From fd01d78d3d021edadd54c8c10f8c25a6d040a9a1 Mon Sep 17 00:00:00 2001
From: Mplan <mplan_@outlook.com>
Date: Fri, 12 Jun 2026 18:57:10 +0800
Subject: [PATCH] feat: add version flag to CLI, enhance error handling for
 stdin and argument parsing

---
 README.md                  | 26 +++++++++++++-------------
 package.json               |  3 ++-
 src/__tests__/args.test.ts |  8 ++++++++
 src/args.ts                | 18 ++++++------------
 src/main.ts                |  2 ++
 src/stdin.ts               |  2 +-
 6 files changed, 32 insertions(+), 27 deletions(-)

diff --git a/README.md b/README.md
index a67b545..fe7dc66 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,7 @@ rand -f2              # 保留 2 位小数
 | `-f[N]` | 小数位数：`-f` 默认 2 位，`-f1` = 1 位，`-f3` = 3 位 |
 | `--float [N]` | `-f` 的长形式 |
 | `-d, --dist <name>` | 概率分布，默认 `uniform` |
+| `-V, --version` | 版本信息 |
 | `-h, --help` | 帮助信息 |
 | `--` | 之后所有参数视为位置参数（用于负数） |
 
@@ -45,14 +46,13 @@ rand -f2              # 保留 2 位小数
 | poisson | `rand -d poisson` | `[λ]` | 1 |
 | exponential | `rand -d exponential` | `[λ]` | 1 |
 | hypergeometric | `rand -d hypergeometric` | `[N] [K] [n]` | 100, 50, 10 |
-
 ### 采样算法
 
 | 分布 | 算法 |
 |------|------|
-| normal | Box-Muller 变换 |
-| binomial | Bernoulli 试验求和 |
-| poisson | Knuth 算法 |
+| normal | Box-Muller 变换（双值缓存） |
+| binomial | Bernoulli 试验求和；n > 10,000 时切换为正态近似 |
+| poisson | Knuth 算法；λ > 100 时切换为正态近似（防止 exp 下溢） |
 | exponential | 逆 CDF 变换 |
 | hypergeometric | 不放回抽样模拟 |
 
@@ -87,20 +87,20 @@ rand -d hypergeometric 100 30 5
 
 # 负数范围（用 -- 分隔标志和参数）
 rand -- -10 -5
-rand -d normal -- 0 -1   # stddev 必须 > 0，会报错
-```
+rand -d normal 0 -1   # stddev 必须 > 0，会报错
 
 ## 项目结构
 
 ```
-index.ts            # 入口
+index.ts              # 入口
 src/
-  types.ts          # 类型定义与默认值
-  help.ts           # 帮助文本
-  args.ts           # 参数解析与校验
-  stdin.ts          # 管道输入读取
-  dist.ts           # 分布采样器与调度
-  main.ts           # 编排逻辑
+  types.ts            # 类型定义与默认值
+  help.ts             # 帮助文本
+  args.ts             # 参数解析与校验
+  stdin.ts            # 管道输入读取
+  dist.ts             # 分布采样器与调度
+  main.ts             # 编排逻辑
+  __tests__/          # 单元测试 (bun test)
 ```
 
 ## 构建
diff --git a/package.json b/package.json
index 5c2b6cf..96fc7a7 100644
--- a/package.json
+++ b/package.json
@@ -5,7 +5,8 @@
     "rand": "./index.ts"
   },
   "scripts": {
-    "build": "bun build ./index.ts --compile --outfile dist/rand"
+    "build": "bun build ./index.ts --compile --outfile dist/rand",
+    "test": "bun test"
   },
   "private": true,
   "devDependencies": {
diff --git a/src/__tests__/args.test.ts b/src/__tests__/args.test.ts
index bc862a8..4c270d9 100644
--- a/src/__tests__/args.test.ts
+++ b/src/__tests__/args.test.ts
@@ -35,6 +35,14 @@ describe("parseArgs", () => {
     expect(() => parseArgs(["-c", "1000001"])).toThrow();
   });
 
+  test("-c with non-finite value throws", () => {
+    expect(() => parseArgs(["-c", "Infinity"])).toThrow("invalid count: Infinity");
+  });
+
+  test("-f with out-of-range fails validation", () => {
+    expect(() => parseArgs(["-f", "101"])).toThrow("decimals must be 0–100");
+  });
+
   test("-f with no arg defaults to 2", () => {
     expect(parseArgs(["-f"]).options.decimals).toBe(2);
   });
diff --git a/src/args.ts b/src/args.ts
index 8ffdac8..dcb622b 100644
--- a/src/args.ts
+++ b/src/args.ts
@@ -122,61 +122,55 @@ export function applyPositionals(opts: Options, args: string[]): void {
 
   switch (opts.dist) {
     case "uniform": {
-      if (nums.length === 0) return;
       if (nums.length === 1) {
         opts.max = nums[0]!;
       } else if (nums.length === 2) {
         opts.min = nums[0]!;
         opts.max = nums[1]!;
-      } else {
+      } else if (nums.length > 2) {
         showError(`uniform expects 0–2 args, got ${nums.length}: ${args.join(" ")}`);
       }
       break;
     }
     case "normal": {
-      if (nums.length === 0) return;
       if (nums.length === 1) {
         opts.mean = nums[0]!;
       } else if (nums.length === 2) {
         opts.mean = nums[0]!;
         opts.stddev = nums[1]!;
-      } else {
+      } else if (nums.length > 2) {
         showError(`normal expects 0–2 args, got ${nums.length}: ${args.join(" ")}`);
       }
       break;
     }
     case "binomial": {
-      if (nums.length === 0) return;
       if (nums.length === 1) {
         opts.trials = nums[0]!;
       } else if (nums.length === 2) {
         opts.trials = nums[0]!;
         opts.prob = nums[1]!;
-      } else {
+      } else if (nums.length > 2) {
         showError(`binomial expects 0–2 args, got ${nums.length}: ${args.join(" ")}`);
       }
       break;
     }
     case "poisson": {
-      if (nums.length === 0) return;
       if (nums.length === 1) {
         opts.lambda = nums[0]!;
-      } else {
+      } else if (nums.length > 1) {
         showError(`poisson expects 0–1 arg, got ${nums.length}: ${args.join(" ")}`);
       }
       break;
     }
     case "exponential": {
-      if (nums.length === 0) return;
       if (nums.length === 1) {
         opts.lambda = nums[0]!;
-      } else {
+      } else if (nums.length > 1) {
         showError(`exponential expects 0–1 arg, got ${nums.length}: ${args.join(" ")}`);
       }
       break;
     }
     case "hypergeometric": {
-      if (nums.length === 0) return;
       if (nums.length >= 1) opts.popSize = nums[0]!;
       if (nums.length >= 2) opts.successes = nums[1]!;
       if (nums.length >= 3) opts.draws = nums[2]!;
@@ -196,6 +190,6 @@ export function applyPositionals(opts: Options, args: string[]): void {
 
 function parseNum(s: string): number {
   const n = Number(s);
-  if (isNaN(n)) showError(`not a number: ${s}`);
+  if (isNaN(n) || !isFinite(n)) showError(`not a number: ${s}`);
   return n;
 }
diff --git a/src/main.ts b/src/main.ts
index 326d12f..78a1033 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -15,6 +15,8 @@ async function main(): Promise<void> {
     const nums = parseStdinNumbers(input);
     if (nums.length > 0) {
       applyPositionals(options, nums.map(String));
+    } else if (input.trim()) {
+      console.error("rand: stdin contained non-numeric data, ignoring");
     }
   }
 
diff --git a/src/stdin.ts b/src/stdin.ts
index 59d54c0..96d7495 100644
--- a/src/stdin.ts
+++ b/src/stdin.ts
@@ -16,7 +16,7 @@ export function parseStdinNumbers(input: string): number[] {
   const nums: number[] = [];
   for (const p of parts) {
     const n = Number(p);
-    if (isNaN(n)) return []; // unrecognizable → ignore stdin
+    if (isNaN(n) || !isFinite(n)) return []; // unrecognizable → ignore stdin
     nums.push(n);
   }
   return nums;