[racket] how to get exact results from get-text-extent

On Fri, Dec 19, 2014 at 02:05:30PM -0800, Matthew Butterick wrote:
> 
> What's the best way to impose systematic number typing on existing untyped
> code, for instance, forcing everything to be a flonum? Does it require
> switching to Typed Racket? Or does mean making explicit calls to
> `exact->inexact` and using the flonum math operators? Or some other
> technique?

As I understand it, Typed Racket has exactly the same semantics for 
valid programs as regular Racket.  It won't force anything to be a 
flonum, but it will complain if you got it wrong when your code doesn't 
match your declared types.

But it may run faster, because thingss it checks before run time do 
not need to be checked again at run time.

-- hendrik