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Break out the printing of usage to stdout into its own function #27

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Break out the printing of usage to stdout into its own function #27

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54 changes: 32 additions & 22 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -163,6 +163,7 @@

pub use gumdrop_derive::*;

use std::env::args;
use std::error::Error as StdError;
use std::fmt;
use std::slice::Iter;
Expand Down Expand Up @@ -530,6 +531,36 @@ pub trait Options: Sized {
Self::parse(&mut Parser::new(args, style))
}

/// Just print the usage to stdout based on parsed Options.
///
/// Useful for printing the same --help or default no-args output
/// for multiple cases.
fn print_usage(opts: Self) {
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@murarth murarth Jan 7, 2020

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Is there any reason this can't be &self?

let args = args().collect::<Vec<_>>();

match opts.command_name() {
None => {
println!("Usage: {} [OPTIONS]", args[0]);
println!();
println!("{}", Self::usage());

if let Some(cmds) = Self::command_list() {
println!();
println!("Available commands:");
println!();
println!("{}", cmds);
}
}
Some(cmd) => {
let help = Self::command_usage(cmd).unwrap_or_default();

println!("Usage: {} {} [OPTIONS]", args[0], cmd);
println!();
println!("{}", help);
}
}
}

/// Parses arguments from the environment.
///
/// If an error is encountered, the error is printed to `stderr` and the
Expand All @@ -540,7 +571,6 @@ pub trait Options: Sized {
///
/// Otherwise, the parsed options are returned.
fn parse_args_or_exit(style: ParsingStyle) -> Self {
use std::env::args;
use std::process::exit;

let args = args().collect::<Vec<_>>();
Expand All @@ -551,27 +581,7 @@ pub trait Options: Sized {
});

if opts.help_requested() {
match opts.command_name() {
None => {
println!("Usage: {} [OPTIONS]", args[0]);
println!();
println!("{}", Self::usage());

if let Some(cmds) = Self::command_list() {
println!();
println!("Available commands:");
println!();
println!("{}", cmds);
}
}
Some(cmd) => {
let help = Self::command_usage(cmd).unwrap_or_default();

println!("Usage: {} {} [OPTIONS]", args[0], cmd);
println!();
println!("{}", help);
}
}
Self::print_usage(opts);
exit(0);
}

Expand Down