Fsharp on queil.net

F# - an introduction for my colleagues

Wed, 14 Dec 2022 03:20:00 +0000

This article was originally published on the Account Technologies Tech Blog.

Motivation ¶

Having used quite a few programming languages in numerous projects(C#, Powershell, TypeScript, Groovy, and others), my favourite so far is F#. In this article, I want to present to you the unique traits of F# as a pragmatic functional-first language. Hopefully, this article is a mild and concise introduction to F# for people using other languages.

What is F# ¶

F# is a pragmatic general-purpose programming language. Its core design goals were:

Gmox Grpc Mock Server

Sun, 26 Dec 2021 13:06:58 +0000

TLDR: I created Gmox - a .NET-friendly gRPC mock server.

What is Gmox ¶

It is a gRPC mock server similar to grip-mock but written in F# and distributed as a dotnet cli tool and a dotnet template.

Why create one if other implementations already exist ¶

I wanted to create something easy to use for (my fellow- and all other) .NET developers.

I had the following scenarios in mind:

Development - enable developers to quickly spin up a mock server instance from local proto files.
Testing - enable testers to deploy a mock server as a part of a test scenario and control it during a test run.

Also I had the following requirements:

Dependency Trees With Fable and Sutil

Sat, 04 Dec 2021 15:04:33 +0000

Motivation ¶

One of my colleagues has recently mentioned they can hardly follow the dependency tree of YAML-configured systems like kustomize or GitLab CI. Both mentioned technologies enable configuration reuse via composition and inheritance. Obviously the reuse comes with an increased complexity which may be overwhelming for a newcomer. To lower the learning curve I wanted to create a tool that would allow an ad-hoc tree traversal and visualisation. I am excited as it requires reaching beyond my comfort zone. Straight to the realm of front-end.

Embedding F# Compiler: Fsc-Host NuGet

Sat, 16 Oct 2021 12:12:10 +0100

I have created a NuGet package that lets you easily use F# scripting in your apps.

NuGet: https://www.nuget.org/packages/Queil.FSharp.FscHost
Source: https://github.com/queil/fsc-host

What is this all about? ¶

In two previous posts (1, 2) I showed you how to host the F# compiler in your own applications. This time I wanted to reveal the result of those experiments. I wanted to enable F# scripting in a few of my apps. This requirement made me create the Fsc Host project. The goal was to create a light-weight reusable abstraction over FSharp.Compiler.Service focused on compiling scripts and consuming them by the hosting application. The NuGet package is available here. The project is still in the experimental phase (version 0) so the API and available features may change, (and the changes may be breaking so bear that in mind before using it in your projects).

Embedding F# Compiler: NuGet References

Fri, 04 Jun 2021 08:52:26 +0100

UPDATE: If you are looking for a ready to use solution please check out my fsc-host NuGet package. Also I wrote a blog post about it.

Intro ¶

In the previous post I showed how to extend an F# application with scripting capabilities. This time I want to extend the previous example with the #r directive support and resolving NuGet dependencies.

How to ¶

On high level we need to extract NuGet packages information from the script and pass it to the compiler as additional arguments. Before compiling we also need to dynamically load the referenced dlls to the host application. I first took the naive approach of parsing and extracting the directives from AST and feeding them into FSharpDependencyManager. It worked to an extent. Luckily, FsChecker comes with a built-in solution. We can use GetProjectOptionsFromScript and subsequently ParseAndCheckProject methods. That way we can retrieve DependencyFiles and extract resolved dlls’ paths.

Embedding F# Compiler

Sat, 29 May 2021 10:03:24 +0100

UPDATE: If you are looking for a ready to use solution please check out my fsc-host NuGet package. Also I wrote a blog post about it.

Motivation ¶

Embedded scripting is one of the ways of providing flexibility to compiled applications. It is not free from problems (performance penalty, security issues, additional tooling is required). But if your goal is a ceremony-free flexibility for the end-user then scripting is a very robust way¹ . F# comes with great capabilities in this area. I want to show you how you can extend your otherwise statically compiled program with scripting.

Give it a try: Safe

Wed, 16 May 2018 07:46:11 +0100

Intro ¶

I’ve recently learnt about the SAFE Stack. It’s F# all the way from the client to the server side. It’s a fantastic news for back-end people (knowing F#). There is no need of learning intricacies of JavaScript. You can focus on productivity instead. In this post I just want to show you how quickly you can start developing.

First SAFE app ¶

Prerequisites ¶

.Net Core 2, Node.js, Yarn. Make sure you’ve got it all. Then just open shell and let’s type.

Finding references in C# code with Roslyn and F#

Tue, 20 Feb 2018 19:58:29 +0000

Introduction ¶

The most of .NET developers use Roslyn (the .NET Compiler) everyday. But apart from compiling code it comes with a versatile APIs used for syntax highlighting, analyzers, navigation tools just to name the most typical ones. I want to show you how to use it in your own tools. This time I want a tiny tool that finds all usages of a class¹ in a solution².

Let’s code ¶

I picked F# as my language of choice for this post. The code is easily translatable to C# though. All the code from the article you can access here.