/fp-in-csharp

Functional Programming in C#

Primary LanguageJavaScript

Functional Programming in C#

Run the decks

NOTE: you can use yarn or npm commands interchangeably but do yourself a favor and install yarn globally npm i yarn -g and save some time!

  • clone this repo
  • cd deck
  • yarn install
  • Start deck for Part 1 yarn run part1
  • Start deck for Part 2 yarn run part2

Export the decks as PDF

  • Export deck for Part 1 yarn run pdf deck1.pdf
  • Export deck for Part 2 yarn run pdf deck2.pdf

Examples

To run each example, move into its respective folder and run dotnet run.

Part 1

  • examples/Code/FPinCSharp.Example1
    • Employee directory application written in an imperative way
  • examples/Code/FPinCSharp.Example2
    • Fixing Employee directory bugs by avoiding mutation
  • examples/Code/FPinCSharp.Example3
    • Fixing Employee directory bugs caused due to having partial functions and unexpected nulls by utilizing Option

Part 2

  • examples/Code/FPinCSharp.Example4
    • Leverage Either effect to encode application errors in a functional way
  • examples/Code/FPinCSharp.LINQSyntax
    • Introduction to C# LINQ syntax which is a convenient syntax for chaining effectful functions
  • examples/Code/FPinCSharp.Example5
    • Social media profile generation by composing sequential Tasks using a Monadic approach
  • examples/Code/FPinCSharp.Example6
    • Social media profile generation by composing parallel Tasks using an Applicative approach
  • examples/Code/FPinCSharp.Traversables
    • Working with lists of elevated values and using Sequence and Traverse functions
  • examples/Code/FPinCSharp.Example7
    • Generating many Social media profiles in parallel leveraging Sequence from Traversables, the whole request fails if any fail
  • examples/Code/FPinCSharp.Example8
    • Generating many Social media profiles in parallel and ignoring the failed requests and collected the successfully results only

What to expect in Part 3

  • More Advanced, real world examples of working with Try, TryAsync, Traversables

    • examples/Code/FPinCSharp.Traversables
    • examples/Code/FPinCSharp.Example8

  • Pattern Matching

    • Pattern matching in C#
    • Functional ways of application development using Pattern Matching (creating your own DSL for making a small metrics service)
      • examples/LINQPad/pattern-matching-vs-polymorphism
    • Limitations of Pattern Matching and Problems of using PM as a replacement to Polymorphism in C#

  • Ad-Hoc Polymorphism and C#

    • Types of polymorphism
      • examples/LINQPad/subtype-polymorhism.linq
    • Ad-Hoc Polymorphism
      • examples/LINQPad/ad-hoc-polymorphism.linq
      • examples/LINQPad/ad-hoc-polymorhism-using-extention-methods-in-csharp.linq
    • Extension methods as the closest thing in C# for achieving Ad-Hoc Polymorphism
    • Higher Kinded Types

  • Lenses and ways of working with nested complex immutable types

    • examples/Code/FPinCSharp.Lenses
    • examples/Code/FPinCSharp.ImmutableTypes

  • FP things to avoid in C#

    • Pattern Matching as a replacement for Polymorphism in C#
    • Currying
      • Currying is great if a language has first class support for it
      • Since in C# almost everything needs to be statically typed, you end up having very complex type signatures (Func<Func<...>>) which in my opinion, in many cases makes them less practical in C#
      • There will be times that we cannot avoid them (e.g Apply functions)
    • Recursion
      • How to write stack safe tail recursive functions using trampolining technique (fixing our not so stack safe Loop function in Examples 1-4)