Swift expression was too complex to be solved in reasonable time

Question

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

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

here's the code:

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

Whitt

Answer 1

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)
}

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 */

Undergird

I think this misses the point (or at least the question I wanted answered!): what does that compiler error mean??? – Bribery

What do you think it means? The expression was too complex for the compiler, and it timed out trying to resolve the + and * operator overloads: devforums.apple.com/message/1097960#1097960 – Undergird

Ah! Overload resolution. Got it. – Bribery

UInt32.max is a bit more Swift-y: let rand = CGFloat(arc4random() / .max) – Jay

@Jay great point! Edited my answer to also include this style option. – Undergird