powered by
is.language
TRUE
x
name
call
expression
is.language(x)
ll <- list(a = expression(x^2 - 2*x + 1), b = as.name("Jim"), c = as.expression(exp(1)), d = call("sin", pi)) sapply(ll, typeof) sapply(ll, mode) stopifnot(sapply(ll, is.language))
Run the code above in your browser using DataLab