# xl-md 规范

> 源文件是 `*.xl.md`，UTF-8 无 BOM，LF。

## 完整 case
````md
# dependencies
```xl
import { level } from "./util.xl.md"
```

```ts
import _ from "lodash";
import { readFileSync as rf } from "node:fs";
```
## csharp
```csharp
using System.Text.Json;
```

# namespace demo
demo 包的用途说明，会成为 LLM 生成的上下文。

# type MemberKind = "field" | "property" | "method"
成员种类。

## csharp
```csharp
using MemberKind = string;
```

# const MAX_DEPTH:int = 8
默认代码块深度上限。
## csharp
```csharp
public static int MAX_DEPTH = 8;
```

# const RULES:ReadonlyArray<string>
规则码清单；初始值用默认语言代码块给出。
```ts
[
  "E1001",
  "E1002",
]
```

# method loadText:(path:string, encoding?:string)=>string
同步读取文本；
```ts
return rf(path, encoding ?? "utf8");
```

## csharp
```csharp
return File.ReadAllText(path, (encoding ?? "utf8") switch {
  "utf8" => new UTF8Encoding(false),
  _ => new UTF8Encoding(false)
});
```

# method pickFirst:<T>(items:Array<T>)=>T
取第一个元素
```ts
return items[0]!;
```

# enum color
可见颜色
- case red
红色
- case green = 2
绿色
- case blue
蓝色

## python
使用字符串表达

# interface printable

## readonly field kind:"printable"

## readonly field id:string

## field note?:string

## method print:()=>string

# interface named extends printable

## field tag:string

## method describe:()=>string

# class point

## field x:int = 0
横坐标。

## field y:int = 0
纵坐标。

## method move:(dx:int, dy:int)=>void
把点移动 (dx, dy)。
```ts
this.x = this.x + dx;
this.y = this.y + dy;
```

## constructor:(x?:int, y?:int)=>void
```ts
this.x = x ?? 0;
this.y = y ?? 0;
```

# class box<T extends object> extends point implements printable

## readonly field kind:"printable" = "printable"

## field id:string = "box"

## field tags:Array<string> = []

## field logLevel:level = level.info

## static readonly field ORIGIN:string = "0,0"

## private field raw:int = 0

## static field count:int = 0

## property label:string = "unnamed"
### get
### private set

## property score:int
### get
```ts
return this.raw;
```
### set
```ts
if (value < 0) throw new Error("score must be >= 0");
this.raw = value;
```

## method print:()=>string
```ts
return this.id;
```

## method chunk2:(list:Array<int>)=>Array<Array<int>>
按两个一组切分。
```ts
return _.chunk(list, 2);
```

## method load:async (url:string)=>string
异步读取。
```ts
const r = await fetch(url);
return r.text();
```

## method tick:()=>int
每调用一次前进一格。
```ts
yield 1;
yield 2;
```

## private method clamp:(v:int)=>int
```ts
return v < 0 ? 0 : v;
```

# class cache<K extends string, V = any>

## field hits:int = 0

## field data:Map<K,V>
```ts
new Map()
```

# statement
模块被加载时执行一次：把第一条规则码打出来。
```ts
console.log(pickFirst(RULES));
```

## csharp
```csharp
Console.WriteLine(pickFirst(RULES));
```
````

## 输出 ts 完整代码

```ts
// @generated by xl from demo.xl.md
// xl:sha256:<key>
// DO NOT EDIT — 修改请改 xl.md 并重新生成

import _ from "lodash";
import { readFileSync as rf } from "node:fs";
import { level } from "./util";

export type MemberKind = "field" | "property" | "method";

export const MAX_DEPTH: number = 8;

export const RULES: readonly string[] = [
  "E1001",
  "E1002",
];

export function loadText(path: string, encoding?: string): string {
  return rf(path, encoding ?? "utf8");
}

export function pickFirst<T>(items: T[]): T {
  return items[0]!;
}

export enum color {
  red,
  green = 2,
  blue
}

export interface printable {
  readonly kind: "printable";
  readonly id: string;
  note?: string;
  print(): string;
}

export interface named extends printable {
  tag: string;
  describe(): string;
}

export class point {
  public x: number = 0;
  public y: number = 0;

  public move(dx: number, dy: number): void {
    this.x = this.x + dx;
    this.y = this.y + dy;
  }

  constructor(x?: number, y?: number) {
    this.x = x ?? 0;
    this.y = y ?? 0;
  }
}

export class box<T extends object> extends point implements printable {
  public readonly kind: "printable" = "printable";
  public id: string = "box";
  public tags: string[] = [];
  public logLevel: level = level.info;
  public static readonly ORIGIN: string = "0,0";
  private raw: number = 0;
  public static count: number = 0;
  #label: string = "unnamed";

  public get label(): string { return this.#label; }
  private set label(value: string) { this.#label = value; }

  public get score(): number { return this.raw; }
  public set score(value: number) {
    if (value < 0) throw new Error("score must be >= 0");
    this.raw = value;
  }

  public print(): string {
    return this.id;
  }

  public chunk2(list: number[]): number[][] {
    return _.chunk(list, 2);
  }

  public async load(url: string): Promise<string> {
    const r = await fetch(url);
    return r.text();
  }

  public *tick(): Generator<number> {
    yield 1;
    yield 2;
  }

  private clamp(v: number): number {
    return v < 0 ? 0 : v;
  }
}

export class cache<K extends string, V = any> {
  public hits: number = 0;
  public data: Map<K, V> = new Map();
}

console.log(pickFirst(RULES));
```