require-extension which is a portable
mechanism to load selected SRFI modules. This is implemented in the
Guile core, there's no module needed to get SRFI-55 itself.
Require each of the given clause features, throwing an error if any are unavailable.
A clause is of the form
arg...). The only identifier currently supported is
srfiand the arguments are SRFI numbers. For example to get SRFI-1 and SRFI-6,(require-extension (srfi 1 6))
require-extensioncan only be used at the top-level.
A Guile-specific program can simply
use-modulesto load SRFIs not already in the core,
require-extensionis for programs designed to be portable to other Scheme implementations.