Original
Type identity
Type identity is almost
straightforward. When one type identifier is declared using another type
identifier, without qualification, they denote the same type. Thus, given the
declarations
type
T1 = Integer;
T2 = T1;
T3 = Integer;
T4 = T2;
T1, T2, T3, T4, and Integer all
denote the same type. To create distinct types, repeat the word type in
the declaration. For example,
type
TMyInteger = type Integer;
creates a new type called TMyInteger
which is not identical to Integer.
Language constructions that
function as type names denote a different type each time they occur. Thus the
declarations
type
TS1 = set of Char;
TS2 = set of Char;
create two distinct types, TS1 and TS2.
Similarly, the variable declarations
var
S1: string[10];
S2: string[10];
create two variables of distinct types. To
create variables of the same type, use
var S1,
S2: string[10];
or
type
MyString = string[10];
var
S1: MyString;
S2: MyString;
See also
Type compatibility and identity: Overview
译文
类型等同
类型兼容性几乎是简洁明了的。当定义一个类型标识符时使用了另一个类型标识符，并且没有限定词，那么它们表示相同的类型。例如，对于给出的声明
type
T1 = Integer;
T2 = T1;
T3 = Integer;
T4 = T2;
这里的T1、T2、T3、T4和Integer都表示相同的的类型。要创建不同的类型，可以在声明中重复使用保留字type。例如
type
TMyInteger = type Integer;
这里创建了叫做TMyInteger的新的类型，它与Integer是不等同的。
对于产生类型名称的语言造句，每次出现都表示不同的类型。对于如下声明
type
TS1 = set of Char;
TS2 = set of Char;
这里创建了两个不同的类型，TS1和TS2。同样，对于变量声明
var
S1: string[10];
S2: string[10];
这里创建了两个类型不同的变量。要创建相同类型的变量，应使用声明
var S1,
S2: string[10];
或声明
type
MyString = string[10];
var
S1: MyString;
S2: MyString;