18 Data Representation in Guile

by Jim Blandy

In order to make sense of Guile's SCM_ functions, or read libguile's source code, it's essential to have a good grasp of how Guile actually represents Scheme values. Otherwise, a lot of the code, and the conventions it follows, won't make very much sense. This chapter is meant to provide the background necessary to read and write C code that manipulates Scheme values in a way that is compatible with libguile.

We assume you know both C and Scheme, but we do not assume you are familiar with Guile's implementation.

• Data Representation in Scheme: Why things aren't just totally straightforward, in general terms.
• How Guile does it: How to write C code that manipulates Guile values, with an explanation of Guile's garbage collector.
• Defining New Types (Smobs): How to extend Guile with your own application-specific datatypes.