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| config.el | ||
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| README.md | ||
Haskell contribution layer for Spacemacs
Table of Contents
Description
This layer adds support for the Haskell language.
Features:
- auto-completion with company-ghc,
- auto-indentation with hi2.
This layer is in construction, it needs your contributions and bug reports.
Install
Layer
To use this contribution add it to your ~/.spacemacs
(setq-default dotspacemacs-configuration-layers '(haskell))
Cabal packages
This layer requires some cabal packages:
ghc-modhlintstylish-haskell
To install them, use the following command:
cabal install stylish-haskell hlint ghc-mod
Next Emacs needs to know where to find these binaries, you can locate them with the following shell command:
dirname $(which ghc-mod)
Then you have to add this path to your system $PATH (preferred):
export PATH=~/.cabal/bin/:$PATH
or to the Emacs exec-path variable in the dotspacemacs/init function of
your .spacemacs file:
(add-to-list 'exec-path "~/.cabal/bin/")
Note: it is important to add the path in the dotspacemacs/init function,
so that the path is added before any layers is loaded.
OS X
Note that emacs.app for OS X does not pick up $PATH from ~/.bashrc or
~/.zshrc when launched from outside a terminal.
Optional extras
The Haskell layer supports some extra features that can be enabled through layer variables.
GHCi-ng support
ghci-ng adds some nice features to haskell-mode, and is supported in
Spacemacs by a layer variable:
Follow the instructions to install ghci-ng (remember to add :set +c
in ~/.ghci, next set the layer variable:
;; List of configuration layers to load.
dotspacemacs-configuration-layers
'(company-mode
git
(haskell :variables haskell-enable-ghci-ng-support t))
Once ghci-ng is enabled, two of the old keybindings are overriden with improved versions from ghci-ng, and a new keybinding available:
Key Binding | Description
----------------------|------------------------------------------------------------ SPC m t | gets the type of the identifier under the cursor or for the active region SPC m g g | go to definition SPC m u | finds uses of identifier
structured-haskell-mode
structured-haskell-mode, or shm, replaces hi2 (and any other
Haskell-indentation modes) and adds some nice functionality.
To enable shm, run cabal install structured-haskell-mode and set the layer
variable:
;; List of configuration layers to load.
dotspacemacs-configuration-layers '(company-mode (haskell :variables haskell-enable-shm-support t) git)
After shm has been enabled, some of the evil normal-mode bindings are overridden:
Key Binding | Description
----------------------|------------------------------------------------------------
D | shm/kill-line
R | shm/raise
P | shm/yank
( | shm/forward-node
) | shm/backward-node
For a nice visualization of these functions, please refer to the github page for structured-haskell-mode.
hindent
hindent is an extensible Haskell pretty printer, which let's you
reformat your code. You need to install the executable with cabal install hindent; to enable it set:
;; List of configuration layers to load.
dotspacemacs-configuration-layers
'(company-mode
git
(haskell :variables haskell-enable-hindent-support t))
By default it uses the style called fundamental, if you want to use
another, johan-tibell, run M-x customize-variable hindent-style.
Key bindings
All Haskell specific bindings are prefixed with SPC m
Haskell source code:
Haskell commands:
Top-level commands are prefixed by SPC m:
Key Binding | Description
----------------------|------------------------------------------------------------ SPC m t | gets the type of the identifier under the cursor SPC m i | gets information for the identifier under the cursor SPC m g g | go to definition or tag SPC m f | format buffer using haskell-stylish SPC m F | format declaration using hindent (if enabled)
Documentation commands:
Documentation commands are prefixed by SPC m h
Key Binding | Description
----------------------|------------------------------------------------------------ SPC m h d | find or generate Haddock documentation for the identifier under the cursor SPC m h h | do a Hoogle lookup SPC m h y | do a Hayoo lookup
Cabal commands:
Cabal commands are prefixed by SPC m c:
Key Binding | Description
----------------------|------------------------------------------------------------
SPC m c a | cabal actions
SPC m c b | build the current cabal project, i.e. invoke cabal build
SPC m c c | compile the current project, i.e. invoke ghc
SPC m c v | visit the cabal file
Debug commands:
Debug commands are prefixed by SPC m d:
Key Binding | Description
----------------------|------------------------------------------------------------ SPC m d d | start debug process, needs to be run first SPC m d b | insert breakpoint at function SPC m d n | next breakpoint SPC m d N | previous breakpoint SPC m d B | delete breakpoint SPC m d c | continue current process SPC m d a | abandon current process SPC m d r | refresh process buffer
REPL commands:
REPL commands are prefixed by SPC m s:
Key Binding | Description
----------------------|------------------------------------------------------------ SPC m s b | load or reload the current buffer into the REPL SPC m s c | clear the REPL SPC m s s | show the REPL SPC m s S | show and switch to the REPL
Cabal files:
Key Binding | Description
----------------------|------------------------------------------------------------ SPC m d | add a dependency to the project SPC m b | go to benchmark section SPC m e | go to executable section SPC m t | go to test-suite section SPC m m | go to exposed modules SPC m l | go to libary section SPC m n | go to next subsection SPC m p | go to previous subsection SPC m N | go to next section SPC m P | go to previous section SPC m f | find or create source-file under the cursor