clap-rs/clap

Features

• Command-Line Argument Parsers - Defines and parses command-line interfaces into strongly-typed data structures with automatic help generation and validation.
• Argument Parsers - Captures and stores command-line inputs into structured formats for application retrieval.
• CLI Frameworks - Provides a toolkit for building complex command-line applications using attribute-based macros or programmatic builders to map inputs to code.
• CLI Argument Definitions - Configures flags, options, and positional arguments with custom names, aliases, and index positions.
• Declarative Argument Definitions - Maps command-line arguments and subcommands to strongly-typed data structures using declarative attributes.
• Command-Line Interface Development - Provides a framework for building robust command-line tools by mapping flags and subcommands to strongly-typed data structures.
• Command-Line Interface Mappings - Uses procedural macros to map struct definitions to command-line interface schemas at compile time.
• Type-Safe Schema Validations - Converts raw string inputs into strongly-typed data structures using trait-based validation.
• Shell Completion Generators - Generates shell completion scripts for various environments to improve user experience and discoverability.
• Subcommand Registration - Supports nested command hierarchies by delegating parsing to independent subcommand instances.
• Fluent Interfaces - Provides a fluent builder API for constructing complex command-line interfaces through method chaining.
• Schema-Based State Validation - Enforces complex argument relationships and validation rules through a centralized state machine during parsing.
• CLI Argument Validators - Transforms raw command-line input into typed data by applying custom parsing logic or range constraints.
• Enumerated Argument Parsers - Converts command-line input directly into typed enum variants, automatically rejecting values that do not match the set.
• Nested Command Structures - Manages nested command structures where individual subcommands maintain their own independent arguments, help documentation, and execution logic.
• Boolean Flag Generators - Automatically toggles boolean states based on the presence of command-line flags.
• Parameter Metadata Displayers - Displays help documentation and version information to the terminal when requested by the user.
• Declarative Builder Interfaces - Provides both declarative attribute-based and fluent builder-pattern APIs for defining complex command-line interfaces.
• Argument Parsing - High-performance argument parsing with extensive feature support.
• Command Line Interfaces - Full-featured command-line argument parser.
• Developer Tools - Full-featured command-line argument parser.
• Shell Integrations - Generates completions for CLI tools built with Clap.
• Environment Variable Configuration - Automatically populates command-line arguments from system environment variables.
• Variable Argument Collectors - Collects multiple instances of the same argument into lists instead of overwriting values.
• Help Generators - Allows customizing the presentation of arguments in help menus by setting descriptions, headings, and visibility for specific contexts.
• Contextual Completion Hints - Instructs command-line shells to offer context-aware suggestions for argument values to improve user experience.
• Terminal Output Formatters - Styles help documentation and error messages with colors, text wrapping, and clear diagnostic feedback for users.
• Input Behavior Configurations - Defines how the parser handles specific inputs, including custom validation, shell completion hints, and output styling.
• Compile-Time Metadata Inspection - Integrates project metadata from build configuration files during compilation to synchronize help output.
• Interface Definition Validators - Validates the integrity of the command-line interface definition during development to catch configuration errors before runtime.
• Parsing Logic Controllers - Adjusts how the parser interprets input, including hyphens, trailing values, and subcommands to support complex structures.
• Runtime Configuration Managers - Enables adjusting runtime behavior for the entire application, including terminal styling and error handling preferences.
• Positional Argument Handlers - Treats all input following a separator flag as positional arguments.
• Terminal Color Schemes - Sets preferences for terminal text color, allowing users to force, disable, or automatically detect color support.
• Error Handling - Generates, formats, and prints diagnostic messages for invalid user input, including automatic exit code management.
• Definitions - Customizes the visual presentation of help messages and error reports using configurable terminal styling definitions.
• Multi-call Execution Handlers - Supports creating single executables that change behavior based on the name used to invoke them.
• Occurrence Counters - Increments a numeric counter each time a specific flag appears to track input frequency.
• Interactive Command Line Interfaces - Supports building command-line interfaces that maintain persistent sessions for processing sequences of user inputs.
• Project Version Managers - Retrieves project version strings from configuration files for display in command-line output.
• Subcommand Existence Verifiers - Checks whether a specific command name is recognized by the application to verify input before executing logic.
• Input Suggestions - Suggests corrections for misspelled arguments and includes contextual details in error messages to help users resolve mistakes.
• Metadata Extraction Tools - Extracts application metadata from project configuration files at compile time to ensure consistency.
• Terminal Styling - Customizes the visual presentation of help menus and error messages to ensure clear, readable, and professional terminal output.

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