FSharp.Compiler.Service

The FSharp.Compiler.Service package is a component derived from the F# compiler source code that exposes additional functionality for implementing F# language bindings, additional tools based on the compiler or refactoring tools. The package also includes dynamic execution of F# code that can be used for embedding F# scripting into your applications.

Available services

The project currently exposes the following services that are tested & documented on this page. The libraries contain additional public API that can be used, but is not documented here.

F# Language tokenizer - turns any F# source code into a stream of tokens. Useful for implementing source code colorization and basic tools. Correctly handle nested comments, strings etc.
Processing SyntaxTree - allows accessing the syntax tree. This represents parsed F# syntax without type information and can be used to implement code formatting and various simple processing tasks.
Working with resolved symbols - many services related to type checking return resolved symbols, representing inferred types, and the signatures of whole assemblies.
Working with resolved expressions - services related to working with type-checked expressions and declarations, where names have been resolved to symbols.
Using editor services - expose functionality for auto-completion, tool-tips, parameter information etc. These functions are useful for implementing F# support for editors and for getting some type information for F# code.
Working with project-wide analysis - you can request a check of an entire project, and ask for the results of whole-project analyses such as find-all-references.
Hosting F# interactive - allows calling F# interactive as a .NET library from your .NET code. You can use this API to embed F# as a scripting language in your projects.
Hosting the F# compiler - allows you to embed calls to the F# compiler.
File system API - the FSharp.Compiler.Service component has a global variable representing the file system. By setting this variable you can host the compiler in situations where a file system is not available.

NOTE: The FSharp.Compiler.Service API is subject to change when later versions of the nuget package are published

The Public Surface Area

We are in the process of cleaning up the surface area of FCS to allow it to be fully binary compatible going forward.

The full current surface area can be seen at: https://fsharp.github.io/fsharp-compiler-docs/reference/index.html

The API is generally designed with F#/.NET design conventions (e.g. types in namespaces, not modules, no nesting of modules etc.) and we must continue to iterate to make this so.

The parts of the compiler under FSharp.Compiler.AbstractIL.* are "incidental" and not really designed for public use apart from the hook for JetBrains Rider (Aside: In theory all these other parts could be renamed to FSharp.Compiler though there's no need to do that right now). These internal parts tend to be implemented with the "module containing lots of stuff in one big file" approach for layers of the compiler.

Basics - Syntax, Text and Diagnostics

Tokenization

FSharp.Compiler.Tokenization

Symbols and Code Analysis

Projects using the F# Compiler Services

Some of the projects using the F# Compiler Services are:

F# in Visual Studio
F# in Visual Studio for Mac
FsAutoComplete
F# in JetBrains Rider
F# in .NET Interactive Notebooks
Fantomas - Source code formatting for F#
FSharpLint - Lint tool for F#
Fable - F# to JavaScript Compiler and more
WebSharper - F# full-stack web framework

Older things:

FsReveal - FsReveal parses markdown and F# script file and generate reveal.js slides
Elucidate - Visual Studio extension for rich inlined comments using MarkDown
FSharp.Formatting - F# tools for generating documentation (Markdown processor and F# code formatter)
FAKE - "FAKE - F# Make" is a cross platform build automation system

Contributing and copyright

The F# source code is copyright by Microsoft Corporation and contributors.