Node:Immediates vs Non-immediates, Next:Immediate Datatypes, Previous:Conservative GC, Up:How Guile does it
Guile classifies Scheme objects into two kinds: those that fit entirely
SCM, and those that require heap storage.
The former class are called immediates. The class of immediates includes small integers, characters, boolean values, the empty list, the mysterious end-of-file object, and some others.
The remaining types are called, not surprisingly, non-immediates. They include pairs, procedures, strings, vectors, and all other data types in Guile.
|int SCM_IMP (SCM x)||Macro|
|Return non-zero iff x is an immediate object.|
|int SCM_NIMP (SCM x)||Macro|
Return non-zero iff x is a non-immediate object. This is the
exact complement of |
Note that for versions of Guile prior to 1.4 it was necessary to use the
SCM_NIMP macro before calling a finer-grained predicate to
determine x's type, such as
SCM_VECTORP. This is no longer required: the definitions of all
Guile type predicates now include a call to