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docs(README.md): update examples with some comments, and fix typos
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@kbknapp
kbknapp committed Apr 9, 2015
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Expand Up @@ -27,20 +27,20 @@ After defining a list of possible valid arguments and subcommands, `clap` parses
Below are a few of the features which `clap` supports, full descriptions and usage can be found in the [documentation](http://kbknapp.github.io/clap-rs/docs/clap/index.html) and `examples/` directory

* **Auto-generated Help, Version, and Usage information**
- Can be fully, or partially overridden if you wish to roll your own help, version, or usage
- Can optionally be fully, or partially overridden if you want a custom help, version, or usage
* **Flags / Switches** (i.e. bool fields)
- Both short and long versions supported (i.e. `-f` and `--flag` respectively)
- Supports combining short versions (i.e. `-fBgoZ` is the same as `-f -B -g -o -Z`)
- Also supports multiple occurrences (i.e. `myprog -vvv` or `myprog -v -v -v`)
* **Positional Arguments** (i.e. those which are based off an index)
- Also supports multiple values (i.e. `myprog <file>...`
- Supports Specific Value Sets (See below)
- Optionally supports multiple occurrences (i.e. `myprog -vvv` or `myprog -v -v -v`)
* **Positional Arguments** (i.e. those which are based off an index from the program name)
- Optionally supports multiple values (i.e. `myprog <file>...` such as `myprog file1.txt file2.txt` being two values for the same "file" argument)
- Optionally supports Specific Value Sets (See below)
* **Option Arguments** (i.e. those that take values as options)
- Both short and long versions supported (i.e. `-o value` and `--option value` or `--option=value` respectively)
- Also supports multiple values (i.e. `myprog --option <value> --option <othervalue>`)
- Supports Specific Value Sets (See below)
- Optionally supports multiple values (i.e. `myprog --option <value> --option <other_value>`)
- Optionally supports Specific Value Sets (See below)
* **Sub-Commands** (i.e. `git add <file>` where `add` is a sub-command of `git`)
- Support their own sub-arguments, and sub-commands
- Support their own sub-arguments, and sub-commands independant of the parent
- Get their own auto-generated Help, Version, and Usage independant of parent
* **Requirement Rules**: Arguments can optionally define the following types of requirement rules
- Required by default
Expand All @@ -51,19 +51,19 @@ Below are a few of the features which `clap` supports, full descriptions and usa
- Can disallow use of other arguments when present
* **Specific Value Sets**: Positional or Option Arguments can optionally define a specific set of allowed values (i.e. imagine a `--mode` option which may *only* have one of two values `fast` or `slow` such as `--mode fast` or `--mode slow`)
* **Default Values**: Although not specifically provided by `clap` you can achieve this exact functionality from Rust's `Option<&str>.unwrap_or("some default")` method
* **Auto Version from Cargo.toml**: `clap` is fully compatible with Rust's `env!()` macro for achieving this functionality. See `examples/09_AutoVersion.rs` for how to do this (Thanks to [jhelwig](https://github.com/jhelwig) for pointing this out)
* **Get Version from Cargo.toml**: `clap` is fully compatible with Rust's `env!()` macro for automatically getting the version from your Cargo.toml. See `examples/09_AutoVersion.rs` for how to do this (Thanks to [jhelwig](https://github.com/jhelwig) for pointing this out)

## 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 [documentation](http://kbknapp.github.io/clap-rs/docs/clap/index.html) or `examples/` directory of this repository.
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.

```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")
let matches = App::new("myapp")
.version("1.0")
.author("Kevin K. <[email protected]>")
.about("Does awesome things")
Expand All @@ -72,36 +72,41 @@ fn main() {
.long("config")
.help("Sets a custom config file")
.takes_value(true))
.arg(Arg::new("output")
.help("Sets an optional output file")
.arg(Arg::new("INPUT")
.help("Sets the input file to use")
.required(true)
.index(1))
.arg(Arg::new("debug")
.short("d")
.multiple(true)
.help("Turn debugging information on"))
.subcommand(SubCommand::new("test")
.about("controls testing features")
.version("1.3")
.author("Someone E. <[email protected]>")
.arg(Arg::new("verbose")
.short("v")
.help("print test information verbosely")))
.get_matches();

if let Some(o) = matches.value_of("output") {
println!("Value for output: {}", o);
}

if let Some(c) = matches.value_of("CONFIG") {
println!("Value for config: {}", c);
}

// 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(ref matches) = matches.subcommand_matches("test") {
if let Some(matches) = matches.subcommand_matches("test") {
if matches.is_present("verbose") {
println!("Printing verbosely...");
} else {
Expand All @@ -113,33 +118,35 @@ 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 output woud be presented
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

```sh
$ myprog --help
MyApp 1.0
$ myapp --help
myapp 1.0
Kevin K. <[email protected]>
Does awesome things

USAGE:
MyApp [FLAGS] [OPTIONS] [POSITIONAL] [SUBCOMMANDS]
MyApp [FLAGS] [OPTIONS] <INPUT> [SUBCOMMANDS]

FLAGS:
-d Turn debugging information on
-h,--help Prints this message
-v,--version Prints version information
-h, --help Prints this message
-v, --version Prints version information

OPTIONS:
-c,--config=CONFIG Sets a custom config file
-c, --config=CONFIG Sets a custom config file

POSITIONAL ARGUMENTS:
output Sets an optional output file
INPUT The input file to use

SUBCOMMANDS:
help Prints this message
test Controls testing features
help Prints this message
test Controls testing features
```

*NOTE:* You could also run `myapp test --help` to see similar output and options for the `test` subcommand.

## Installation

Add `clap` as a dependecy in your `Cargo.toml` file to use from crates.io:
Expand All @@ -157,33 +164,33 @@ git = "https://github.com/kbknapp/clap-rs.git"

Add `extern crate clap;` to your crate root.

Define a list of valid arguments for your program (see the documentation or examples/ directory)
Define a list of valid arguments for your program (see the [documentation](https://kbknapp.github.io/clap-rs/index.html) or `examples/` directory of this repo)

Then run `cargo build` or `cargo update && cargo build` for your project.

### More Information

You can find complete documentation on the [github-pages site](http://kbknapp.github.io/clap-rs/docs/clap/index.html) for this project.

You can also find full usage examples in the `examples/` directory of this repo.
You can also find usage examples in the `examples/` directory of this repo.

## How to build and contribute
## How to Contribute

Contributions are always welcome! And there is a multitude of ways in which you can help depending on what you like to do, or are good at. Anything from documentation, code cleanup, issue completion, new features, you name it, even filing issues is contributing and greatly appreciated!

1. Fork the project
2. Clone your fork (`git clone https://github.com/$USER/clap-rs && cd clap-rs`)
3. Create new branch (`git checkout -b your-branch`)
4. Make your changes, and commit (`git commit -am "your message"`) (I try to use a [conventional](https://github.com/ajoslin/conventional-changelog/blob/master/CONVENTIONS.md) changelog format using [clog](https://github.com/thoughtram/clog))
2. Clone your fork (`git clone https://github.com/$YOUR_USERNAME/clap-rs && cd clap-rs`)
3. Create new branch (`git checkout -b new-branch`)
4. Make your changes, and commit (`git commit -am "your message"`) (I try to use a [conventional](https://github.com/ajoslin/conventional-changelog/blob/master/CONVENTIONS.md) changelog format so I can update it using [clog](https://github.com/thoughtram/clog))
5. If applicable, run the tests (See below)
6. Push your changes back to your fork (`git push origin your-branch`)
7. Create a pull request! (You can create the pull request right away, and we'll merge when read. This a good way to discuss proposed changes)
7. Create a pull request! (You can also create the pull request right away, and we'll merge when ready. This a good way to discuss proposed changes.)

Another really great way to help is if you find an interesting, or helpful way in which to use `clap` you can either add it to the `examples/` directory, or file an issue and tell me. I'm all about giving credit where credit is due :)
Another really great way to help is if you find an interesting, or helpful way in which to use `clap`. You can either add it to the `examples/` directory, or file an issue and tell me. I'm all about giving credit where credit is due :)

### Running the tests

If contributing, you can run the tests as follows (assuming you've already cloned the repo to `clap-rs/`
If contributing, you can run the tests as follows (assuming you've cloned the repo to `clap-rs/`

```
cd clap-rs && cargo test
Expand All @@ -192,28 +199,28 @@ cd clap-tests && make test

### Building the documentation

If the changes require re-building the documentation, run this instead of `cargo doc` to generate the proper module docstring:
If your changes require re-building the documentation, run this instead of `cargo doc` to generate the proper module docstring:

```
make doc
cd clap-rs && make doc
```

Then browse to `clap-rs/docs/clap/index.html` in your web-browser of choice to check it out. You can then create a PR on the `gh-pages` branch
Then browse to `clap-rs/docs/clap/index.html` in your web-browser of choice to check it out.

### Goals

There are a few goals of `clap` that I'd like to maintain. If your proposed changes break, or go against any of these goals we'll discuss the changes further before merging (but will *not* be ignored, all contributes are welcome!). These are by no means hard-and-fast rules, as I'm no expert and break them myself from time to time (even if just by mistake or ignorance :P).
There are a few goals of `clap` that I'd like to maintain throughout contributions. If your proposed changes break, or go against any of these goals we'll discuss the changes further before merging (but will *not* be ignored, all contributes are welcome!). These are by no means hard-and-fast rules, as I'm no expert and break them myself from time to time (even if by mistake or ignorance :P).

* Remain backwards compatible when possible
- If backwards compatibility *must* be broken, use deprecation warnings if at all possible before removing legacy code
- This does not apply for security concerns
* Parse arguments quickly
- Parsing of arguments shouldn't slow down usage of the main program
- This is also true of generating help and usage information
- This is also true of generating help and usage information (although *slightly* less stringent, as the program is about to exit)
* Try to be cognizant of memory usage
- Once parsing is complete, the memory footprint of `clap` should be low since the main program is the star of the show
* `panic!` on *developer* error, exit gracefully on *end-user* error

## License

`clap` is licensed under the MIT license. Please the LICENSE file in this repository for more information.
`clap` is licensed under the MIT license. Please the LICENSE-MIT file in this repository for more information.

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