What is a .FS file?
The .fs extension is used by both F# source code and GPU fragment shaders.
F# source
- What it is
- An F# source file - .NET functional code. Analyser opens it as source.
- How to tell it apart
- Both are text; Analyser opens .fs as source.
- Did you know
- F# brought OCaml-style functional programming to .NET; its name nods both to 'functional' and to the ML language family it descends from.
- F# was designed by Don Syme at Microsoft Research in Cambridge, whose earlier work bringing generics to .NET also shaped C#.
- F#'s asynchronous workflows, shipped around 2007, directly inspired the async/await keywords later adopted by C# and many other languages.
GPU fragment shader
- What it is
- A GLSL / HLSL fragment (pixel) shader. Analyser opens it as source.
- How to tell it apart
- Both are text; Analyser opens .fs as source.
- Did you know
- Because .fs is only a naming convention, the same shader code also circulates as .frag files or embedded strings inside programs.
- OpenGL calls it a 'fragment' rather than 'pixel' shader because it runs on candidate fragments that depth or stencil tests may still discard before any pixel is drawn.
- Direct3D calls the very same stage a 'pixel shader', one of several naming splits between Microsoft's HLSL and the OpenGL GLSL world.
- Depth of analysis
- .FS is an identification-grade format: Analyser recognises it from its bytes and decodes the header metadata it carries, rather than opening it in a full viewer. Formats that do get a full viewer are marked "Full" on the formats page.
- Open a .FS file
- Drag a .FS file onto the Analyser home page (or tap to pick one). It is identified entirely in your browser - nothing is uploaded, there is no account, and it works offline once installed.