造成这种速度优势的原因是数组是固定大小的，而默认的 PHP 数组是可变大小的，并且不允许非数值型索引。

This speedup is due to the fact that the array is a fixed size, not a variable-sized one like the default PHP one is, and that non-numeric indexes are not allowed.

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本地变量空间用作该函数的通用存储空间，寄存器保存区用于保存函数所使用的非可变寄存器的值。

The local variable space is used as a general storage area for the function, and the register save area is used to save the values of non-volatile registers that the function USES.

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Anders Janmyr出色地概述了新功能，包括支持非扩展性和不可变对象的能力。

Anders Janmyr has a good overview of the new features including the ability to support non-extensible and immutable objects.

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