csh
40a9885eb4
- flag weak candidates (no intent/heading/identifier/tag hit) and exit 2 when every candidate is weak: mis-hits used to be indistinguishable from real hits, so the retry-with-better-terms loop never fired - accept multiple ids per --section for batch fetch, failing atomically on any unknown id so a partial fetch cannot pass as complete - move query synonyms and page intent aliases to data/lexicon.json and enforce alias/page correspondence in --check; curation data no longer lives in the engine - document the weak-hit rule, batch fetch and prelude-once guidance in SKILL.md, with curation discipline in data/README.md - drop 11_pitfalls.md, renumber the trailing pages and spread retrieval tags across topics; lexicon keys are page filenames, so the renumbering and the new --check rule cannot land in separate commits
485 lines
8.4 KiB
Markdown
485 lines
8.4 KiB
Markdown
# TSL 控制流
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这一篇只收录流程控制与异常控制，不讨论金融语义。
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## 本篇职责
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回答“`if`、`case`、`for`、`while`、`repeat`、`break`、`continue`、`try`、`raise` 这些流程结构在 TSL 里到底怎么写，哪些写法可以直接生成”。
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## 核心规则
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- `if ... then ... else ...` 默认写成块式分支：`then begin ... end else begin ... end`。
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- 块式分支内部的普通语句必须用分号结尾。
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- 控制流块的 `begin ... end` 后可以加分号也可以不加（语法都允许）。
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- `for` 支持 `to`、`downto`、可选 `step`，以及 `for i, v in array` 遍历。
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- `while` 和 `repeat ... until` 都可直接使用；`repeat` 至少会先执行一轮再判断结束条件。
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- `break` 会跳出当前最近一层循环，`continue` 会跳过当前轮剩余语句。
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- `case ... of ... else ... end` 可作为语句形态生成；`end` 后可以加分号也可以不加。
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- `value := case ... of ... else ... end;` 可作为表达式形态生成；表达式形态赋值语句本身要用分号结尾。
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- `case` 分支标签支持逗号并列和 `to` 区间。
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- `try ... except ... end` 可以捕获 `raise` 产生的错误，并继续执行后续语句。
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- `exceptObject.errInfo` 在 `except` 块中可读，能拿到当前错误信息。
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- `exceptObject.errLine` 和 `exceptObject.errNo` 在 `except` 块中也可读。
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- `try ... finally ... end` 无论是否报错，都会先执行 `finally`；如果没有 `except` 吞掉错误，脚本仍会在 `finally` 之后报错终止。
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- `raise "message"` 是最小抛错写法。
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- `goto`、`debugReturn`、`debugRunEnv`、计时和性能分析器这类“控制流补充工具”统一放到 [14_debug_and_profiler.md](14_debug_and_profiler.md)。
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## 可直接照写示例
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使用这些示例时遵守：
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- 条件表达式、比较、布尔值和普通赋值的事实见 [06_expressions_and_operators.md](06_expressions_and_operators.md)。
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- 函数里的控制流只按控制流语法处理；函数文件模型、返回值和参数规则见 [05_functions_and_calls.md](05_functions_and_calls.md)。
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- `goto`、`debugReturn`、计时和性能分析器不在本页生成，相关事实见 [14_debug_and_profiler.md](14_debug_and_profiler.md)。
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### `if`、`while`、`repeat ... until`
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<!-- tags: 条件判断, 循环, 判断语句, 直到满足, 反复执行 -->
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代码块身份：可直接照写示例
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```tsl
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flag := 1;
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if flag > 0 then
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begin
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value := 1;
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end
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else
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begin
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value := 0;
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end
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counter := 0;
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while counter < 3 do
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counter := counter + 1;
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repeat
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counter := counter - 1;
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until counter = 0;
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writeLn(value);
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writeLn(counter);
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```
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代码块身份：输出片段
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```text
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1
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0
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```
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### `for` 的几种主干写法
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<!-- tags: 循环写法, 遍历数组, 计数循环, 倒着循环, 遍历键值 -->
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最基础的递增循环：
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代码块身份：可直接照写示例
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```tsl
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sum := 0;
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for i := 0 to 2 do
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sum := sum + i;
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writeLn(sum);
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```
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代码块身份：输出片段
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```text
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3
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```
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带 `step` 的递增循环：
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代码块身份：可直接照写示例
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```tsl
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sum := 0;
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for i := 1 to 5 step 2 do
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sum := sum + i;
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writeLn(sum);
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```
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输出说明：
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- 输出 `9`
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代码块身份：输出片段
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```text
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9
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```
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带 `step` 的 `downto` 递减循环：
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代码块身份：可直接照写示例
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```tsl
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sum := 0;
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for i := 5 downto 1 step 2 do
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sum := sum + i;
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writeLn(sum);
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```
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输出说明：
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- 输出 `9`
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代码块身份：输出片段
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```text
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9
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```
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数组遍历：
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代码块身份：可直接照写示例
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```tsl
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numbers := array(10, 20, 30);
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for i, value in numbers do
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writeLn(i * 100 + value);
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```
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输出说明：
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- 依次输出 `10`、`120`、`230`
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- 这说明 `for i, value in numbers` 里的 `i` 从 `0` 开始
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代码块身份：输出片段
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```text
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10
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120
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230
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```
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### `break` 与 `continue`
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<!-- tags: 跳出循环, 提前退出循环, 跳过本次, 结束循环 -->
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`break`：
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代码块身份：可直接照写示例
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```tsl
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i := 0;
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sum := 0;
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while true do
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begin
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i := i + 1;
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if i > 3 then
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break;
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sum := sum + i;
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end
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writeLn(sum);
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writeLn(i);
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```
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输出说明：
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- `sum` 输出 `6`
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- `i` 输出 `4`
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代码块身份：输出片段
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```text
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6
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4
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```
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`continue`：
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代码块身份：可直接照写示例
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```tsl
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i := 0;
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sum := 0;
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while i < 4 do
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begin
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i := i + 1;
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if i = 2 then
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continue;
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sum := sum + i;
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end
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writeLn(sum);
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```
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输出说明：
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- 输出 `8`
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代码块身份：输出片段
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```text
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8
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```
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### `case` 语句形态
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<!-- tags: 多分支, 分支判断, switch 怎么写, 多条件选择 -->
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普通分支：
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代码块身份：可直接照写示例
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```tsl
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a := 2;
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case a of
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1:
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writeLn("one");
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2:
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writeLn("two");
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else
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writeLn("other");
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end
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```
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输出说明：
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- 输出 `two`
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代码块身份：输出片段
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```text
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two
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```
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并列标签与区间：
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代码块身份：可直接照写示例
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```tsl
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a := 4;
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case a of
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1, 2:
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writeLn("small");
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3 to 5:
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writeLn("mid");
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else
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writeLn("other");
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end
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```
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输出说明：
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- 输出 `mid`
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代码块身份：输出片段
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```text
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mid
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```
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`case` 表达式形态：
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代码块身份：可直接照写示例
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```tsl
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a := 3;
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label_value := case a of
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1, 2:
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"small";
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3, 4:
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"mid";
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else
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"other";
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end;
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writeLn(label_value);
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```
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输出说明：
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- 输出 `mid`
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代码块身份：输出片段
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```text
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mid
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```
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说明：
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- 表达式形态可以放在赋值右侧。
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- 表达式形态的每个分支只写单条表达式/单条语句，不写 `begin ... end` 语句段。
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- 赋值语句整体以 `end;` 收尾。
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### `try ... except`
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<!-- tags: 捕获异常, 出错处理, 抓错误, 异常不中断 -->
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代码块身份：可直接照写示例
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```tsl
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writeLn("before");
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try
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raise "boom";
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except
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writeLn("caught");
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writeLn(exceptObject.errInfo);
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end
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writeLn("after");
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```
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输出说明：
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- 先输出 `before`
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- 再输出 `caught`
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- `exceptObject.errInfo` 输出包含 `raise: boom` 的错误信息
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- 最后继续输出 `after`
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代码块身份：输出片段
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```text
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before
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caught
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raise: boom
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after
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```
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`exceptObject` 的扩展字段：
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代码块身份：可直接照写示例
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```tsl
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try
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raise "boom";
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except
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writeLn(exceptObject.errLine);
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writeLn(exceptObject.errNo);
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end
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```
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输出说明：
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- `exceptObject.errLine` 输出 `4`
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- `exceptObject.errNo` 输出 `2`
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- 说明异常对象除了 `errInfo` 以外，也能直接提供出错行号和错误号
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代码块身份：输出片段
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```text
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4
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2
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```
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### `try ... finally`
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<!-- tags: 收尾处理, 无论如何都执行, 释放资源, 清理动作 -->
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正常路径：
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代码块身份：可直接照写示例
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```tsl
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writeLn("before");
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try
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writeLn("body");
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finally
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writeLn("finally");
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end
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writeLn("after");
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```
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输出说明：
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- 依次输出 `before`、`body`、`finally`、`after`
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代码块身份：输出片段
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```text
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before
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body
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finally
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after
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```
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报错路径：
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代码块身份：可直接照写示例
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```tsl
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writeLn("before");
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try
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writeLn("body");
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raise "boom";
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finally
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writeLn("finally");
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end
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writeLn("after");
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```
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输出说明：
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- 先输出 `before`
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- 再输出 `body`
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- 然后仍会输出 `finally`
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- 随后脚本报错终止，`after` 不会执行
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代码块身份：输出片段
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```text
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before
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body
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finally
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```
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### `raise`
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<!-- tags: 抛异常, 主动报错, 中断执行, 扔错误 -->
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代码块身份：可直接照写示例
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```tsl
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writeLn("before");
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raise "boom";
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writeLn("after");
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```
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输出说明：
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- 先输出 `before`
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- 随后脚本报错终止，`after` 不会执行
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代码块身份：输出片段
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```text
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before
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```
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## 默认生成模板
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最短条件分支的默认骨架如下：
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代码块身份：可直接照写示例
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```tsl
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flag := 1;
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if flag > 0 then
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begin
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value := 1;
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end
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else
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begin
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value := 0;
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end
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```
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## 禁止项
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- 在 `else` 前面误加分号。
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- 生成没有分号的裸分支赋值，例如 `then value := 1 else ...`；带 `else` 时用块式分支。
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- 以为 `try ... finally` 会吞掉异常。
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- 在还没搞清表达式规则前，先把复杂业务函数塞进条件里。
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- 把控制流问题和函数文件模型问题混在一起排查。
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代码块身份：反例 / 不可照写
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```text
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if flag > 0 then
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value := 1;
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else
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value := 0;
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```
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上面这种写法会编译失败，因为 `else` 前面的分号会让 `if` 语句在上一行提前结束。生成带 `else` 的赋值分支时，不要改成省略分号的裸分支；使用前文的块式分支。
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