Swift表达过于复杂，无法在合理的时间内解决 [英] Swift expression was too complex to be solved in reasonable time

问题描述

在Xcode中编译项目时出现错误，它说：

I'm having an error when compiling a project in Xcode, it says:

表达太复杂，无法合理解决时间;考虑将表达式分成不同的子表达式

Expression was too complex to be solved in reasonable time; consider breaking up the expression into distinct sub-expressions

代码如下：

static func random(min: CGFloat, max: CGFloat) -> CGFloat {
    return CGFloat(Float(arc4random()/0xFFFFFFFF) * (max - min) + min)
}

推荐答案

为什么不通过将表达式分解为两个子表达式来降低编译器的复杂性？

Why not reduce the complexity for the compiler by breaking the expression down into two sub-expressions?

static func random(min: CGFloat, max: CGFloat) -> CGFloat {
    let rand = CGFloat(arc4random()/0xFFFFFFFF)
    return (rand * (max - min) + min)
}

您还可以使用 UINT32_MAX （或更多 Swifty UInt32。 max 或 .max ）代替 0xFFFFFFFF 来提高可读性。如果我还记得， 0xFFFFFFFF 是< stdint.h> <中定义的无符号32位整数最大值的十六进制值。 / code>标头。

You can also use UINT32_MAX (or the more "Swifty" UInt32.max or .max) in place of 0xFFFFFFFF to improve readability. If I recall, 0xFFFFFFFF is the hex value of the max value of an unsigned 32-bit Integer as defined in the <stdint.h> header.

#define UINT32_MAX 0xffffffff  /* 4294967295U */

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