R/function_type.R

In tribe: Play with the Tribe of Attributes

# Determine whether an expression counts as a function in a magrittr chain.
#
# @param a non-evaluated expression.
# @return logical - TRUE if expr represents a function, FALSE otherwise.
# @author Stefan Milton Bache and Hadley Wickham
is_function <- function(expr) {
  is.symbol(expr) || is.function(expr)
}

# Prepare a magrittr rhs of funtion type
#
# @param a an expression which passes \code{is_function}
# @return an expression prepared for functional sequence construction.
# @author Stefan Milton Bache and Hadley Wickham
prepare_function <- function(f) {
  as.call(list(f, quote(.)))
}