Crate standout_input 

Declarative input collection for CLI applications.

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.

Quick Start

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

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

Features

• editor (default) - Enable [EditorCollector] for editor-based input
• simple-prompts (default) - Enable basic terminal prompts
• inquire - Enable rich TUI prompts via the inquire crate

Architecture

The crate is built around the InputCollector trait, which all input sources implement. Sources are composed into InputChains that try each source in order until one provides input.

InputChain
├── ArgSource      → None (not provided)
├── StdinSource    → None (not piped)
├── EditorSource   → Some("user input") ← returns this
└── DefaultSource  → (not reached)

Questionnaire answer sheets

The questionnaire module renders an application-defined questionnaire — scalar fields plus nested and repeatable groups — as an editable prose answer sheet, collects answers interactively or from a named file or explicit stdin, and decodes every submission through one shared validation pipeline keyed by stable identity (with indexed occurrence paths for repeated items). See the module documentation for the format, the application/library ownership boundary, and the exact-match compatibility contract.

Testing

All sources accept mock implementations for testing:

use standout_input::{StdinSource, env::MockStdin};

// Test with simulated piped input
let source = StdinSource::with_reader(MockStdin::piped("test input"));

Re-exports

pub use sources::read_if_piped;

pub use sources::ArgSource;

pub use sources::ClipboardSource;

pub use sources::DefaultSource;

pub use sources::EnvSource;

pub use sources::FlagSource;

pub use sources::StdinSource;

pub use sources::EditorRunner;

pub use sources::EditorSource;

pub use sources::MockEditorResult;

pub use sources::MockEditorRunner;

pub use sources::ConfirmPromptSource;

pub use sources::MockTerminal;

pub use sources::TerminalIO;

pub use sources::TextPromptSource;

pub use env::MockClipboard;

pub use env::MockEnv;

pub use env::MockStdin;

pub use env::reset_default_clipboard_reader;

pub use env::reset_default_stdin_reader;

pub use env::set_default_clipboard_reader;

pub use env::set_default_stdin_reader;

pub use env::DefaultClipboard;

pub use env::DefaultStdin;

Modules

env

Environment abstractions for testability.

questionnaire

Questionnaire answer sheets: render a prose questionnaire, collect answers interactively or from a document, and decode them by stable identity through one shared validation pipeline. Structs that derive Questionnaire lower to this same runtime model and fill themselves from validated Answers without a serde boundary.

sources

Input source implementations.

Structs

InputChain

Chain multiple input sources with fallback behavior.

Inputs

Name-keyed storage for resolved inputs.

PromptContext

Context the source passes to a PromptResponder.

ResolvedInput

Information about how input was resolved.

ScriptedResponder

A position-based scripted responder.

Enums

InputError

Errors that can occur during input collection.

InputSourceKind

The kind of source that provided input.

MissingInput

Error returned when a named input is missing or stored under a different type.

PromptKind

The kind of prompt being responded to.

PromptResponse

A response a PromptResponder can return.

Traits

InputCollector

A source that can collect input of type T.

PromptResponder

Test seam for the .prompt() shortcut on interactive sources.

Functions

reset_default_prompt_responder

Clears the override installed by set_default_prompt_responder.

set_default_prompt_responder

Installs a process-global PromptResponder that every .prompt() call on an interactive source will route through until reset_default_prompt_responder is called.