Problem Consider the fraction, n/d, where n and d are positive integers. If n < d and HCF(n,d)=1, it is called a reduced proper fraction. If we list the set of reduced proper fractions for d <= 8 in ascending order of size, we get: 1/8, 1/7, 1/6, 1/5, 1/4, 2/7, 1/3, 3/8, 2/5, 3/7, …
Indexer If your have a type that represents a collection of values, adding a custom indexer gives you a natural way to index directly into the object using the .[ ] operator. Take this simple Calendar class for instance, which keeps a map (F# equivalent of a Dictionary<TKey, TValue>) of notes against DateTime values: By …
F# – Adding custom indexer and slicer to your type Read More »
Normally, with languages like C# or Java, there is quite a bit of overhead in creating a quick and dirty program to do small tasks like bulk renaming files in a director, etc. This is the spot that is filled by scripting languages like Python, Perl and Ruby, but did you know that you can …
I touched on the topic of memoization in the past in relation to doing aspect-oriented programming with PostSharp, however, with functional languages like F#, Haskell or Erlang there is no such frameworks (although PostSharp should still work with F# to some extent) to help you. That’s not to say that you can’t do AOP in …
AOP with F# – Memoization using higher-order functions Read More »
In F#, you have the choice of using a struct or a record as a lightweight container for data. The similarities between the two are striking – both are immutable by default, neither can be inherited, and they both offer structural equality semantics by default too! However, there’s a key difference between them, their performance …
In my previous post on discriminated unions, I presented discriminated unions as an alternative to standard .Net classes to represent hierarchical data structures. However, in terms of data structure, discriminated unions share much more similarities with enums than they do classes – both allow you to define a set of named constants and associate some …
By default, tuples, discriminated unions and records have what is known as structural equality – i.e. if two instances of these types have the same set of values then they are considered equal, just like value types – despite being reference types: Tuples Discriminated Unions Records To facilitate this form of equality, the F# compiler …
F# – Referential equality for tuples, discriminated unions and records Read More »
Pattern matching is everywhere in F#, you can use it in let bindings, in function parameters, in for loops, everywhere, and it is totally amazing. It is in my opinion one of the best features of F#, and in functional languages in general, heck, Erlang goes as far as not having an assignment operator and …
F# – Exception handling the pattern matching way! Read More »
Ayande posted a tax calculation challenge the other day here, and here’s my F# solution for the challenge: Enjoy!
When you consider the age old problem of representing different shapes (circle, triangle, square, rectangle, etc.) my OO fed developer brain naturally jumps to a class hierarchy along the line of: This is perfectly fine and legit, but it’s not the only way to approach things. Since I’ve been on a more varied diet of …
F# – Use Discriminated Unions instead of class hierarchies Read More »
By continuing to use the site, you agree to the use of cookies. more information
The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.