369 lines
5.4 KiB
Markdown
369 lines
5.4 KiB
Markdown
# TSL 基础语法完整版
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> 本文档是 `$tsl-guide` 的子文档，聚焦基础语法。代码风格与命名规范请见 `docs/tsl/code_style.md` 与 `docs/tsl/naming.md`。
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## 目录
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- [语言元素与注释](#语言元素与注释)
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- [变量与常量](#变量与常量)
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- [数据类型与字面量](#数据类型与字面量)
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- [数组与表数组](#数组与表数组)
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- [运算符与表达式](#运算符与表达式)
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- [函数](#函数)
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- [控制流](#控制流)
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- [异常处理](#异常处理)
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- [调试与性能相关语句](#调试与性能相关语句)
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---
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## 语言元素与注释
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### 标识符与关键字
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- 关键字为保留字（完整列表见 `docs/tsl/syntax_book/01_language_basics.md`）
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- 标识符用于变量、函数、类、unit 等命名
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### 注释
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```tsl
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// 行注释
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{ 块注释 }
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/* 另一种块注释 */
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```
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### 编译选项（语法级）
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```tsl
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{$Explicit+} // 要求变量先声明再使用
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{$Explicit-} // 关闭显式声明
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{$VarByRef-} // 默认参数按值传递（可用 in/var/out 覆盖）
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```
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---
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## 变量与常量
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### 赋值
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```tsl
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a := 1;
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b := 2.5;
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s := "hello";
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```
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### 常量
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```tsl
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const kPi = 3.14159;
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const kMaxRetry = 3;
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```
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### 显式变量声明（配合 `{$Explicit+}`）
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```tsl
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{$Explicit+}
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var a, b; // 多变量声明
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var c := 10; // 声明并初始化
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var d: integer; // 类型可写可省（类型信息不做强校验）
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```
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---
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## 数据类型与字面量
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常见类型（参考 `01_language_basics.md`）：
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| 类型 | 说明 |
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|------|------|
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| Integer / Int64 | 整数 |
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| Real | 浮点数 |
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| Boolean | 布尔值（true/false） |
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| TDateTime | 日期时间 |
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| String | 字符串 |
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| Binary | 二进制 |
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| Array | 数组 |
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| Matrix / TMatrix | 矩阵 |
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| NIL | 空值 |
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示例：
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```tsl
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i := 42;
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r := 3.14;
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b := true;
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t := Date();
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s := 'hello';
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n := nil;
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```
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字符串支持单引号或双引号，索引访问从 0 开始：
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```tsl
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s := "ABC";
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ch := s[0];
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```
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---
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## 数组与表数组
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### 一维数组（0-based）
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```tsl
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arr := array(2, 3, 5, 7, 11);
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first := arr[0];
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```
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### 字符串下标（表数组）
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```tsl
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row := array("Code": "0001", "Price": 12.3);
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code := row["Code"];
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```
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### 多维数组
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```tsl
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matrix := array((1, 2, 3), (4, 5, 6));
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value := matrix[0][1];
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```
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---
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## 运算符与表达式
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### 常用运算符
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- 赋值：`:=`, `+=`, `-=`, `*=`, `/=`
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- 算术：`+ - * / div mod ^`
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- 关系：`= <> < > <= >= like in`
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- 逻辑：`and or not`
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- 三目：`cond ? a : b`
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示例：
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```tsl
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c := a + b;
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ok := (a = b) or (a > 0);
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x := (a > b) ? a : b;
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```
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矩阵/数组相关的 `.=`、`.<` 等算符在扩展语法中说明（见 `06_extended_syntax.md`）。
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完整运算符清单见 `01_language_basics.md`。
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---
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## 函数
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### 基本结构
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```tsl
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function HelloTsl();
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begin
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d := Date();
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return DateToStr(d);
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end;
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```
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### 参数分隔与类型注解
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类型注解仅用于说明与阅读，编译器不做类型检查。
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- 无类型注解时用逗号分隔参数
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- 带类型注解时用分号分隔参数
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- 返回值类型写在 `)` 之后
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```tsl
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function F1(a, b);
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function F2(a: string; b: array of real);
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function F3(): void;
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```
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### 形参与实参（in/const/var/out）
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```tsl
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function Calc(in a, var b, out c);
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begin
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b := b + a;
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c := b * 2;
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return c;
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end;
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```
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### 缺省参数（新一代语法）
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```tsl
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function Foo(a, b = a + 1);
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begin
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return b;
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end;
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```
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### 命名参数（新一代语法）
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```tsl
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function FuncA(a, b, c);
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begin
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return array(a, b, c);
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end;
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result := FuncA(1, c: 3); // b 默认为 nil
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```
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### 变参（`...`）与 Params
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```tsl
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function SumAll(...);
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begin
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total := 0;
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for i, v in Params do
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total := total + v;
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return total;
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end;
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```
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相关内置：`Params`, `ParamCount`, `RealParamCount`。
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### 返回与退出
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```tsl
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return value; // 返回
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exit; // 退出函数
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```
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### 外部函数声明（external）
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```tsl
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function GetTickCount(): integer; stdcall; external "kernel32.dll" name "GetTickCount" keepresident;
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```
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更多外部接口与调用方式见 `03_functions.md`。
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---
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## 控制流
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### if / else if
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```tsl
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if x > 0 then
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y := 1;
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else if x = 0 then
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y := 0;
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else
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y := -1;
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```
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### if 表达式（新一代语法）
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```tsl
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ret := if x > 0 then x * x else 0;
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```
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### case
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```tsl
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case age of
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0: WriteLn("Baby");
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1: WriteLn("Toddler");
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else
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WriteLn("Other");
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end;
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```
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### while / repeat
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```tsl
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while cond do
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DoSomething();
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repeat
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DoSomething();
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until cond;
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```
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### for（to / downto / step）
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```tsl
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for i := 1 to 10 do
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sum := sum + i;
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for i := 10 downto 1 step 2 do
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sum := sum + i;
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```
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### for ... in（数组遍历）
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```tsl
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data := array('a': 1, 'b': 5, 'c': 3);
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sum := 0;
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for k, v in data do
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sum := sum + v;
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```
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### break / continue / goto
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```tsl
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while cond do
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begin
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if stop then break;
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if skip then continue;
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// ...
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end;
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goto found;
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label found;
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WriteLn("jumped");
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```
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---
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## 异常处理
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### Try / Except
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```tsl
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try
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v := StrToInt(s);
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except
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v := 0;
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WriteLn(ExceptObject.ErrInfo);
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end;
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```
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### Try / Finally
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```tsl
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try
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DoWork();
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finally
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Cleanup();
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end;
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```
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### Raise
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```tsl
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if a < 0 then raise "A 不能小于 0";
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```
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异常信息可通过 `ExceptObject.ErrInfo/ErrLine/ErrNo` 获取。
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---
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## 调试与性能相关语句
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```tsl
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debugreturn 1;
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```
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```tsl
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t1 := mtic;
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// ...
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elapsed := mtoc(t1);
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```
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更多调试/性能语法见 `02_control_flow.md` 与 `07_debug_and_profiler.md`。
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