Question

令人感到担心的是,这种情况非常复杂。

我想谈谈一个论点,但也知道应当对其加以评价的环境。与此类似:

make.promise = function(x = print(b), b = 7) {
    expr = substitute(x)
    env  = parent.frame()

    function() {
        eval(expr, env)
    }
}

p1 = (
    function() {
        a = 2
        make.promise(print(a))
    }
)()

p2 = make.promise()

The problem is, if no argument is supplied for x, its environment becomes the local environment of make.promise(), and I don t know how to detect that. Is there a function other than substitute I could use that also captures the environment?

Answer 1

<代码>make.promise的简单实施将:

make.promise <- function(x) {
    function() x
}

但是,我不认为你重新寻找的东西。我不知道找到相关环境的任何途径——你可以尝试通过电子邮件传送邮件清单。

友情链接