FsAutoComplete

The FsAutoComplete project (FSAC) provides a backend service for rich editing or 'intellisense' features for editors.

It can be hosted as command-line interface (stdio mode) or as http server (http mode), both using the same json protocol.

Currently it is used by:

It's based on:

FSharp.Compiler.Service for F# language info.
Dotnet.ProjInfo for project/sln management.
FSharpLint for the linter feature.

Required software

FsAutoComplete can run on .NET/mono or .NET Core.

FSAC .NET

on windows: Microsoft Build Tools 2015
on unix/mac: Required: Mono >= 5.12, Recommended: Mono >= 5.18

FSAC .NET Core

.NET Core Sdk
on unix/mac: Required: Mono >= 5.12, Recommended: Mono >= 5.18

Building and testing

Requirements:

.NET Core Sdk, see global.json for the exact version.
Mono 5.18 on unix/osx
Microsoft Build Tools 2013

There is a FAKE script who can be invoked with build.cmd/build.sh.

To build fsautocomplete binaries in ~/bin directory, do run build LocalRelease
To build, run all tests and create packages, do run build All

The integration tests use a simple strategy of running a scripted session with fsautocomplete and then comparing the output with that saved in the repository. This requires careful checking when the test is first constructed. On later runs, absolute paths are removed using regular expressions to ensure that the tests are machine-independent.

see test/FsAutoComplete.IntegrationTests/README.md for more info.

Troubleshooting

FileWatcher exceptions

You may see a stack trace finishing with System.IO.IOException: kqueue() error at init, error code = ’0’. This is due to a limitation in the number of filehandles that the Mono file watchers can keep open. Restarting FsAutoComplete or the hosting editor should help. If not, try setting export MONO_MANAGED_WATCHER=disabled in your ~/.bash_profile. Note that on OSX, this setting will only take effect if you launch emacs from the terminal.

Communication protocol

It is expected that the editor will launch this program in the background and communicate over a pipe. It is possible to use interactively, although due to the lack of any readline support it isn't pleasant, and text pasted into the buffer may not be echoed. As a result, use this only for very simple debugging. For more complex scenarios it is better to write another integration test by copying an existing one.

The available commands can be listed by running fsautocomplete --commands. Commands are all on a single line, with the exception of the parse command, which should be followed by the current text of the file to parse (which may differ from the contents on disk), and terminated with a line containing only <<EOF>>.

Data is returned as JSON. An example of a simple session is:

project "Test1.fsproj"

{"Kind":"project","Data":{"Files":["<absolute path removed>/Program.fs"],"Output":"<absolute path removed>/bin/Debug/Test1.exe"}}

parse "Program.fs"
module X =
    let func x = x + 1

    let val2 = X.func 2
    <<EOF>>

{"Kind":"INFO","Data":"Background parsing started"}

completion "Program.fs" 4 13

{"Kind":"completion","Data":["func"]}

Each response is exactly one line, which simplifies the application of a JSON parser. For further insight into the communication protocol, have a look over the integration tests, which have examples of all the features. Each folder contains one or more *Runner.fsx files which specify a sequence of commands to send, and *.json files, which contain the output.

Maintainers

The maintainers of this repository are:

The primary maintainer for this repository is Enrico Sada

Previous maintainers:

Robin Neatherway

TOTBWF/FsAutoComplete