Program images and portable Scheme backends for Jolt

Two features landed in Jolt recently, both of which fell out from loosening the coupling between Jolt and the host runtime. The first is the ability to serialize program images in the style of Common Lisp and Smalltalk, and the second is to have a portable Scheme layer decoupled from the Chez runtime. Let's take a look at what these things buy Jolt in practical terms.Images: a black box for your programIf you've ever had to support a production system like a web application, then you know the value of having good logging. What typically happens is that you sprinkle statements through the code, ship them somewhere searchable, and then use them as bread crumbs when something breaks. When a system has errors, you have to first reconstruct what it was doing to understand what happened. If your logging didn't capture a critical piece of information, then the investigation devolves into guess work and attempts to reconstruct the state which caused the error. This can be a particularly…