click-compose

Composable Click callback utilities for building flexible CLI applications.

• Installation
• Quick Start
  • multi_callback
  • sequence_validator
  • deduplicate
• Documentation

Installation

$ pip install click-compose

Or with uv:

$ uv add click-compose

Quick Start

click-compose provides utilities for composing Click callbacks:

multi_callback

Combine multiple callbacks into a single callback that applies them in sequence:

"""Example of using multi_callback to combine validators."""

import click

from click_compose import multi_callback


def validate_positive(
    _ctx: click.Context,
    _param: click.Parameter,
    value: int,
) -> int:
    """Validate that value is positive."""
    if value <= 0:
        msg = "Must be positive"
        raise click.BadParameter(message=msg)
    return value


MAX_VALUE = 100


def validate_max_100(
    _ctx: click.Context,
    _param: click.Parameter,
    value: int,
) -> int:
    """Validate that value is at most 100."""
    if value > MAX_VALUE:
        msg = "Must be <= 100"
        raise click.BadParameter(message=msg)
    return value


@click.command()
@click.option(
    "--count",
    type=int,
    callback=multi_callback(callbacks=[validate_positive, validate_max_100]),
)
def cmd(count: int) -> None:
    """Example command with multiple validators."""
    click.echo(message=f"Count: {count}")

sequence_validator

Apply a validator to each element in a sequence (useful with multiple=True):

"""Example of using sequence_validator with multiple values."""

import click

from click_compose import sequence_validator


def validate_positive(
    _ctx: click.Context | None,
    _param: click.Parameter | None,
    value: int,
) -> int:
    """Validate that value is positive."""
    if value <= 0:
        msg = "Must be positive"
        raise click.BadParameter(message=msg)
    return value


@click.command()
@click.option(
    "--numbers",
    multiple=True,
    type=int,
    callback=sequence_validator(validator=validate_positive),
)
def cmd(numbers: tuple[int, ...]) -> None:
    """Example command with sequence validation."""
    click.echo(message=f"Sum: {sum(numbers)}")

deduplicate

Remove duplicates from a sequence while preserving order (useful with multiple=True):

"""Example of using ``deduplicate`` to remove duplicate values."""

import click

from click_compose import deduplicate


@click.command()
@click.option(
    "--tags",
    multiple=True,
    type=str,
    callback=deduplicate,
)
def cmd(tags: tuple[str, ...]) -> None:
    """Example command that removes duplicate tags."""
    click.echo(message=f"Unique tags: {', '.join(tags)}")

Documentation

See the full documentation.