The CLR comprehensively and thoroughly parses the-f# Foundation

F # is a new object-oriented functional programming language for the Microsoft. NET Framework, which has been integrated into this year's release of Microsoft Visual Studio 2010. F # Sets simple, concise syntax and high static typing. This language is capable of tasks ranging from lightweight exploratory programming in F # Interactive to large-scale component development using Visual Studio based on the. NET Framework.

F # is designed to run entirely on the CLR. As a language based on the. NET Framework, F # makes full use of the rich library resources on the. NET Framework platform to build. NET libraries or implement. NET interfaces. F # also leverages most of the CLR core features, including generics, garbage collection, tail-call directives, and basic common Language Infrastructure (CLI) type systems.

This article describes some of the core concepts of the F # language and its implementation on the CLR.

A brief overview of F #

First, let's take a quick look at some of the core features in the F # language. For more information about these features in the F # language and other concepts that you are interested in, refer to the documentation on the F # Developer Center for Fsharp.net.

The most basic function of F # is the Let keyword, which binds the value to the name. Let can be used to bind data and function values to achieve top-level binding and local binding:

let　data　=　12

let　f　x　=
　　 let　sum　=　x　+　1
　　 let　g　y　=　sum　+　y*y
　　 g　x

F # provides several core data types, as well as a syntax for using structured data, including lists, typed optional values, and tuples:

let　list1　=　["Bob";　"Jom"]

let　option1　=　Some("Bob")
let　option2　=　None

let　tuple1　=　(1,　"one",　'1')

You can match these structured data types with other types by using an F # pattern matching expression. Pattern matching is similar to using switch statements in programming languages such as C, but provides more ways to match and extract parts from matched expressions, somewhat similar to how regular expressions are used for pattern-matching strings:

let　person　=　Some　("Bob",　32)

match　person　with
|　Some(name,age)　->　printfn　"We　got　%s,　age　%d"　name　age
|　None　->　printfn　"Nope,　got　nobody"

F # fully leverages the. NET Framework libraries to perform many tasks, such as accessing data from a wide variety of data sources.. NET libraries are used in F # in the same way that they are used in other. NET languages:

let　http　url　=
　　 let　req　=　WebRequest.Create(new　Uri(url))
　　 let　resp　=　req.GetResponse()
　　 let　stream　=　resp.GetResponseStream()
　　 let　reader　=　new　StreamReader(stream)
　　 reader.ReadToEnd()

Like C # or Visual Basic, F # is also an object-oriented language that can define any. NET class or structure:

type　Point2D(x,y)　=
　　 member　this.X　=　x
　　 member　this.Y　=　y
　　 member　this.Magnitude　=
　　　　 x*x　+　y*y
　　 member　this.Translate(dx,　dy)　=
　　　　 new　Point2D(x　+　dx,　y　+　dy)

In addition, F # supports two special types: records and recognizable unions. Records provide a simple representation of data values with named fields, and an identifiable union is a type expression that contains a number of different values, and the associated data in each value varies:

type　Person　=
　　 {　Name　:　string;
　　　 HomeTown　:　string;
　　　 BirthDate　:　System.DateTime　}

type　Tree　=
　　 |　Branch　of　Tree　*　Tree
　　 |　Leaf　of　int