> On Aug 1, 2016, at 3:01 PM, Anton Zhilin via swift-evolution > <swift-evolution@swift.org> wrote: > 2016-08-02 0:52 GMT+03:00 Xiaodi Wu <xiaodi...@gmail.com > <mailto:xiaodi...@gmail.com>>: > On Mon, Aug 1, 2016 at 4:41 PM, Anton Zhilin via swift-evolution > <swift-evolution@swift.org <mailto:swift-evolution@swift.org>> wrote: > Disclaimer: I have not (yet) prepared a proposal, or even something that > could be considered a draft, but I want to hear public opinion on the topic. > > SE-0077 (about precedence groups) has been successfully implemented for Swift > 3. (A thousand thanks to John McCall!) It suggests a model where we can > prohibit certain operators from standing next to each other. > > This was intended to be the second part of that proposal. We now have to > think if we should drop some precedence relationships between standard > operators. Here are examples of parentheses dropping that can be ambiguous to > reader: > > 1/3 as Double // should we prohibit this? > > Why should we? I would absolutely want that to work exactly as it does now > (0.333333...). > > Strange enough, I've just run it and yes, 0.333333... But casting precedence > is lower than multiplicative, so I thought it would parse as '(1/3) as > Double'. Is it a bug?
You're applying C-style thinking. Swift does not have implicit promotions. Coercing the result of 1/3 to Double forces the operands to be Doubles as well. John.
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