nils-term

nils-term

Overview

Small terminal utilities shared across the workspace.

Shared helper policy

What belongs in nils-term

• Domain-neutral progress primitives that can be reused by multiple binaries.
• Structured APIs (Progress, ProgressOptions, ProgressEnabled) that callers can compose.
• Behavior that can be verified with deterministic unit/integration tests.

What stays crate-local

• Product-specific progress copy, emoji/prefix style, and section wording.
• CLI-specific policy decisions about when progress should appear for a command.
• Exit-code mapping and command-level error/warning text.

Progress

nils-term provides a minimal, RAII-friendly progress abstraction that is safe for machine-readable stdout output:

• progress is drawn to stderr by default
• with ProgressEnabled::Auto (default), progress is enabled only when stderr is a TTY

Determinate progress

use nils_term::progress::{Progress, ProgressOptions};

let total = 3_u64;
let progress = Progress::new(total, ProgressOptions::default().with_prefix("work "));

for i in 0..total {
    progress.set_message(format!("item {i}"));
    progress.inc(1);
}

progress.finish();

Spinner progress

use nils_term::progress::{Progress, ProgressFinish, ProgressOptions};

let spinner = Progress::spinner(
    ProgressOptions::default()
        .with_prefix("fetch ")
        .with_finish(ProgressFinish::Clear),
);

spinner.set_message("loading");
spinner.tick();
spinner.finish_and_clear();

Library guidance

Prefer accepting a Progress (or ProgressOptions) from the caller instead of reading env vars inside library code. This keeps libraries deterministic and lets binaries decide whether to show progress (e.g. interactive vs CI).

Migration guidance

When migrating crate-local progress code into nils-term:

1. Add/keep characterization tests before moving behavior.
2. Keep progress rendering to stderr so machine-readable stdout remains stable.
3. Keep CLI-local adapters for command wording and error/exit semantics.
4. Re-run command-contract tests for TTY, non-TTY, JSON, and NO_COLOR flows.

Docs

• Docs index