TWC9: C9 goes global, Fast App Switching, Geo AR Toolkit, MEF 2.0

The C# code uses readonly to produce the immutability provided by F# by default. This is why they use full properties. However one can argue that C# does not depend on immutability as much as F# does so you won't write it like this anyway.

Silverlight Toolkit for Silverlight 5 is really cool, it has the same content pipeline support as XNA, with VS support, so SLXNA is a full 3D solution now, merging completed.

That Geo AR Toolkit looks really useful.

What's that car project mentioned a few times on the show?  Is that in another blog post or video online somewhere? 

re: F# eye for the C# guy slide deck

The slides were presented at DDD Belfast early in October. The inspiration for the title came from a talk by Leon Bambrick. The slide that got the focus in the Channel 9 video above was titled Light Syntax and was part of the Demos section, added as a reference for attendees.

The demo was primarily intended to help C# developers understand how F# maps to C#.

That said the comparison of number of lines of code is interesting. As discussed in the Channel 9 video above if we don't need the class to be immutable then C# Auto-Implemented Properties could be employed, however you'd still probably want a constructor and comments in your C# code, i.e.:

public class Person
{
    public Person(string name, int age)
    {
        Name = name;
        Age = age;
    }

    /// <summary>
    /// Full name
    /// </summary>
    public string Name { get; private set; }
    
    /// <summary>
    /// Age in years
    /// </summary>
    public int Age { get; private set; }
}

F# class types let you define a primary constructor in the parameter list that follows the type name, and by default F# triple-slash comments define summary blocks without the need for XML tags

type Person (name:string, age:int) =
    
    /// Full name
    member person.Name = name

    /// Age in years
    member person.Age = age

If we forgo the comments, this can be brought down to 1 line with an F# record:

type Person = { Name:string; Age:int }

The F# record above will automatically generate a constructor and properties for use from other .Net languages including C#; it is also immutable.

Further reading:

A look at F# from C#'s corner: http://www.servicestack.net/mythz_blog/?p=765

From C# to F#: a developer's perspective: http://www.developerfusion.com/article/122233/from-f-to-c-a-developers-perspective/

C# Light Syntax: http://trelford.com/blog/post/LighterCSharp.aspx

More discussion on Reddit: http://www.reddit.com/r/programming/comments/l294s/f_for_c_developers/

What model laptop are they using?