Using pipes with higher-order functions

pipe-function.r

# Higher order function that returns a function:

make_sum = function () {
    # Some code here …
    message('Requesting to calculate a sum')
    sum
}

seq(1, 10) %>% sum
# Now, logically, what does this do?
seq(1, 10) %>% make_sum()
# Correct:
seq(1, 10) %>% make_sum()()

seq(1, 10) %>% (make_sum())

the pipe will evaluate rhs first, if it is parenthesized.. Can also be used if RHS e.g. generates a call.

Sure, I’m not saying that there’s no solution; all I’m saying that not using parentheses is inconsistent, because if foo %>% bar executes bar(foo), then I expect foo %>% bar() to execute bar()(foo). It’s a stumbling block in the API, nothing more, nothing less.