Scala方式写lisp-like预测？

Question

Scala中是否有像lisp这样的语言结构progn？
谢谢!

Answer 1

是的,花括号.

progn evaluates forms, in the order in which they are given.

The values of each form but the last are discarded.

Examples:

 (progn) =>  NIL
 (progn 1 2 3) =>  3
 (progn (values 1 2 3)) =>  1, 2, 3
 (setq a 1) =>  1
 (if a
      (progn (setq a nil) 'here)
      (progn (setq a t) 'there)) =>  HERE
 a =>  NIL

现在一样,但在scala中:

scala> {}

// Unit is not written explicitly, but it is here
scala> {1; 2; 3}
// warnings omitted
// res1: Int = 3

scala> {(1, 2, 3)}
// res2: (Int, Int, Int) = (1,2,3)

// no direct analog for setq, skipping other examples

并确保您按照给定的顺序评估表单:

scala> {println('1'); println('2'); println('3')}
1
2
3