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docs(README.md): update readme examples with new from_usage() methods

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Kevin K. 2015-04-13 14:19:56 -04:00
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README.md
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@ -10,6 +10,8 @@ It is a simple to use and efficient library for parsing command line arguments a
I've been working on a few short video tutorials about using `clap`. They're located on [youtube](https://www.youtube.com/playlist?list=PLza5oFLQGTl0Bc_EU_pBNcX-rhVqDTRxv).
*Note*: The videos have not been updated to include the new `from_usage()` methods which make building args significantly less verbose. New videos will be added soon.
*Note*: Apologies for the resolution of the first video, it will be updated to a better resolution soon. The other videos have a proper resolution.
## About
@ -55,7 +57,58 @@ Below are a few of the features which `clap` supports, full descriptions and usa
## Quick Example
The following shows a quick example of some of the basic functionality of `clap`. For more advanced usage, such as requirements, exclusions, multiple values and occurrences see the [video tutorials](https://www.youtube.com/playlist?list=PLza5oFLQGTl0Bc_EU_pBNcX-rhVqDTRxv), [documentation](http://kbknapp.github.io/clap-rs/docs/clap/index.html), or `examples/` directory of this repository.
The following two examples (which are functionally equivilant, but show two different ways to use `clap`) show a quick example of some of the basic functionality of `clap`. For more advanced usage, such as requirements, exclusions, multiple values and occurrences see the [video tutorials](https://www.youtube.com/playlist?list=PLza5oFLQGTl0Bc_EU_pBNcX-rhVqDTRxv), [documentation](http://kbknapp.github.io/clap-rs/docs/clap/index.html), or `examples/` directory of this repository.
```rust
// (Full example with comments in examples/01_QuickExample.rs)
extern crate clap;
use clap::{Arg, App, SubCommand};
fn main() {
let matches = App::new("myapp")
.version("1.0")
.author("Kevin K. <kbknapp@gmail.com>")
.about("Does awesome things")
.args_from_usage(
"-c --config=[CONFIG] 'Sets a custom config file'
<INPUT> 'Sets the input file to use'
[debug]... -d 'Sets the level of debugging information'")
.subcommand(SubCommand::new("test")
.about("controls testing features")
.version("1.3")
.author("Someone E. <someone_else@other.com>")
.arg_from_usage("-v --verbose 'Print test information verbosely'"))
.get_matches();
// Calling .unwrap() is safe here because "INPUT" is required (if "INPUT" wasn't
// required we could have used an 'if let' to conditionally get the value)
println!("Using input file: {}", matches.value_of("INPUT").unwrap());
// Gets a value for config if supplied by user, or defaults to "default.conf"
let config = matches.value_of("CONFIG").unwrap_or("default.conf");
println!("Value for config: {}", config);
// Vary the output based on how many times the user used the "debug" flag
// (i.e. 'myapp -d -d -d' or 'myapp -ddd' vs 'myapp -d'
match matches.occurrences_of("debug") {
0 => println!("Debug mode is off"),
1 => println!("Debug mode is kind of on"),
2 => println!("Debug mode is on"),
3 | _ => println!("Don't be crazy"),
}
if let Some(matches) = matches.subcommand_matches("test") {
if matches.is_present("verbose") {
println!("Printing verbosely...");
} else {
println!("Printing normally...");
}
}
// more porgram logic goes here...
}
```
While functionally the following example is functionally the same as above, this method allows more advanced configuration options, or even dynamically generating arguments when desired.
```rust
// (Full example with comments in examples/01_QuickExample.rs)
@ -79,7 +132,7 @@ fn main() {
.arg(Arg::new("debug")
.short("d")
.multiple(true)
.help("Turn debugging information on"))
.help("Sets the level of debugging information"))
.subcommand(SubCommand::new("test")
.about("controls testing features")
.version("1.3")
@ -118,7 +171,7 @@ fn main() {
}
```
If you were to compile the above program and run it with the flag `--help` or `-h` (or `help` subcommand, since we defined `test` as a subcommand) the following would be output
If you were to compile either of the above programs and run them with the flag `--help` or `-h` (or `help` subcommand, since we defined `test` as a subcommand) the following would be output
```sh
$ myapp --help