Helpers for pairlist and language nodes
Important: These functions are for expert R programmers only. You should only use them if you feel comfortable manipulating low level R data structures at the C level. We export them at the R level in order to make it easy to prototype C code. They don't perform any type checking and can crash R very easily (try to take the CAR of an integer vector — save any important objects beforehand!).
new_node(car, cdr = NULL) node_car(x) node_cdr(x) node_caar(x) node_cadr(x) node_cdar(x) node_cddr(x) node_poke_car(x, newcar) node_poke_cdr(x, newcdr) node_poke_caar(x, newcar) node_poke_cadr(x, newcar) node_poke_cdar(x, newcdr) node_poke_cddr(x, newcdr) node_tag(x) node_poke_tag(x, newtag)
car, newcar, cdr, newcdr |
The new CAR or CDR for the node. These can be any R objects. |
x |
A language or pairlist node. Note that these functions are barebones and do not perform any type checking. |
newtag |
The new tag for the node. This should be a symbol. |
Setters like node_poke_car() invisibly return x modified
in place. Getters return the requested node component.
duplicate() for creating copy-safe objects and
base::pairlist() for an easier way of creating a linked list of
nodes.
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