Racket is a popular variant of the Scheme programming language. Its features and benefits include:
With this release, we are making Racket CS available, a beta version of the Racket on Chez Scheme implementation. Racket CS is "beta" quality for the v7.4 release. It works well enough to be worth trying, but there are likely too many lingering problems for a project to switch to Racket CS for production use at this time. We encourage you to kick the tires of the new CS releases and to help push this project forward by reporting any problems that you find.
This is a backward-incompatible change, but the use of single-flonums appears to be rare. Since Racket CS does not support single-flonums, disabling single-flonums by default smooths the transition from regular Racket and Racket CS.
The `read-single-flonum` parameter can be set to #t to enable reading single-flonum literals, but a better strategy in most cases is to use `real->single-flonum` when `single-flonum-available?` reports #t or when `single-flonum?` reports #t for a value (which implies that single-flonums must be supported). Where single-flonums are supported, Racket's compiler will fold a call of `real->single-flonum` on a literal number to a constant single-flonum value.