simple_cli

Command-Line Argument Parsing for Eiffel

v1.0.0 MIT

Overview

simple_cli provides a clean, fluent API for parsing command-line arguments in Eiffel applications. It handles flags, options with values, positional arguments, subcommands, and automatic help generation.

Part of the Simple Eiffel ecosystem.

Quick Start

Installation

  1. Set the environment variable: 
    export SIMPLE_EIFFEL=/d/prod
  2. Add to your ECF file: 
    <library name="simple_cli" location="$SIMPLE_EIFFEL/simple_cli/simple_cli.ecf"/>

Basic Usage

local
    cli: SIMPLE_CLI
do
    create cli.make
    cli.set_app_info ("myapp", "My Application", "1.0.0")

    -- Define options
    cli.add_flag ("v|verbose", "Enable verbose output")
    cli.add_option ("o|output", "Output file", "FILE")

    -- Parse and use
    cli.parse

    if cli.help_requested then
        cli.print_help
    elseif cli.has_errors then
        cli.print_errors
    else
        if cli.has_flag ("verbose") then
            print ("Verbose mode%N")
        end
    end
end

Key Features

Fluent API

Chain configuration calls for clean, readable option definitions.

Flags & Options

Boolean flags, string options, defaults, and required options.

Short & Long Names

Define both formats: "v|verbose" gives -v and --verbose.

Auto Help

Generates formatted help text from option definitions.

Typed Access

Get values as strings, integers, or booleans with defaults.

Subcommands

Git-style commands with arguments_after_command.

Examples

Subcommand Pattern

local
    cli: SIMPLE_CLI
do
    create cli.make
    cli.set_app_info ("pkg", "Package Manager", "1.0.0")
    cli.add_flag ("v|verbose", "Verbose output")
    cli.parse

    if attached cli.command as cmd then
        inspect cmd
        when "install" then
            -- pkg install package1 package2
            across cli.arguments_after_command as pkg loop
                install_package (pkg)
            end
        when "remove" then
            handle_remove (cli)
        else
            print ("Unknown command%N")
        end
    end
end

Required Options

cli.add_required_option ("i|input", "Input file", "FILE")
cli.add_required_option ("o|output", "Output file", "FILE")
cli.add_option_with_default ("f|format", "Format", "FMT", "json")
cli.parse

if cli.has_errors then
    -- "Required option missing: --input"
    cli.print_errors
end

Documentation