Parsing a string C# LINQ expression

I'm trying to do some really dynamic querying here - preferably without invoking the compiler at runtime though.

I have a string containing a LINQ expression, e.g.

var s = "from a in queryable where a.Type == 1 select a";

How can I get the resulting IQueryable or Expressions from that?

I've seen LINQPad and RavenDb both do this so I'm convinced there's a way, I just haven't found it yet.