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docs(Examples): adds better usage examples instead of having unused variables

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This commit is contained in:
Kevin K 2015-08-30 16:16:35 -04:00
parent 4f836ee5ef
commit 8cbacd8883
6 changed files with 48 additions and 22 deletions
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11
examples/02_apps.rs
View file

@ -2,7 +2,6 @@ extern crate clap;
use clap::{App};
#[allow(unused_variables)]
fn main() {
// Apps describe the top level application
//
@ -19,11 +18,11 @@ fn main() {
// Once all options have been set, call .get_matches() in order to start the parsing and find all valid
// command line arguments that supplied by the user at runtime. The name given to new() will be displayed
// when the version or help flags are used.
let matches = App::new("MyApp")
.version("1.0")
.author("Kevin K. <kbknapp@gmail.com>")
.about("Does awesome things")
.get_matches();
App::new("MyApp")
.version("1.0")
.author("Kevin K. <kbknapp@gmail.com>")
.about("Does awesome things")
.get_matches();
// This example doesn't do much, but it *does* give automatic -h, --help, -V, and --version functionality ;)

23
examples/03_args.rs
View file

@ -2,7 +2,6 @@ extern crate clap;
use clap::{App, Arg};
#[allow(unused_variables)]
fn main() {
// Args describe a possible valid argument which may be supplied by the user at runtime. There
// are three different types of arguments (flags, options, and positional) as well as a fourth
@ -39,6 +38,7 @@ fn main() {
.args( vec![
Arg::with_name("config")
.help("sets the config file to use")
.takes_value(true)
.short("c")
.long("config"),
Arg::with_name("input")
@ -61,5 +61,24 @@ fn main() {
-i --int=[interface] 'Set an interface to use'")
.get_matches();
// Continued program logic goes here...
// Here are some examples of using the arguments defined above. Keep in mind that this is only
// an example, and may be somewhat contrived
//
// First we check if debugging should be on or not
println!("Debugging mode is: {}", if matches.is_present("debug") { "ON" } else { "OFF" });
// Next we print the config file we're using, if any was defined with either -c <file> or
// --config <file>
if let Some(config) = matches.value_of("config") {
println!("A config file was passed in: {}", config);
}
// Let's print the <INPUT> file the user passed in. We can use .unwrap() here becase the arg is
// required, and parsing would have failed if the user forgot it
println!("Using input file: {}", matches.value_of("input").unwrap());
// We could continue checking for and using arguments in this manner, such as "license",
// "output", and "interface". Keep in mind that "output" and "interface" are optional, so you
// shouldn't call .unwrap(), instead prefer using an 'if let' expression as we did with
// "config"
}

11
examples/09_auto_version.rs
View file

@ -3,7 +3,6 @@ extern crate clap;
use clap::App;
#[allow(unused_variables)]
fn main() {
// You can have clap pull the application version directly from your Cargo.toml starting with
// clap v0.4.14 on crates.io (or master#a81f915 on github). Using Rust's env! macro like this:
@ -19,11 +18,11 @@ fn main() {
// the version.
//
// Thanks to https://github.com/jhelwig for pointing this out
let matches = App::new("myapp")
.about("does awesome things")
// use crate_version! to pull the version number
.version(&crate_version!()[..])
.get_matches();
App::new("myapp")
.about("does awesome things")
// use crate_version! to pull the version number
.version(&crate_version!()[..])
.get_matches();
// running the this app with the -V or --version will display whatever version is in your
// Cargo.toml, the default being: myapp 0.0.1

4
examples/10_default_values.rs
View file

@ -2,7 +2,6 @@ extern crate clap;
use clap::{App, Arg};
#[allow(unused_variables)]
fn main() {
// You can get a "default value" like feature by using Option<T>'s .unwrap_or() method
//
@ -17,5 +16,6 @@ fn main() {
let config_file = matches.value_of("CONFIG").unwrap_or("config.json");
// use config_file here...
// If the user passed in a -c <file> we'll see that value, if not we'll see 'config.json'
println!("The config file is: {}", config_file);
}

4
examples/15_custom_validator.rs
View file

@ -2,7 +2,6 @@ extern crate clap;
use clap::{App, Arg};
#[allow(unused_variables)]
fn main() {
// You can define a function (or a closure) to use as a validator to argument values. The
// function must accept a String and return Result<(), String> where Err(String) is the message
@ -33,5 +32,6 @@ fn main() {
}))
.get_matches();
// Continued program logic here...
// Here we can call .unwrap() because the argument is required.
println!("The .PNG file is: {}", matches.value_of("input").unwrap());
}

17
examples/16_app_settings.rs
View file

@ -2,7 +2,6 @@ extern crate clap;
use clap::{App, AppSettings, SubCommand};
#[allow(unused_variables)]
fn main() {
// You can use AppSettings to change the application level behavior of clap. .setting() function
// of App struct takes AppSettings enum as argument. There is also .settings() function which
@ -20,13 +19,23 @@ fn main() {
// Required positional argument called input. This
// will be only required if subcommand is not present.
.subcommand(SubCommand::with_name("help")
.about("shows help message"))
.subcommand(SubCommand::with_name("test")
.about("does some testing"))
// if program is invoked with subcommand, you do not
// need to specify the <input> argument anymore due to
// the AppSettings::SubcommandsNegateReqs setting.
.get_matches();
// Contiued program logic goes here...
// Calling unwrap() on "input" would not be advised here, because although it's required,
// if the user uses a subcommand, those requirements are no longer required. Hence, we should
// use some sort of 'if let' construct
if let Some(inp) = matches.value_of("input") {
println!("The input file is: {}", inp);
}
match matches.subcommand() {
("test", _) => println!("The 'test' subcommand was used"),
_ => unreachable!()
}
}