grappling hook using mouse aim

i try to make 3D side scrolling game in that i want to use grappling machanics means

1) mouse aim for the grabbing (limited not far way) 2) when the player grab platform then use the left & right for swing 3) when the user release the click then grabbing cancel

anybody know how to do that

any code, idea, suggestion

thanks in advance

This Unity game have grappling hooks that work well:

http://www.globalgamejam.org/2010/grapplegrapple

You can download the project folder from that page and see how they did it.

I go through the above live its very nice & also same that I want but the problem is I dont understand the C# any JavaScript code ?