prelude, the module
Prelude. There are other cases to deal with including qualified
imports, selective imports, imports with hidden components, etc.
Preference is given to any locally available Haddock documentation,
and then to the generic url at hackage.org.
Beware
You may have to run
cabal build
or
cabal repl
in a project directory to sort out some of the dist/build/autogen
files. At the moment ghc-imported-from has no functionality to
do this boot process automatically. To run cabal repl you might need
the latest Cabal from [https://github.com/haskell/cabal](https://github.com/haskell/cabal).
If you see
<command line>: cannot satisfy -package hspec
(use -v for more information)
then you may need the hspec and/or doctest packages:
cabal install hspec doctest
Feedback and pull requests most welcome!
Install
ghc-imported-from
Install into ~/.cabal:
git clone https://github.com/carlohamalainen/ghc-imported-from
cd ghc-imported-from
cabal install
Or, install into a sandbox:
git clone https://github.com/carlohamalainen/ghc-imported-from
cd ghc-imported-from
./build_in_sandbox.sh
Either way, ensure that ghc-imported-from and fake-ghc-for-ghc-imported-from are in the current PATH.
Tests
Run the tests using cabal:
cabal test
If the tests hang, check that your version of Cabal/cabal-install has this
fix: https://github.com/haskell/cabal/issues/1810
ghcimportedfrom-vim
For Vim users,
follow the instructions at
[https://github.com/carlohamalainen/ghcimportedfrom-vim](https://github.com/carlohamalainen/ghcimportedfrom-vim)
to install the Vim plugin.
ghc-imported-from-el
For Emacs users, David Christiansen has written ghc-imported-from-el.
Usage
See the tests subdirectory for some examples. Or load your favourite Haskell project and hit F4.
Or watch the screencast (be sure to set 720p HD and then fullscreen):
[https://www.youtube.com/watch?v=7yO_VGCWMu8](https://www.youtube.com/watch?v=7yO_VGCWMu8)
Notes
ghc-imported-from uses both GHC and ghc-pkg, which
accept arguments in differing formats. For example GHC takes
-package-db while ghc-pkg takes --package-db=. For more
details: http://www.vex.net/~trebla/haskell/sicp.xhtml
Debugging
To see the GHC options that have been automatically detected, change into your project's directory and run:
$ cd ~/ghc-imported-from
$ cabal repl --with-ghc=fake-ghc-for-ghc-imported-from
Preprocessing library ghc-imported-from-0.2.0.2...
--interactive -fbuilding-cabal-package -O0 -outputdir dist/build -odir dist/build -hidir dist/build -stubdir dist/build -i -idist/build -i. -idist/build/autogen -Idist/build/autogen -Idist/build -optP-include -optPdist/build/autogen/cabal_macros.h -package-name ghc-imported-from-0.2.0.2 -hide-all-packages -no-user-package-db -package-db /home/user/ghc-imported-from/.cabal-sandbox/x86_64-linux-ghc-7.6.3-packages.conf.d -package-db dist/package.conf.inplace -package-id Cabal-1.16.0-c6e09e008cd04cf255c1ce0c59aba905 -package-id base-4.6.0.1-8aa5d403c45ea59dcd2c39f123e27d57 -package-id containers-0.5.0.0-ab1dae9a94cd3cc84e7b2805636ebfa2 -package-id directory-1.2.0.1-91a788fd88acd7f149f0f10f5f1e23f2 -package-id filepath-1.3.0.1-b12cbe18566fe1532a1fda4c85e31cbe -package-id ghc-7.6.3-18957ddbb817289f604552aa2da2e879 -package-id ghc-mod-4.1.0-a87501f2667239b3f0bef3e0f3753496 -package-id ghc-paths-0.1.0.9-3817f31ae510ed3b58554933ea527b74 -package-id ghc-syb-utils-0.2.1.2-bf72c1e71339c52f0af404a12449c9d2 -package-id mtl-2.2.0.1-ef91e0abcf7a4fb581ecb7fe83cdcba1 -package-id process-1.1.0.2-76e05340eb66705981411022731ca84a -package-id safe-0.3.4-ba52ca348aecad429ba90450e3aba4c4 -package-id syb-0.4.1-9469ffdd9c6a7ebbf035421c915a08ee -package-id transformers-0.4.1.0-42810d723884ebf2a2dd638e5b22e523 -XHaskell2010 Language.Haskell.GhcImportedFrom Language.Haskell.GhcImportedFrom.UtilsFromGhcMod Language.Haskell.GhcImportedFrom.Types -Wall
Alternatives
As far as I know the only alternative is the fpco/hoogle-doc function in
[https://www.fpcomplete.com/page/api](https://www.fpcomplete.com/page/api). Or try Ctrl-i
in the web version of FP Complete.
