TYPEOF: The type of an R object

In ramiromagno/c3po: From C to R and back again

Description

\Sexpr[results=rd, stage=render]{c3po:::badge('mfn')}

TYPEOF is a function-like macro that determines the type of an SEXPREC object.

Arguments

x	an SEXP pointer.

Value

A SEXPTYPE value.

Declaration

#define TYPEOF(x) ((x)->sxpinfo.type)

In Rinternals.h.

See Also

typeof

Examples

# Determine R objects' SEXPTYPEs
sexptype <- inline::cfunction(c(x = "ANY"),
 ' SEXP type_value;
   type_value = PROTECT(Rf_ScalarInteger(TYPEOF(x)));
   UNPROTECT(1);
   return type_value;
 ')

# NULL, returns 0
sexptype(NULL)
# an empty pairlist also returns 0
sexptype(pairlist())

# symbol, returns 1
sexptype(as.symbol('a'))

# dotted pair list, returns 2
sexptype(pairlist(a = 1))

# closure, returns 3
sexptype(function(x) {x + 1})

# environment, returns 4
sexptype(.GlobalEnv)

# promises, returns 5
# But how to get one?

# language (call and formulae), returns 6
sexptype(call("sin", pi))
sexptype(~ x + 2)

# special forms, returns 7
sexptype(.Internal)

# builtin non-special forms, returns 8
sexptype(.Primitive("sqrt"))

# "scalar" string type (internal only), would return 9
# No way of getting hold of one of this in R land

# logical vectors, returns 10
sexptype(TRUE)
sexptype(FALSE)
sexptype(NA)

# codes 12 and 13 are no longer in use
# used to be for factors and ordered factors in the 1990s

# integer vectors, returns 13
sexptype(1L)
sexptype(factor('as')) # still an integer vector

# real vectors, returns 14
sexptype(1)
sexptype(pi)
sexptype(double(1))
sexptype(numeric(1))

# complex vectors, returns 15
sexptype(1i)
sexptype(0i)
sexptype(0 + 1i)
sexptype(NA_complex_)

# string vectors , returns 16
sexptype("alice in wonderland")

# TODO: dot-dot-dot object, returns 17

# TODO: "any" args, returns 18

# generic vectors, i.e., lists, returns 19
sexptype(list())

# expression, returns 20
sexptype(expression(x + 2))

# TODO: byte code, returns 21

# TODO: external pointer, returns 22

# TODO: weak reference, returns 23

# raw bytes, returns 24
sexptype(raw(2))

# TODO: S4, non-vector, returns 25

# TODO: fresh node created in new page, returns 30

# TODO: node released by GC, returns 31

# TODO: Closure or Builtin or Special, returns 99

ramiromagno/c3po documentation built on Jan. 5, 2021, 8:01 p.m.