is_pairlist()
checks that x
has type pairlist
.
is_node()
checks that x
has type pairlist
or language
.
It tests whether x
is a node that has a CAR and a CDR,
including callable nodes (language objects).
is_node_list()
checks that x
has type pairlist
or NULL
.
NULL
is the empty node list.
is_pairlist(x) is_node(x) is_node_list(x)
x | Object to test. |
---|
These functions are experimental. We are still figuring out a good naming convention to refer to the different lisp-like lists in R.
is_call()
tests for language nodes.