standout-input

Declarative input collection for CLI applications.

Overview

standout-input provides a unified way to acquire user input from multiple sources—CLI arguments, stdin, environment variables, editors, and interactive prompts—with automatic fallback chains.

use standout_input::{InputChain, ArgSource, StdinSource, EditorSource};

// Try argument first, then piped stdin, then open editor
let message = InputChain::<String>::new()
    .try_source(ArgSource::new("message"))
    .try_source(StdinSource::new())
    .try_source(EditorSource::new())
    .resolve(&matches)?;

Features

• Declarative chains - Define fallback sequences without imperative logic
• Pluggable sources - Arg, stdin, env, clipboard, editor, prompts
• Validation - Chain-level and source-level validation with retry support
• Testable - All sources accept mock implementations for CI-safe testing
• Minimal deps - Core has ~2 dependencies; heavy features are opt-in

Feature Flags

Minimal Build

[dependencies]
standout-input = { version = "0.1", default-features = false }

Full Feature Set

[dependencies]
standout-input = { version = "0.1", features = ["inquire"] }

Usage

Basic Chain

use standout_input::{InputChain, ArgSource, StdinSource, DefaultSource};

let chain = InputChain::<String>::new()
    .try_source(ArgSource::new("message"))
    .try_source(StdinSource::new())
    .default("default message".to_string());

let value = chain.resolve(&matches)?;

With Validation

let chain = InputChain::<String>::new()
    .try_source(ArgSource::new("email"))
    .try_source(TextPromptSource::new("Email: "))
    .validate(|s| s.contains('@'), "Must be a valid email");

Testing with Mocks

use standout_input::{StdinSource, MockStdin, EnvSource, MockEnv};

// Simulate piped input
let source = StdinSource::with_reader(MockStdin::piped("test content"));

// Simulate terminal (no piped input)
let source = StdinSource::with_reader(MockStdin::terminal());

// Simulate environment variable
let env = MockEnv::new().with_var("TOKEN", "secret");
let source = EnvSource::with_reader("TOKEN", env);

Available Sources

Non-Interactive (always available)

Editor (editor feature, default)

Simple Prompts (simple-prompts feature, default)

Inquire (inquire feature)

Documentation

• Introduction to Input - Getting started guide
• Backends - Detailed backend documentation and custom implementations

License

MIT