spacemacs/layers/+lang/elm/README.org

Elm layer

• Description
• Install
  • Layer
  • Elm Platform
    • OS X and Windows installers
    • Universal installer using npm
    • Source code
  • elm-oracle
• Basic usage tips
  • Compilation
  • Reactor
• Key bindings
  • elm-make
  • elm-repl
  • elm-reactor
  • elm-package
    • package list buffer
  • elm-oracle

Description

This layer adds support for Elm.

It relies on elm-mode and flycheck-elm to provide the following features:

• Syntax highlighting.
• Intelligent indentation
• Auto-completion integration for company (default) or auto-complete modes, with using elm-oracle
• Syntax checking support using flycheck
• Integration with elm-make
• Integration with elm-repl
• Integration with elm-reactor
• Integration with elm-package

Install

Layer

To use this configuration layer, add it to your ~/.spacemacs. You will need to add elm to the existing dotspacemacs-configuration-layers list in this file.

Elm Platform

The elm-platform is a bundle of tools, including the elm-compiler, elm-make, elm-reactor, elm-repl and elm-package.

Depending on the method of installation, the elm-mode package would need to be able to access commands such as elm-reactor or elm-make.

OS X and Windows installers

Official installers for these operating systems are available from: http://elm-lang.org/install">http://elm-lang.org/install

Universal installer using npm

A npm based installer is available to, and provides pre-compiled binaries for certain operating system and architectures.

  npm install --global elm

Also, note that you might need to set the ELM_HOME environment variables to the corresponding directory created by the installer.

OS X Users facing problems with elm-reactor failing to properly install or run, see this issue https://github.com/kevva/elm-bin/issues/28">https://github.com/kevva/elm-bin/issues/28.

Source code

To build from source, see instructions here: https://github.com/elm-lang/elm-platform">https://github.com/elm-lang/elm-platform

elm-oracle

elm-oracle can be used to show type signatures and docs for tokens under the cursor and provide support for auto-completion, but it is not part of the standard elm-platform.

Both the "company" and "auto-complete" backends are supported, but this layer is configured with company.

To install elm-oracle, install node.js and npm, then run this command:

  npm install -g elm-oracle

Basic usage tips

Compilation

To control the name of the compiled JavaScript file, use SPC m c B instead of SPC m c b. This will overwrite the --output parameter of elm-make to [buffer-name].js instead of the default.

Reactor

elm-reactor is an interactive development tool, used to develop and debug Elm programs. It will automatically compile an Elm program, and run it in the browser, with editor agnostic support for hot-swapping and time-travel debugging.

To preview Main.elm, press C-c C-m (or SPC m R m). Alternatively, to preview from buffer, press C-u C-c C-n (or SPC m R n). To preview in debug mode, prefix with C-u (or SPC u).

By default, elm-reactor with launch with its own generated index.html. To use a custom html, you'd need to load the debuger excplictly and use an http daemon to serve your custom file.

If needed, default values for host and port used by for the elm-reactor server can be controlled by passing in these variables in your ~/.spacemacs:

  (elm :variables
       elm-reactor-port "3000"          ; default 8000
       elm-reactor-address "0.0.0.0") ; default 127.0.0.1

Key bindings

elm-make

Key Binding	Description
SPC m c b	elm-compile-buffer
SPC m c B	spacemacs/elm-compile-buffer-override-output
SPC m c m	elm-compile-main

elm-repl

Key Binding	Description
SPC m s i	elm-repl-load
SPC m s f	send current function to REPL
SPC m s F	send current function to REPL and focus it in insert state
SPC m s r	send current region to REPL
SPC m s R	send current region to REPL and focus it in insert state

elm-reactor

Key Binding	Description
SPC m R n	elm-preview-buffer
SPC m R m	elm-preview-main

elm-package

Key Binding	Description
SPC m p i	elm-import
SPC m p c	elm-package-catalog
SPC m p d	elm-documentation-lookup

package list buffer

Key Binding	Description
g	elm-package-refresh
n	elm-package-next
p	elm-package-previous
v	elm-package-view
m	elm-package-mark
u	elm-package-unmark
x	elm-package-install
q	quit-window

elm-oracle

Key Binding	Description
SPC m h t	elm-oracle-type-at-point