Questions tagged [f#]
F# is a succinct, expressive, and efficient functional and object-oriented language for .NET
352
questions
3
votes
1answer
189 views
Trying to do Type-Driven Development in F#
I've been wanting to try out F# for some real world programming so I decided to try rewriting a program that is being used at work.
It can be reduced to a few steps:
Get report templates.
In this ...
2
votes
1answer
197 views
Summations and products in F#
I was bored, and looking to do something that involved anonymous functions, and it was suggested by @Quill, that I create a summation function. I decided to also include a product function as well to ...
3
votes
1answer
74 views
Renaming video files based on episode title lookup
I'm new to F#, so I've ported an old Python script I have to F#. It scans a directory for files named something like Game.Of.Thrones.S01E02.xvidblahblah.mp4 or <...
1
vote
1answer
58 views
Creating a structured category list in F#
This takes a list of categories and organizes them into a tree-type structure based on their parentId. This code works, but is obviously a little over-complicated. ...
1
vote
1answer
141 views
5
votes
1answer
149 views
Lindenmayer System String Generator in F#
Lindenmayer Systems or L-systems are fractals that can be constructed by applying replacement rules to a string for a certain amount of iterations. For example:
...
10
votes
1answer
877 views
Small game written in F#
I'm trying to wrap my head around F#. I'd like your honest opinion about this simple game source code that I wrote. Rules are simple:
Every player has soldiers and territory
Player can recruit ...
4
votes
1answer
143 views
Utopian Tree in F#
This is the Utopian Tree in F# (from HackerRank)
The Utopian tree goes through 2 cycles of growth every year. The first
growth cycle of the tree occurs during the monsoon, when it doubles in
...
6
votes
1answer
118 views
Hello Functional World: Counting occurrences of each letter
Coming from a OO (C#) background, I am trying to learn some FP. To help me transition, I am trying to learn F#. I am taking baby steps.
I set myself a simple challenge to count the instances of each ...
5
votes
2answers
709 views
Add two numbers stored as a list in F#
I am solving the following problem:
You are given two lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two ...
6
votes
1answer
858 views
Game of life in F#
First attempt at doing anything F#-y from a very heavy C# background, think I've grasped the fundamentals of FP, but always good to get other eyes on it:
...
8
votes
2answers
1k views
Mock/Stub out filesystem in F# for unit testing
I'm looking to do some basic verification testing on my functions that write to the filesystem.
I took a hint from here on how to mock out the filesystem using an interface, but I'm kinda bummed on ...
4
votes
2answers
492 views
Reverse Polish Notation in F#
In my question to learn F#, I've decided to get one step closer to creating a programming language, and implement this simple Reverse Polish Notation "interpreter" of sorts.
It does not allow for ...
7
votes
1answer
510 views
Efficient generic type conversion between numeric types in F#
It's easy to write a function that adds two ints in F#:
let add x y = x + y
Actually, it's the same as:
...
10
votes
2answers
220 views
F# inventory system - Part 2
I've refactored my previous inventory system, and added a few features like removing items from the Inventory class, easily obtaining the current selected item ...
7
votes
1answer
553 views
F# inventory system
To learn F#, I've implemented this very simple inventory system. While I'm proud that that it's my first program, and that it works, there are still a few areas that I'd like tips on, namely these:
I ...
10
votes
2answers
9k views
Reading input from console in F# (as a sequence of lines)
Consuming input line-by-line until the end is often useful. In C# I would write the following loop:
while ((line = Console.ReadLine()) != null) {
// ...
I ...
2
votes
1answer
595 views
Building and flattening a dependency graph
The Problem
Given a list of dependencies ('a * 'a) list where the first item has a dependency on the second item, construct a dependency graph and then 'flatten' ...
3
votes
1answer
62 views
Projecting future positions
My code takes a starting position (which must be completed) and a list of updates (each element of which is optional). It then projects future positions, using the appropriate value from each update, ...
5
votes
1answer
425 views
Sudoku game logic
I am trying to create a Sudoku game in F# and I'm having a bit of trouble with the file reading and writing. But since I've also just started programming in f# I would like to check if my thinking is ...
0
votes
2answers
401 views
Extracting meta data from nupkg file with F# looks like C# Linq
The code snippet below examines a nuget package file (zip file with meta) and extracts all file names referenced inside. The final result should be a ...
1
vote
1answer
789 views
Saving an uploaded file and returning form data
I am new to F#. This code is basically a port I did from C#. I am sure there is room for a ton of improvement, so how can I improve and make this more efficient?
...
4
votes
0answers
247 views
Aggregation of values over a hierarchy
I have a number of objects of a type Workplace that exist in a hierarchy that is given by some properties (Department, ...
6
votes
1answer
198 views
Test file word cloud in F#
This code is meant to take in a command line argument and output a 'tag cloud'. It's more of an exercise in learning F# for me because this is my first non-tutorial code file. How could this code be ...
7
votes
1answer
205 views
Small console app to execute some remote scripts
I'm learning F# and functional programming, from a background in C# and imperative/OOP. I've ported a small, one-off console app from C# to F#. The port worked (the app behaves the same way), but I'd ...
9
votes
1answer
298 views
Brainfuck interpreter in F#
I have some concerns, like the updateValue function. I was trying to follow the functional paradigm, but I wonder if I could use another approach or something.
My ...
1
vote
2answers
64 views
Better yielding tuple-d union case values in list generation
I have a situation where I'm stitching three different unions into a triplet tuple for building a map/dictionary of strongly typed values keyed on a string.
One of the union cases is very large, the ...
4
votes
1answer
384 views
Command Dispatcher for messaging using MailboxProcessor
This code is intended to process commands in a CQRS+Messaging system. It will parallelize the message processing to the degree you specify by the msgToIdFn ...
3
votes
1answer
98 views
Finding a customer's gender
I have been playing with Async/parallel execution in entity framework for while. I'm not sure if I'm doing it right.
I have two entity contexts: one for reading and one for writing. The reading ...
2
votes
1answer
69 views
Extracting a maximum from zipped lists
I have code that zips 3 lists, finds a maximum and extracts part of the max tuple. Isn't there a shorter way to do this in F#?
...
1
vote
0answers
137 views
Boiler-plate reduction or elimination layer for System.Data .net 4.0
I'd really like to get this to be as clean as possible such that the C# access to it looks succinct. To that end, I've made C# helper methods that abstract out things like ...
8
votes
1answer
1k views
Generic build script using Fake
I have something like a generic build script for a group of projects. I am using Fake but my F# skills are pretty bad. Would you please take a look and point where I can improve it?
ORIGINAL
...
4
votes
1answer
932 views
CRUD (database layer) for F# with TypeProviders
I am a newbie in F# and I am thinking about use F# in my next project. The project will work the database and I need to store and retrieve instances of objects in the Db.
Could you please check my ...
2
votes
1answer
55 views
Structuring Test Data
I'm just getting started with F# and was writing some unit tests for some functionality I had written. In the interest of brevity, I decided to create some lists of the different test cases and just ...
5
votes
1answer
537 views
Lightweight TicTacToe in F#
This is more of a 'model' of TicTacToe, as you'll see it's not "gameified" in the sense that it will allow for inputs and outputs nor will it record any "active" state of the game but those things are ...
3
votes
2answers
1k views
Select some indexes in a list of lists
I have a record type which holds a list of table rows. Each row is also a list. The first row is assumed to be the header row. In addition the type optionally defines a filter - a list of columns (the ...
1
vote
2answers
225 views
3
votes
0answers
152 views
DSL design for iOS Autolayout
I am building a small DSL for iOS' autolayout feature. Obviously I want to have a typesafe way to define autolayouts instead of doing VSL. I came up with the following:
...
3
votes
1answer
197 views
Decompose a value as a sum of square numbers
My daughter had a question on her maths homework which was to write a value as a sum of 4 or fewer square numbers.
For example, x = 73 could be 36 + 36 + 1.
I came up with a really brute force ...
2
votes
1answer
424 views
Ordering a sequence of objects by type
The below code takes an incoming sequence of objects, checks each object's type and then yields the object in a specific order. This is all taking place in an active pattern. As I am still new to F#,...
2
votes
0answers
171 views
AES256 + HMACSHA256 'secretbox'
I aim to create a few primitives for creating AES256-then-HMACSHA256 secured session state through cookies.
What I've considered:
HMAC instead of plain sha to avoid hash extension attacks
input ...
4
votes
1answer
764 views
Add spaces before uppercase letters
I'm trying to convert some very simple C# string utility functions to F# as a learning exercise. Ignore the fact that the C# version is implemented as an extension method for the moment.
The ...
15
votes
0answers
171 views
Encoding the problem domain of products and prices into the typesystem in F#
I'm trying to design a model for purchasing amounts of products in F#, following the ideas for designing for correctness (source). The idea is to use the type system to capture the different legal ...
5
votes
2answers
322 views
Project Euler 3: Getting the largest prime factor of a number
I'm looking for some general feedback on my solution to Project Euler challenge 3
The prime factors of 13195 are 5, 7, 13 and 29. What is the largest
prime factor of the number 600851475143 ?
<...
3
votes
2answers
171 views
Project Euler #2 in F#
Project Euler Problem 2 asks for the sum of all even Fibonacci numbers below 4 million.
My first attempt at this problem using functional programming with F#. I would've liked to use some kind of ...
4
votes
2answers
546 views
Project Euler Problem 1 - Functional approach?
I'm trying to learn F# right now coming from C# and I'm finding it a great difficulty to "reconfigure" my mind to the functional programming mindset. So I'm going to attempt a few Project Euler ...
10
votes
2answers
233 views
Is this Bridges code F# idiomatic?
Introduction
I'm primarily a C# programmer, just starting out with learning F#. I found myself with a problem which felt like it was appropriate for a functional language, and now that I have the ...
2
votes
1answer
200 views
Simple actor system in F#
Any thoughts on my actor model here? Obviously it doesn't have implementation for concurrency as it stands- being completely synchronous, but it should be easy to make the send/become/create be sent ...
3
votes
2answers
772 views
Longest Common Subsequence and Longest Subsequence Palindrome
The following code computes:
The longest common subsequence between two strings, where a subsequence of a sequence does not have to consist of contiguous elements of the sequence.
The longest ...
5
votes
1answer
325 views
The Functional FizzBuzz Kata
I run a coding dojo at work. For one session I'm to showing that you can use a kata to get into a new language.
I'm using the FizzBuzz Kata to to show F# (and JavaScript) because it is short. The ...
