问题描述
我理解时会怀疑，Dart语言中的编译时常数和运行时常数，我是dart语言的初学者，我在google中搜索到没有涉及此问题的文章，所以在此先感谢
I have Doubt when understand, Compile-time constant and runtime constant in Dart language, I am a beginner in dart language, I searched in google there is no article that covers this question, So thanks in advance
推荐答案
Dart中没有运行时常量"，而不是通常使用常量"一词的方式.所有常量都是编译时常量，这意味着它们的整个值可以在编译时确定，它们是高度不变的，并且如果两个常量，则编译器可以规范化对象表达式最终以状态完全相同的对象结束.
There are no "run-time constants" in Dart, not the way the word "constant" is generally used. All constants are compile-time constants, meaning that their entire value can be determined at compile-time, they are deeply immutable, and the compiler can canonicalize the objects if two constant expressions end up with objects that have the exact same state.
编译时常量"一词的名称来自规范，该规范讨论了编译时常量表达式".这些表达式的结果仅称为常量".
The name "compile-time constants" wording comes from the specification which talks about "compile-time constant expressions". The results of those expressions are just called "constants".
您可以说 final x = List< int> .unmodifiable([1]); 定义了一个常数.它肯定是一个不能修改的对象，但是在Dart术语中却不是传统上称为 constant 的对象-不能在语言需要恒定值的地方使用.
You can say that final x = List<int>.unmodifiable([1]); defines a constant. It's certainly an object which cannot be modified, but it's not what would traditionally be called a constant in Dart terminology - it cannot be used in the places where the language requires a constant value.
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