(require 'macro) is the appropriate call if you want R4RS
high-level macros but don't care about the low level implementation. If
an SLIB R4RS macro implementation is already loaded it will be used.
Otherwise, one of the R4RS macros implemetations is loaded.
The SLIB R4RS macro implementations support the following uniform interface:
Takes an R4RS expression, macro-expands it, and returns the result of the macro expansion.
Takes an R4RS expression, macro-expands it, evals the result of the macro expansion, and returns the result of the evaluation.
filename should be a string. If filename names an existing file, the
macro:loadprocedure reads Scheme source code expressions and definitions from the file and evaluates them sequentially. These source code expressions and definitions may contain macro definitions. The
macro:loadprocedure does not affect the values returned by