Initial commit

Co-Authored-By: Claude <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,37 @@
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+go.work.sum
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# Compiled binary
+gselect
+
+# OS generated files
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db

PRD.md

@@ -0,0 +1,354 @@
+# gselect —— 交互式 CLI 单选器
+
+**Product Requirements Document (PRD)**
+
+---
+
+## 1. 产品概述
+
+### 1.1 产品定位
+
+`gselect` 是一个 **基于 Golang + Bubble Tea 的交互式命令行选择器**，
+以 **单选为核心**，用于补全 shell 脚本中缺失的“美观、稳定、可控”的交互选择能力。
+
+*其定位类似于 **`fzf`**，但目标是：*
+
+* **更简单**
+* **更容易嵌入 shell 脚本**
+* **更容易维护与二次开发**
+
+---
+
+### 1.2 目标用户
+
+* 运维工程师
+* 后端 / 工具链开发者
+* 编写 shell / bash / zsh / fish 脚本的用户
+* CLI 工具作者
+
+---
+
+### 1.3 非目标
+
+* 不做复杂 TUI 框架
+* 不做 REPL
+* 不做表格 / 分屏 / 树状 UI
+* 不支持鼠标操作
+* 不做插件系统
+
+---
+
+## 2. 设计原则（强约束）
+
+1. **Unix 风格**
+
+    * stdin 输入
+    * stdout 输出
+    * exit code 表达状态
+
+2. **单选优先**
+
+    * 单选是默认行为
+    * 多选只是可选扩展
+
+3. **Shell 友好**
+
+    * 输出可直接被 `$(...)`、`mapfile`、`read` 使用
+    * 不输出多余日志
+
+4. **接口极简**
+
+    * 参数少
+    * 行为直观
+    * 无配置文件依赖
+
+---
+
+## 3. 使用方式总览
+
+### 3.1 基础用法（默认单选）
+
+```bash
+printf "apple\nbanana\norange\n" | gselect
+```
+
+用户交互：
+
+* ↑ ↓ 移动
+* Enter 确认
+* Esc / Ctrl+C 取消
+
+stdout：
+
+```text
+banana
+```
+
+exit code：
+
+* `0`：成功选择
+* `1`：用户取消 / 无选择
+
+---
+
+## 4. 输入规范（stdin）
+
+### 4.1 输入格式
+
+* 每行一个选项
+* 空行忽略
+* 原样显示，不做 trim / escape
+
+```text
+option A
+option B
+option C
+```
+
+---
+
+### 4.2 可选 Key-Value 输入（扩展）
+
+```text
+Apple|apple
+Banana|banana
+```
+
+启用参数：
+
+```bash
+gselect --kv
+```
+
+* UI 显示：`Apple`
+* 输出结果：`apple`
+
+---
+
+## 5. 输出规范（stdout）
+
+### 5.1 默认输出
+
+* 输出 **选中项的值**
+* 单行文本
+* 不包含换行以外的任何字符
+
+```text
+banana
+```
+
+---
+
+### 5.2 输出索引
+
+```bash
+gselect --index
+```
+
+stdout：
+
+```text
+1
+```
+
+（索引从 `0` 开始）
+
+---
+
+## 6. 退出状态（exit code）
+
+| code | 含义                 |
+| ---- | ------------------ |
+| 0    | 用户成功选择             |
+| 1    | 用户取消（Esc / Ctrl+C） |
+| 2    | 输入为空 / 无可选项        |
+| 3    | 参数错误               |
+
+---
+
+## 7. 命令行参数设计
+
+### 7.1 参数一览
+
+| 参数                | 说明                |
+| ----------------- | ----------------- |
+| `--title`         | 顶部标题              |
+| `--index`         | 输出索引而非值           |
+| `--default`       | 默认选中值             |
+| `--default-index` | 默认选中索引            |
+| `--no-search`     | 禁用搜索过滤            |
+| `--kv`            | 启用 label|value 模式 |
+| `--version`       | 显示版本              |
+| `--help`          | 帮助信息              |
+
+---
+
+### 7.2 参数示例
+
+#### 设置标题
+
+```bash
+gselect --title "Select a branch"
+```
+
+#### 默认选中
+
+```bash
+gselect --default "banana"
+gselect --default-index 1
+```
+
+#### 输出索引
+
+```bash
+gselect --index
+```
+
+#### 禁用搜索
+
+```bash
+gselect --no-search
+```
+
+---
+
+## 8. 交互设计
+
+### 8.1 键位定义（固定，不可配置）
+
+| 键      | 行为        |
+| ------ | --------- |
+| ↑ / k  | 上移        |
+| ↓ / j  | 下移        |
+| Enter  | 确认        |
+| Esc    | 取消        |
+| Ctrl+C | 取消        |
+| 字符输入   | 搜索过滤（如启用） |
+
+---
+
+### 8.2 搜索行为
+
+* 默认启用
+* 子串匹配（不要求 fuzzy）
+* 实时过滤
+* 可通过 `--no-search` 禁用
+
+---
+
+## 9. UI 设计规范
+
+### 9.1 技术选型
+
+* `bubbletea`
+* `bubbles/list`
+* `lipgloss`
+
+---
+
+### 9.2 UI 元素
+
+* 顶部：标题（可选）
+* 中部：列表
+* 底部：简要提示（↑↓ Enter Esc）
+
+---
+
+### 9.3 风格要求
+
+* 简洁
+* 对比清晰
+* 不使用 Emoji
+* 颜色适配暗色终端
+
+---
+
+## 10. 内部模型（设计指导）
+
+### 10.1 核心数据结构（建议）
+
+```go
+type Item struct {
+    Label string
+    Value string
+    Index int
+}
+```
+
+```go
+type Model struct {
+    List      list.Model
+    Selected  *Item
+    Cancelled bool
+}
+```
+
+---
+
+### 10.2 退出逻辑
+
+* Enter → 输出 → `os.Exit(0)`
+* Esc / Ctrl+C → `os.Exit(1)`
+* 无输入 → `os.Exit(2)`
+
+---
+
+## 11. Shell 使用示例
+
+### 11.1 基础
+
+```bash
+choice=$(ls | gselect) || exit 1
+echo "$choice"
+```
+
+---
+
+### 11.2 Git 分支选择
+
+```bash
+branch=$(git branch --format='%(refname:short)' | gselect)
+git checkout "$branch"
+```
+
+---
+
+### 11.3 输出索引
+
+```bash
+idx=$(printf "a\nb\nc\n" | gselect --index)
+```
+
+---
+
+## 12. 非功能性要求
+
+* 启动时间 < 50ms
+* 单文件二进制
+* 无运行时依赖
+* 支持 Linux / macOS
+* Go ≥ 1.21
+
+---
+
+## 13. 未来扩展（不在本期）
+
+* 多选模式
+* 自定义分隔符
+* 预览窗
+* JSON 输入
+
+---
+
+## 14. 成功标准（验收）
+
+* 可在 shell 中稳定使用
+* Ctrl+C 不污染终端
+* stdout 可直接被脚本消费
+* 用户无需文档即可理解基本操作
+
+---
+
+## 15. 一句话总结
+
+> **一个“像 fzf 一样好用，但更简单、更可控、更适合脚本”的 CLI 单选器。**

go.mod

@@ -0,0 +1,29 @@
+module go-gselect
+
+go 1.25
+
+require (
+	github.com/charmbracelet/bubbles v0.17.1
+	github.com/charmbracelet/bubbletea v0.25.0
+	github.com/charmbracelet/lipgloss v0.9.1
+)
+
+require (
+	github.com/atotto/clipboard v0.1.4 // indirect
+	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
+	github.com/containerd/console v1.0.4-0.20230313162750-1ae8d489ac81 // indirect
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-isatty v0.0.18 // indirect
+	github.com/mattn/go-localereader v0.0.1 // indirect
+	github.com/mattn/go-runewidth v0.0.15 // indirect
+	github.com/muesli/ansi v0.0.0-20211018074035-2e021307bc4b // indirect
+	github.com/muesli/cancelreader v0.2.2 // indirect
+	github.com/muesli/reflow v0.3.0 // indirect
+	github.com/muesli/termenv v0.15.2 // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
+	github.com/sahilm/fuzzy v0.1.1-0.20230530133925-c48e322e2a8f // indirect
+	golang.org/x/sync v0.1.0 // indirect
+	golang.org/x/sys v0.12.0 // indirect
+	golang.org/x/term v0.6.0 // indirect
+	golang.org/x/text v0.3.8 // indirect
+)

go.sum

@@ -0,0 +1,46 @@
+github.com/atotto/clipboard v0.1.4 h1:EH0zSVneZPSuFR11BlR9YppQTVDbh5+16AmcJi4g1z4=
+github.com/atotto/clipboard v0.1.4/go.mod h1:ZY9tmq7sm5xIbd9bOK4onWV4S6X0u6GY7Vn0Yu86PYI=
+github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
+github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
+github.com/charmbracelet/bubbles v0.17.1 h1:0SIyjOnkrsfDo88YvPgAWvZMwXe26TP6drRvmkjyUu4=
+github.com/charmbracelet/bubbles v0.17.1/go.mod h1:9HxZWlkCqz2PRwsCbYl7a3KXvGzFaDHpYbSYMJ+nE3o=
+github.com/charmbracelet/bubbletea v0.25.0 h1:bAfwk7jRz7FKFl9RzlIULPkStffg5k6pNt5dywy4TcM=
+github.com/charmbracelet/bubbletea v0.25.0/go.mod h1:EN3QDR1T5ZdWmdfDzYcqOCAps45+QIJbLOBxmVNWNNg=
+github.com/charmbracelet/lipgloss v0.9.1 h1:PNyd3jvaJbg4jRHKWXnCj1akQm4rh8dbEzN1p/u1KWg=
+github.com/charmbracelet/lipgloss v0.9.1/go.mod h1:1mPmG4cxScwUQALAAnacHaigiiHB9Pmr+v1VEawJl6I=
+github.com/containerd/console v1.0.4-0.20230313162750-1ae8d489ac81 h1:q2hJAaP1k2wIvVRd/hEHD7lacgqrCPS+k8g1MndzfWY=
+github.com/containerd/console v1.0.4-0.20230313162750-1ae8d489ac81/go.mod h1:YynlIjWYF8myEu6sdkwKIvGQq+cOckRm6So2avqoYAk=
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
+github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
+github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
+github.com/mattn/go-isatty v0.0.18 h1:DOKFKCQ7FNG2L1rbrmstDN4QVRdS89Nkh85u68Uwp98=
+github.com/mattn/go-isatty v0.0.18/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-localereader v0.0.1 h1:ygSAOl7ZXTx4RdPYinUpg6W99U8jWvWi9Ye2JC/oIi4=
+github.com/mattn/go-localereader v0.0.1/go.mod h1:8fBrzywKY7BI3czFoHkuzRoWE9C+EiG4R1k4Cjx5p88=
+github.com/mattn/go-runewidth v0.0.12/go.mod h1:RAqKPSqVFrSLVXbA8x7dzmKdmGzieGRCM46jaSJTDAk=
+github.com/mattn/go-runewidth v0.0.15 h1:UNAjwbU9l54TA3KzvqLGxwWjHmMgBUVhBiTjelZgg3U=
+github.com/mattn/go-runewidth v0.0.15/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
+github.com/muesli/ansi v0.0.0-20211018074035-2e021307bc4b h1:1XF24mVaiu7u+CFywTdcDo2ie1pzzhwjt6RHqzpMU34=
+github.com/muesli/ansi v0.0.0-20211018074035-2e021307bc4b/go.mod h1:fQuZ0gauxyBcmsdE3ZT4NasjaRdxmbCS0jRHsrWu3Ho=
+github.com/muesli/cancelreader v0.2.2 h1:3I4Kt4BQjOR54NavqnDogx/MIoWBFa0StPA8ELUXHmA=
+github.com/muesli/cancelreader v0.2.2/go.mod h1:3XuTXfFS2VjM+HTLZY9Ak0l6eUKfijIfMUZ4EgX0QYo=
+github.com/muesli/reflow v0.3.0 h1:IFsN6K9NfGtjeggFP+68I4chLZV2yIKsXJFNZ+eWh6s=
+github.com/muesli/reflow v0.3.0/go.mod h1:pbwTDkVPibjO2kyvBQRBxTWEEGDGq0FlB1BIKtnHY/8=
+github.com/muesli/termenv v0.15.2 h1:GohcuySI0QmI3wN8Ok9PtKGkgkFIk7y6Vpb5PvrY+Wo=
+github.com/muesli/termenv v0.15.2/go.mod h1:Epx+iuz8sNs7mNKhxzH4fWXGNpZwUaJKRS1noLXviQ8=
+github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
+github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
+github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
+github.com/sahilm/fuzzy v0.1.1-0.20230530133925-c48e322e2a8f h1:MvTmaQdww/z0Q4wrYjDSCcZ78NoftLQyHBSLW/Cx79Y=
+github.com/sahilm/fuzzy v0.1.1-0.20230530133925-c48e322e2a8f/go.mod h1:VFvziUEIMCrT6A6tw2RFIXPXXmzXbOsSHF0DOI8ZK9Y=
+golang.org/x/sync v0.1.0 h1:wsuoTGHzEhffawBOhz5CYhcrV4IdKZbEyZjBMuTp12o=
+golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
+golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.6.0 h1:clScbb1cHjoCkyRbWwBEUZ5H/tIFu5TAXIqaZD0Gcjw=
+golang.org/x/term v0.6.0/go.mod h1:m6U89DPEgQRMq3DNkDClhWw02AUbt2daBVO4cn4Hv9U=
+golang.org/x/text v0.3.8 h1:nAL+RVCQ9uMn3vJZbV+MRnydTJFPf8qqY42YiA6MrqY=
+golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=

main.go

@@ -0,0 +1,334 @@
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/charmbracelet/bubbles/list"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+)
+
+const version = "0.1.0"
+
+type Item struct {
+	Label string
+	Value string
+	Index int
+}
+
+func (i Item) FilterValue() string {
+	return i.Label
+}
+
+type Config struct {
+	Title        string
+	DefaultValue string
+	DefaultIndex int
+	OutputIndex  bool
+	NoSearch     bool
+	KVMode       bool
+}
+
+type Model struct {
+	items     []Item
+	list      list.Model
+	selected  *Item
+	cancelled bool
+	config    Config
+}
+
+type itemDelegate struct {
+	selectedStyle lipgloss.Style
+	normalStyle   lipgloss.Style
+}
+
+func (d itemDelegate) Height() int  { return 1 }
+func (d itemDelegate) Spacing() int { return 0 }
+func (d itemDelegate) Update(_ tea.Msg, m *list.Model) tea.Cmd {
+	return nil
+}
+
+func (d itemDelegate) Render(w io.Writer, m list.Model, index int, listItem list.Item) {
+	item, ok := listItem.(Item)
+	if !ok {
+		return
+	}
+
+	cursor := "  "
+	style := d.normalStyle
+	if index == m.Index() {
+		cursor = "> "
+		style = d.selectedStyle
+	}
+
+	fmt.Fprint(w, style.Render(cursor+item.Label))
+}
+
+func newModel(items []Item, config Config, selectedIndex int) Model {
+	listItems := make([]list.Item, 0, len(items))
+	for _, item := range items {
+		listItems = append(listItems, item)
+	}
+
+	delegate := itemDelegate{
+		selectedStyle: lipgloss.NewStyle().Bold(true).Foreground(lipgloss.Color("2")),
+		normalStyle:   lipgloss.NewStyle(),
+	}
+
+	l := list.New(listItems, delegate, 0, 0)
+	l.SetShowHelp(false)
+	l.SetShowStatusBar(false)
+	l.SetShowPagination(false)
+	l.SetShowTitle(false)
+	l.SetFilteringEnabled(!config.NoSearch)
+	l.SetShowFilter(!config.NoSearch)
+	l.KeyMap.Quit.SetEnabled(false)
+	l.KeyMap.ForceQuit.SetEnabled(false)
+
+	if selectedIndex >= 0 && selectedIndex < len(items) {
+		l.Select(selectedIndex)
+	}
+
+	return Model{
+		items:  items,
+		list:   l,
+		config: config,
+	}
+}
+
+func (m Model) Init() tea.Cmd {
+	return nil
+}
+
+func (m Model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		switch msg.Type {
+		case tea.KeyEnter:
+			selected := m.list.SelectedItem()
+			if selectedItem, ok := selected.(Item); ok {
+				m.selected = &selectedItem
+				return m, tea.Quit
+			}
+			m.cancelled = true
+			return m, tea.Quit
+		case tea.KeyEsc, tea.KeyCtrlC:
+			m.cancelled = true
+			return m, tea.Quit
+		}
+	case tea.WindowSizeMsg:
+		heightUsed := 1
+		if m.config.Title != "" {
+			heightUsed++
+		}
+		m.list.SetSize(msg.Width, max(0, msg.Height-heightUsed))
+	}
+
+	var cmd tea.Cmd
+	m.list, cmd = m.list.Update(msg)
+	return m, cmd
+}
+
+func (m Model) View() string {
+	var b strings.Builder
+
+	if m.config.Title != "" {
+		titleStyle := lipgloss.NewStyle().Bold(true)
+		b.WriteString(titleStyle.Render(m.config.Title))
+		b.WriteString("\n")
+	}
+
+	b.WriteString(m.list.View())
+
+	helpStyle := lipgloss.NewStyle().Foreground(lipgloss.Color("8"))
+	b.WriteString("\n")
+	b.WriteString(helpStyle.Render("↑/↓ (j/k) Enter Esc"))
+
+	return b.String()
+}
+
+func readItems(r io.Reader, kvMode bool) ([]Item, error) {
+	scanner := bufio.NewScanner(r)
+	items := []Item{}
+	index := 0
+	for scanner.Scan() {
+		line := scanner.Text()
+		if line == "" {
+			continue
+		}
+
+		label := line
+		value := line
+		if kvMode {
+			if sep := strings.Index(line, "|"); sep >= 0 {
+				label = line[:sep]
+				value = line[sep+1:]
+			}
+		}
+
+		items = append(items, Item{Label: label, Value: value, Index: index})
+		index++
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	return items, nil
+}
+
+func parseFlags() (Config, bool, bool, bool, bool, error) {
+	var cfg Config
+	var showHelp bool
+	var showVersion bool
+	var defaultValueSet bool
+	var defaultIndexSet bool
+
+	fs := flag.NewFlagSet(os.Args[0], flag.ContinueOnError)
+	fs.SetOutput(io.Discard)
+
+	fs.StringVar(&cfg.Title, "title", "", "Title shown above the list")
+	fs.BoolVar(&cfg.OutputIndex, "index", false, "Output index instead of value")
+	fs.BoolVar(&cfg.NoSearch, "no-search", false, "Disable search filtering")
+	fs.BoolVar(&cfg.KVMode, "kv", false, "Enable label|value input mode")
+	fs.BoolVar(&showVersion, "version", false, "Show version")
+	fs.BoolVar(&showHelp, "help", false, "Show help")
+
+	fs.Func("default", "Default selected value", func(value string) error {
+		cfg.DefaultValue = value
+		defaultValueSet = true
+		return nil
+	})
+
+	fs.Func("default-index", "Default selected index", func(value string) error {
+		parsed, err := strconv.Atoi(value)
+		if err != nil {
+			return err
+		}
+		cfg.DefaultIndex = parsed
+		defaultIndexSet = true
+		return nil
+	})
+
+	if err := fs.Parse(os.Args[1:]); err != nil {
+		return cfg, false, false, false, false, err
+	}
+
+	return cfg, showHelp, showVersion, defaultValueSet, defaultIndexSet, nil
+}
+
+func printHelp(w io.Writer) {
+	help := `gselect - interactive CLI selector
+
+Usage:
+  gselect [flags]
+
+Flags:
+  --title string          Title shown above the list
+  --index                 Output index instead of value
+  --default string        Default selected value
+  --default-index int     Default selected index
+  --no-search             Disable search filtering
+  --kv                    Enable label|value input mode
+  --version               Show version
+  --help                  Show help
+`
+	fmt.Fprint(w, help)
+}
+
+func clamp(value, minValue, maxValue int) int {
+	if value < minValue {
+		return minValue
+	}
+	if value > maxValue {
+		return maxValue
+	}
+	return value
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func main() {
+	cfg, showHelp, showVersion, defaultValueSet, defaultIndexSet, err := parseFlags()
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(3)
+	}
+
+	if showHelp {
+		printHelp(os.Stdout)
+		os.Exit(0)
+	}
+
+	if showVersion {
+		fmt.Fprintf(os.Stdout, "gselect %s\n", version)
+		os.Exit(0)
+	}
+
+	if defaultValueSet && defaultIndexSet {
+		fmt.Fprintln(os.Stderr, "--default and --default-index cannot be used together")
+		os.Exit(3)
+	}
+
+	items, err := readItems(os.Stdin, cfg.KVMode)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(3)
+	}
+	if len(items) == 0 {
+		os.Exit(2)
+	}
+
+	selectedIndex := 0
+	if defaultValueSet {
+		for i, item := range items {
+			if item.Value == cfg.DefaultValue {
+				selectedIndex = i
+				break
+			}
+		}
+	} else if defaultIndexSet {
+		selectedIndex = clamp(cfg.DefaultIndex, 0, len(items)-1)
+	}
+
+	model := newModel(items, cfg, selectedIndex)
+	tty, ttyErr := os.OpenFile("/dev/tty", os.O_RDWR, 0)
+	if ttyErr != nil {
+		fmt.Fprintln(os.Stderr, "failed to open /dev/tty for input/output")
+		os.Exit(3)
+	}
+	defer tty.Close()
+
+	program := tea.NewProgram(model, tea.WithAltScreen(), tea.WithInput(tty), tea.WithOutput(tty))
+	finalModel, runErr := program.Run()
+	if runErr != nil {
+		if runErr == tea.ErrProgramKilled {
+			os.Exit(1)
+		}
+		fmt.Fprintln(os.Stderr, runErr)
+		os.Exit(1)
+	}
+
+	result := finalModel.(Model)
+	if result.cancelled || result.selected == nil {
+		os.Exit(1)
+	}
+
+	if cfg.OutputIndex {
+		fmt.Fprintln(os.Stdout, result.selected.Index)
+		os.Exit(0)
+	}
+
+	fmt.Fprintln(os.Stdout, result.selected.Value)
+}