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Using callCC with higher order functions in R

I am trying to figure out how to get a call call function for a function short circuit function to work with functions like lapply and Reduce.

Motivation

This would lead to a decrease and, accordingly, asymptotic efficiency> O (n), allowing you to exit the calculation earlier.

For example, if I search for a value in a list, I could display the “finder” function in the list, and the second one that is found will stop working, and that value will be returned (similar to breaking a loop, or using the return statement to break out earlier).

The problem is that I am having trouble writing the functions that apply, and the reduction should be done using the style that callCC requires.

Example

Let's say I'm trying to write a function to find the value "100" in a list: something equivalent

imperativeVersion <- function (xs) {
    for (val in xs) if (val == 100) return (val)
}

The transition function to lapply will look like this:

find100 <- function (val) { if (val == 100) SHORT_CIRCUIT(val)  }
functionalVersion <- function (xs) lapply(xs, find100)

This is (obviously) a failure since the short circuit function has not yet been defined.

callCC( function (SHORT_CIRCUIT) lapply(1:1000, find100) )

The problem is that it also crashes because the short circuiting function was not around when find100 was found. I would like something like this to work.

the following action is performed because SHORT_CIRCUIT IS is defined when the function passed to lapply is created.

callCC(
    function (SHORT_CIRCUIT) {
        lapply(1:1000, function (val) {
             if (val == 100) SHORT_CIRCUIT(val)
        })
)

How can I define SHORT_CIRCUIT in a function passed to lapply without defining it as a string?

I know that this example can be achieved using loops, reduction, or any other number of ways. I am looking for a solution to the problem of using callCC with lapply and shortening in concrete.

- , , . , - :)

: " "; .

+4
2

:

find100 <- function (val) {
    if (val == 100) SHORT_CIRCUIT(val)
}

short_map <- function (fn, coll) {


    callCC(function (SHORT_CIRCUIT) {

        clone_env <- new.env(parent = environment(fn))
        clone_env$SHORT_CIRCUIT <- SHORT_CIRCUIT

        environment(fn) <- clone_env
        lapply(coll, fn)

    })
}

short_map(find100, c(1,2,100,3))

callCC , , . , .

+1

, , :

    find100 <- "function (val) { if (val == 100) SHORT_CIRCUIT(val)  }"
    callCC( function (SHORT_CIRCUIT) lapply(1:1000, eval(parse(text = find100))) )
    #[1] 100
0

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