如何将符号作为Scheme中的函数应用？

Is there a way I can apply '+ to '( 1 2 3)?

有没有办法可以申请'+ to'(1 2 3)?

edit: what i am trying to say is that the function i get will be a symbol. Is there a way to apply that?

编辑:我想说的是我得到的功能将是一个符号。有办法申请吗?

Thanks.

6 个解决方案

#1

(apply (eval '+) '(1 2 3))

Should do it.

应该这样做。

#2

In R5RS you need

在R5RS中你需要

(apply (eval '+ (scheme-report-environment 5)) '(1 2 3))

The "Pretty Big" language in Dr. Scheme allows for:

Dr. Scheme中的“Pretty Big”语言允许:

(apply (eval '+) '(1 2 3))

#3

How about 'apply'? Use the variable + instead of the symbol + .

“申请”怎么样?使用变量+而不是符号+。

(apply + '(1 2 3))

R5RS

#4


;; This works the same as funcall in Common Lisp:
(define (funcall fun . args)
  (apply fun args))

(funcall + 1 2 3 4) => 10
(funcall (lambda (a b) (+ a b) 2 3) => 5
(funcall newline) => *prints newline*
(apply newline) => *ERROR*
(apply newline '()) => *prints newline*

Btw, what's the deal with this "syntax highlighting" ??

顺便问一下,这个“语法高亮”的处理方法是什么?

#5

In Racket's scheme it would be

在Racket的计划中它会是

#lang scheme

(define ns (make-base-namespace))
(apply (eval '+ ns) '(1 2 3))

#6

How about the scheme "apply"

该计划“适用”怎么样

(apply + `(1 2 3)) => 6

I hope that was what you were asking :)

我希望那就是你所要求的:)

#1

(apply (eval '+) '(1 2 3))