vscode-ghc-mod

This exension exposes ghc-mod functionality to VS Code. It requires having ghc-mod installed. I installed v5.5.0 compiled by GHC 7.10.3 on Windows via cabal using these instructions and it is working. Hasn't been tested on Linux or OSX.

Symbol support requires having fast-tags or hasktags installed. For this reason, symbols are disabled by default. Change the configuration to enable it.

New Stack Support: I've tested it with simple stack projects (one stack.yaml/.cabal file in the root). Simply set "haskell.ghcMod.executablePath": "stack" in workspace or user settings (experimental and subject to change). Open an issue to help me improve it.

Features:

• check: Works best when configured to run "onSave" with autosave turned on. "onChange" is experimental and may cause problems with type, info, and "Peek/Go to definition" until a newer version of ghc-mod has improved support for map-file.
• type and info: Displayed when hovering the mouse over a symbol. See below for configuration.
• Go to definition: Use ctrl+click, f12, or right-click -> "Peek/Go to definition".
• Insert type: There is now a command to insert a type definition for a function on the line above. The cursor must be in the name of function so ghc-mod can find the type information for that symbol.
• Go to symbol: Use ctrl+shift+O or type @ in the command palette to see symbols in document.
• Show all symbols: Use ctrl+T or type # in the command palette followed by a search string to search for symbols across the entire workspace.

For linting, please use the haskell-linter extension.

Issues:

If you're having problems, enable logging and open the ghc-mod server output channel. If you think it is a bug instead of an environment issue, search for the issue or open a new one on github.

Pictures

Check

Example 1:

Example 2:

Info

Example 1:

Example 2:

Type

Go To Definition

Go To Symbol

Show All Symbols

Configuration:

The following options can be set in workspace or user preferences:

"haskell.ghcMod.maxNumberOfProblems": {
    "type": "number",
    "default": 100,
    "maximum": 100,
    "description": "Controls the maximum number of problems reported."
},
"haskell.ghcMod.executablePath": {
    "type": "string",
    "default": "ghc-mod",
    "description": "The full path to the ghc-mod executable, or 'stack' to use 'stack exec ghc-mod'."
},
"haskell.ghcMod.onHover": {
    "type": "string",
    "enum": [
        "info",
        "type",
        "fallback",
        "none"
    ],
    "default": "fallback",
    "description": "Controls the onHover behavior. 'info' will display ghc-mod info, 'type' will display ghc-mod type, 'fallback' will try info and fallback to type,and 'none' will disable onHover tooltips."
},
"haskell.ghcMod.check": {
    "type": "string",
    "enum": [
        "onSave",
        "onChange",
        "off"
    ],
    "default": "onSave",
    "description": "Controls whether ghc-mod check is enabled or not and when it triggers. For 'onSave' is recommended."
},
"haskell.ghcMod.logLevel": {
    "type": "string",
    "enum": [
        "none",
        "log",
        "info",
        "warn",
        "error"
    ],
    "default": "error",
    "description": "Controls the verbosity of logging. Logs can be seen in an output channel called 'ghc-mod server' or the chrome dev tools."
},
"haskell.symbols.provider": {
    "type": "string",
    "enum": [
        "none",
        "fast-tags",
        "hasktags"
    ],
    "default": "none",
    "description": "Selects a symbol provider."
},
"haskell.symbols.executablePath": {
    "type": "string",
    "default": "",
    "description": "Leave blank to use the default command for the selected provider (i.e. 'fast-tags'), otherwise set the full path to the executable. Extension may behave unexpectedly if the symbol provider setting is for a different command than the path provided."
}

Changelog

1.2.0

• Closed #35: Added experimental support for stack projects. Setting haskell.ghcMod.executablePath to stack will now use stack exec to execute ghc-mod.

1.1.1

• Closed #51: Non-actionable errors no longer use window.showErrorMessage. Errors are still shown in the output channel under "ghc-mod server".

1.1.0

• Closed #41: Fixed crashes on certain symbols (-1, -n, etc.). Thanks to @danstiner for the fix.
• Closed #43: Added "Haskell Syntax Highlighting" as an extension dependency.
• Closed #40: Logging uses output channel
• Closed #37: When ghc-mod cannot be started, error prompt contains information and actions to change the user or workspace settings.

1.0.1

• Fixed path to uri issue on non-windows systems.

1.0.0

• Added "Go to symbol"/"Show all symbols" support based on fast-tags or hasktags. Thanks to @archaeron for starting the feature.

0.3.0

• Added "insert type" command. Thanks to @theor for the pull request.

0.2.5

• Fixed a ghc-mod crash on longer sets of comment dashes such as -----------.

0.2.4

• Setting "haskell.ghcMod.check": "onChange" will cause the extension to use map-file. This removes the need to save the file but can cause problems in current ghc-mod (5.5.0) and lower, but will hopefully fixed in an upcoming released so I've prepared for it now.
• Fixed a ghc-mod crash on -> and --.

0.2.2

• Fixed a ghc-mod crash bug on mac when word is empty string (thanks @slepher).

0.2.0

• Breaking: Files must be saved (auto-save is your friend).
• Type and Info tooltips are now more colorful (treated as code).
• Go To Definition works.