Original
Declared constants
Several different language
constructions are referred to as constants. There are numeric constants (also
called numerals) like 17, and string constants (also called character
strings or string literals) like 'Hello world!'. Every enumerated
type defines constants that represent the values of that type. There are
predefined constants like True, False, and nil. Finally,
there are constants that, like variables, are created individually by
declaration.
Declared constants are either true constants or typed constants. These two kinds of constant are superficially similar, but they are governed by different rules and used for different purposes.
See also
译文
声明常量
常量可以归结为几种不同的语言造句。有数字常量（也叫数字），如17，串常量（也叫字符串或串文本），如 'Hello
world!' 。每个列举的类型定义了一个表示该类型值的常量。Object
Pascal提供了预定义常量，如True、False和nil等。此外，还有一些常量，和变量一样，通过声明单独创建。
声明的常量可以是真实常量，也可以是类型常量。这两种常量表面相似，但它们具有不同的管理规则和不同的使用目的。