Struct ArgParser 

pub struct ArgParser { /* private fields */ }

The argument parser. Holds the schema (flags, options, positionals, subcommands) and provides methods to parse arguments, generate help text, and serialize/deserialize the schema.

Constructed via ArgBuilder::build().

Implementations

impl ArgParser

pub fn generate_completions(&self, shell: Shell) -> String

Generate a shell completion script for the given shell.

Returns a self-contained script string that, when sourced or installed, provides tab-completion for your CLI’s flags, options, and subcommands.

Shell-specific behaviour

Shell	Descriptions	Short/long exclusion	Script format
Bash	No	No	complete -F function
Zsh	Yes	Yes	#compdef + _arguments
Fish	Yes	No	complete -c commands
PowerShell	Yes	No	Register-ArgumentCompleter

Example

use nanoargs::{ArgBuilder, Flag, Shell};

let parser = ArgBuilder::new()
    .name("myapp")
    .flag(Flag::new("verbose").short('v').desc("Enable verbose output"))
    .build()
    .unwrap();

let script = parser.generate_completions(Shell::Bash);
assert!(script.contains("complete -F"));

impl ArgParser

pub fn help_text(&self) -> String

Generate formatted help text for this parser.

Includes the description, usage line, options, positional arguments, and subcommands sections. When the color feature is enabled and the terminal supports it, the output includes ANSI color codes.

impl ArgParser

pub fn program_name(&self) -> Option<&str>

Returns the program name, if set.

pub fn program_desc(&self) -> Option<&str>

Returns the program description, if set.

pub fn flags(&self) -> &[FlagDef]

Returns the registered flag definitions.

pub fn options(&self) -> &[OptionDef]

Returns the registered option definitions.

pub fn positionals(&self) -> &[PositionalDef]

Returns the registered positional definitions.

pub fn subcommands(&self) -> &[SubcommandDef]

Returns the registered subcommand definitions.

pub fn version_text(&self) -> Option<String>

Returns formatted version text, or None if no version is configured.

pub fn parse(&self, args: Vec<String>) -> Result<ParseResult, ParseError>

Parse a list of argument strings.

Returns Err(ParseError::HelpRequested(_)) or Err(ParseError::VersionRequested(_)) when -h/--help or -V/--version are encountered — these are not errors per se, but signal that the caller should print the contained text and exit.

pub fn parse_env(&self) -> Result<ParseResult, ParseError>

Parse arguments directly from std::env::args(), skipping the program name (argv[0]).

This is the recommended entry point for real CLI applications. Returns Err(ParseError::InvalidUtf8(_)) if any argument contains bytes that are not valid UTF-8.

Trait Implementations

impl Clone for ArgParser

fn clone(&self) -> ArgParser

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ArgParser

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for ArgParser

fn eq(&self, other: &ArgParser) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for ArgParser