Reload Haskell Web IDE

This is a very basic IDE for Haskell, running as a local web server and a web front end.

Technical choices

• Server is WAI/Scotty, exposes a REST API.
• Client is Javascript/Polymer, trying to use material design components
• Uses ghcid to perform on the fly validation
• Uses a WebSocket to send back validation results, etc.
• Changes to the files are persisted to disk automatically (no manual save)
• Uses the ACE web editor
• Starts the browser window automatically, closes the server when the window is closed, like Network.WAI.Launcher does (but I had to copy and modify the code since it doesn't work well if you have multiple HTML files, and of course since we're showing HTML to edit).

Building

• You'll need npm and bower to install the dependencies (run bower update in the web directory), since all the dependent components are NOT present in the github repo.
• The server bit can be built via stack build

Current functionality

• Add/Delete files and folders
• Reload ghcid on file content change
• Supports Cabal or Stack
• Display errors as an (ugly) menu and annotations in the editor
• Build, Test and Benchmark
• Run arbitrary commands (stack exec something, etc.)
• GHCi info: inside the editor, on a Haskell file, press Ctrl-I (Command-I on Mac) to get the info from ghci in a tooltip. Click again in the editor to hide the tooltip.
• Format via stylish-haskell or arbitrary command

Running

Start the executable from the root directory of your Haskell project (where the cabal and stack files reside). You can pass the port to listen to as an argument (default is 8080).

Configuration

Create a file called "reload.json" at the folder root. This is a JSON file. For the moment, is only supported something like:

{
  "editor" : {
    "theme" : "XCode"
    ,"actions": {
      "format" : "/path/to/stylish-haskell"
    }
  },
  "actions" : {
    "run1" : "stack exec echo hello"
  }
}

editor.theme is the short name for the ACE editor theme you want to use. Internally, we convert to lower case, replace spaces by underscores and prefix by ace/theme. editor.actions.format is the command used to format Haskell source files. If not specified, defaults to stylish-haskell, which of course must be in the path.

actions define some actions that will be executed in the root folder. If the key is build it defines the command to run when you choose Build in the menu (default to cabal|stack build). You can pass any extra options there. If the key is test it defines the command to run when you choose Build and Test in the menu (default to cabal|stack test). If the key is bench it defines the command to run when you choose Build and Benchmark in the menu (default to cabal|stack bench). If the key is something else, it will appear in the list shown when you choose Run... in the menu, letting you specify any command you'd like to run.

Screenshots

The IDE with the XCode theme, and a silly error:

Running build and test shows the output in a editor as well: