cliss 1.1.0

A lightweight framework for building CLI applications on top of sys.argv

cliss — A lightweight framework for building CLI applications

Write type-annotated Python functions, get a full CLI — automatic --help, validation, async support, and zero dependencies.

✨ Features

• Zero Dependencies — Pure stdlib: sys, asyncio, inspect
• Type-Driven — Automatic arguments from function signatures and type hints
• Flexible — Declarative Argument objects, type inference, or both
• Async-Native — async def handlers with automatic event loop management
• Global Args — Define flags shared across all commands
• Coloured Help — Beautiful terminal output via ANSI-codes (can be disabled)
• Bool Flags — Automatic --name/--no-name mutually exclusive group
• Manual Parsing — Pure sys.argv parsing, no argparse dependency

🚀 Quick Start

Installation

pip install cliss

Usage

from cliss import CLI

cli = CLI(name="todo", description="Task manager", version="1.0.0")

@cli.command()
def add(task: str, priority: int = 1, done: bool = False):
    """Add a task."""
    status = "✓" if done else "○"
    return f"[{status}] {task} (priority: {priority})"

cli.run()

$ python todo.py add "Buy milk" --priority 2
[○] Buy milk (priority: 2)

$ python todo.py add "Call mom" --done
[✓] Call mom (priority: 1)

$ python todo.py add "Test" --no-done
[○] Test (priority: 1)

Disable Colours

# No colours in output
cli = CLI(name="myapp", colour=False)

# Or via environment variable
$ NO_COLOR=1 python myapp.py --help

📋 API Reference

CLI class

CLI(
    name="cli",
    description=None,
    version=None,
    colour=True,
)

Parameter	Type	Default	Description
name	str	None	Program name in help
description	str	None	Description in help
version	str	None	Adds --version flag
usage	str	"{self.name} [COMMAND] [OPTIONS] [ARGS]..."	Custom usage string
colour	bool	True	Enable/disable ANSI colours in output

Argument class

from cliss import Argument

Argument("--output", "-o", type=str, default=None, help="...", choices=["json","csv"], action="store_true")

Parameter	Type	Default	Description
*flags	str	—	Argument flags
type	type	str	Value type
default	Any	None	Default value
help	str	""	Help text
required	bool	False	Make required
choices	list	None	Allowed values
action	str	None	argparse action

Type → CLI Mapping

Function Signature	CLI Argument
name: str	Positional name
count: int = 1	--count (default: 1)
verbose: bool = False	--verbose/--no-verbose
mode: str = None	--mode (default: None)

📖 Examples

CRUD Application

from cliss import CLI

cli = CLI(name="db")
db = {}

@cli.command()
def set(key: str, value: str):
    db[key] = value
    return f"OK: {key} = {value}"

@cli.command()
def get(key: str):
    return db.get(key, "Not found")

@cli.command()
def delete(key: str, force: bool = False):
    if force or key in db:
        db.pop(key, None)
        return f"Deleted: {key}"
    return f"Not found (use --force)"

cli.run()

Command Groups

cli = CLI(name="git")

remote = cli.group("remote", "Manage remotes")
stash = cli.group("stash", "Stash changes")

@remote.command()
def add(name: str, url: str):
    return f"Added remote {name}"

@stash.command()
def push(message: str = ""):
    return f"Stashed: {message or 'WIP'}"

cli.run()

Async Commands

@cli.command()
async def fetch(url: str, retries: int = 3):
    return f"Fetched {url} (retries: {retries})"

❓ FAQ

Why cliss over argparse/Click/Typer/Fire?

Tool	Deps	Style	Parser
cliss	0	Decorators + type hints	sys.argv
Fire	1 (termcolor)	Introspection	Custom
Click	0	Decorators	Custom
Typer (0.26.0+)	0	Type hints	click

cliss = Fire's zero-bloat philosophy + Typer's type-driven design. Pure sys.argv parsing, custom help formatter with ANSI-colours.

Why sys.argv instead of argparse?

Manual sys.argv parsing gives complete control over argument handling, removes dependency on argparse internals, and keeps the codebase minimal. The custom parser handles flags, positional arguments, bool pairs, and type coercion directly.

Bool flags?

Automatic --name/--no-name mutually exclusive group. store_true by default, store_false if default is True.

Async?

async def handlers auto-run with asyncio.run(). Sync functions returning coroutines also work. Disable with simple=True for pure sync scripts.

Help customisation?

Full Cargo-style coloured help with HelpTheme configuration. Custom usage strings, examples sections, and per-command help registration via Help.register_command_help(). Disable colours with colour=False or NO_COLOR environment variable.

📄 License

MIT — see LICENSE file.

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Author: Fkernel653 Repository: github.com/Fkernel653/cliss PyPI: pypi.org/project/cliss