1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
// Copyright ⓒ 2015-2016 Kevin B. Knapp and [`clap-rs` contributors](https://github.com/clap-rs/clap/blob/master/CONTRIBUTORS.md).
// Licensed under the MIT license
// (see LICENSE or <http://opensource.org/licenses/MIT>) All files in the project carrying such
// notice may not be copied, modified, or distributed except according to those terms.

//! `clap` is a simple-to-use, efficient, and full-featured library for parsing command line
//! arguments and subcommands when writing console/terminal applications.
//!
//! ## About
//!
//! `clap` is used to parse *and validate* the string of command line arguments provided by the user
//! at runtime. You provide the list of valid possibilities, and `clap` handles the rest. This means
//! you focus on your *applications* functionality, and less on the parsing and validating of
//! arguments.
//!
//! `clap` also provides the traditional version and help switches (or flags) 'for free' meaning
//! automatically with no configuration. It does this by checking the list of valid possibilities you
//! supplied and adding only the ones you haven't already defined. If you are using subcommands,
//! `clap` will also auto-generate a `help` subcommand for you in addition to the traditional flags.
//!
//! Once `clap` parses the user provided string of arguments, it returns the matches along with any
//! applicable values. If the user made an error or typo, `clap` informs them of the mistake and
//! exits gracefully (or returns a `Result` type and allows you to perform any clean up prior to
//! exit). Because of this, you can make reasonable assumptions in your code about the validity of
//! the arguments.
//!
//!
//! ## Quick Example
//!
//! The following examples show a quick example of some of the very basic functionality of `clap`.
//! For more advanced usage, such as requirements, conflicts, groups, multiple values and
//! occurrences see the [documentation](https://docs.rs/clap/), [examples/] directory of
//! this repository or the [video tutorials].
//!
//! **NOTE:** All of these examples are functionally the same, but show different styles in which to
//! use `clap`
//!
//! The first example shows a method that allows more advanced configuration options (not shown in
//! this small example), or even dynamically generating arguments when desired. The downside is it's
//! more verbose.
//!
//! ```no_run
//! // (Full example with detailed comments in examples/01b_quick_example.rs)
//! //
//! // This example demonstrates clap's full 'builder pattern' style of creating arguments which is
//! // more verbose, but allows easier editing, and at times more advanced options, or the possibility
//! // to generate arguments dynamically.
//! extern crate clap;
//! use clap::{Arg, App, SubCommand};
//!
//! fn main() {
//!     let matches = App::new("My Super Program")
//!                           .version("1.0")
//!                           .author("Kevin K. <kbknapp@gmail.com>")
//!                           .about("Does awesome things")
//!                           .arg(Arg::with_name("config")
//!                                .short("c")
//!                                .long("config")
//!                                .value_name("FILE")
//!                                .help("Sets a custom config file")
//!                                .takes_value(true))
//!                           .arg(Arg::with_name("INPUT")
//!                                .help("Sets the input file to use")
//!                                .required(true)
//!                                .index(1))
//!                           .arg(Arg::with_name("v")
//!                                .short("v")
//!                                .multiple(true)
//!                                .help("Sets the level of verbosity"))
//!                           .subcommand(SubCommand::with_name("test")
//!                                       .about("controls testing features")
//!                                       .version("1.3")
//!                                       .author("Someone E. <someone_else@other.com>")
//!                                       .arg(Arg::with_name("debug")
//!                                           .short("d")
//!                                           .help("print debug information verbosely")))
//!                           .get_matches();
//!
//!     // 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);
//!
//!     // 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());
//!
//!     // Vary the output based on how many times the user used the "verbose" flag
//!     // (i.e. 'myprog -v -v -v' or 'myprog -vvv' vs 'myprog -v'
//!     match matches.occurrences_of("v") {
//!         0 => println!("No verbose info"),
//!         1 => println!("Some verbose info"),
//!         2 => println!("Tons of verbose info"),
//!         3 | _ => println!("Don't be crazy"),
//!     }
//!
//!     // You can handle information about subcommands by requesting their matches by name
//!     // (as below), requesting just the name used, or both at the same time
//!     if let Some(matches) = matches.subcommand_matches("test") {
//!         if matches.is_present("debug") {
//!             println!("Printing debug info...");
//!         } else {
//!             println!("Printing normally...");
//!         }
//!     }
//!
//!     // more program logic goes here...
//! }
//! ```
//!
//! The next example shows a far less verbose method, but sacrifices some of the advanced
//! configuration options (not shown in this small example). This method also takes a *very* minor
//! runtime penalty.
//!
//! ```no_run
//! // (Full example with detailed comments in examples/01a_quick_example.rs)
//! //
//! // This example demonstrates clap's "usage strings" method of creating arguments
//! // which is less verbose
//! 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=[FILE] 'Sets a custom config file'
//!                               <INPUT>              'Sets the input file to use'
//!                               -v...                'Sets the level of verbosity'")
//!                           .subcommand(SubCommand::with_name("test")
//!                                       .about("controls testing features")
//!                                       .version("1.3")
//!                                       .author("Someone E. <someone_else@other.com>")
//!                                       .arg_from_usage("-d, --debug 'Print debug information'"))
//!                           .get_matches();
//!
//!     // Same as previous example...
//! }
//! ```
//!
//! This third method shows how you can use a YAML file to build your CLI and keep your Rust source
//! tidy or support multiple localized translations by having different YAML files for each
//! localization.
//!
//! First, create the `cli.yml` file to hold your CLI options, but it could be called anything we
//! like:
//!
//! ```yaml
//! name: myapp
//! version: "1.0"
//! author: Kevin K. <kbknapp@gmail.com>
//! about: Does awesome things
//! args:
//!     - config:
//!         short: c
//!         long: config
//!         value_name: FILE
//!         help: Sets a custom config file
//!         takes_value: true
//!     - INPUT:
//!         help: Sets the input file to use
//!         required: true
//!         index: 1
//!     - verbose:
//!         short: v
//!         multiple: true
//!         help: Sets the level of verbosity
//! subcommands:
//!     - test:
//!         about: controls testing features
//!         version: "1.3"
//!         author: Someone E. <someone_else@other.com>
//!         args:
//!             - debug:
//!                 short: d
//!                 help: print debug information
//! ```
//!
//! Since this feature requires additional dependencies that not everyone may want, it is *not*
//! compiled in by default and we need to enable a feature flag in Cargo.toml:
//!
//! Simply change your `clap = "~2.27.0"` to `clap = {version = "~2.27.0", features = ["yaml"]}`.
//!
//! At last we create our `main.rs` file just like we would have with the previous two examples:
//!
//! ```ignore
//! // (Full example with detailed comments in examples/17_yaml.rs)
//! //
//! // This example demonstrates clap's building from YAML style of creating arguments which is far
//! // more clean, but takes a very small performance hit compared to the other two methods.
//! #[macro_use]
//! extern crate clap;
//! use clap::App;
//!
//! fn main() {
//!     // The YAML file is found relative to the current file, similar to how modules are found
//!     let yaml = load_yaml!("cli.yml");
//!     let matches = App::from_yaml(yaml).get_matches();
//!
//!     // Same as previous examples...
//! }
//! ```
//!
//! Finally there is a macro version, which is like a hybrid approach offering the speed of the
//! builder pattern (the first example), but without all the verbosity.
//!
//! ```no_run
//! #[macro_use]
//! extern crate clap;
//!
//! fn main() {
//!     let matches = clap_app!(myapp =>
//!         (version: "1.0")
//!         (author: "Kevin K. <kbknapp@gmail.com>")
//!         (about: "Does awesome things")
//!         (@arg CONFIG: -c --config +takes_value "Sets a custom config file")
//!         (@arg INPUT: +required "Sets the input file to use")
//!         (@arg debug: -d ... "Sets the level of debugging information")
//!         (@subcommand test =>
//!             (about: "controls testing features")
//!             (version: "1.3")
//!             (author: "Someone E. <someone_else@other.com>")
//!             (@arg verbose: -v --verbose "Print test information verbosely")
//!         )
//!     ).get_matches();
//!
//!     // Same as before...
//! }
//! ```
//!
//! If you were to compile any 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
//!
//! ```text
//! $ myprog --help
//! My Super Program 1.0
//! Kevin K. <kbknapp@gmail.com>
//! Does awesome things
//!
//! USAGE:
//!     MyApp [FLAGS] [OPTIONS] <INPUT> [SUBCOMMAND]
//!
//! FLAGS:
//!     -h, --help       Prints this message
//!     -v               Sets the level of verbosity
//!     -V, --version    Prints version information
//!
//! OPTIONS:
//!     -c, --config <FILE>    Sets a custom config file
//!
//! ARGS:
//!     INPUT    The input file to use
//!
//! SUBCOMMANDS:
//!     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.
//!
//! ## Try it!
//!
//! ### Pre-Built Test
//!
//! To try out the pre-built example, use the following steps:
//!
//! * Clone the repository `$ git clone https://github.com/clap-rs/clap && cd clap-rs/tests`
//! * Compile the example `$ cargo build --release`
//! * Run the help info `$ ./target/release/claptests --help`
//! * Play with the arguments!
//!
//! ### BYOB (Build Your Own Binary)
//!
//! To test out `clap`'s default auto-generated help/version follow these steps:
//!
//! * Create a new cargo project `$ cargo new fake --bin && cd fake`
//! * Add `clap` to your `Cargo.toml`
//!
//! ```toml
//! [dependencies]
//! clap = "2"
//! ```
//!
//! * Add the following to your `src/main.rs`
//!
//! ```no_run
//! extern crate clap;
//! use clap::App;
//!
//! fn main() {
//!   App::new("fake").version("v1.0-beta").get_matches();
//! }
//! ```
//!
//! * Build your program `$ cargo build --release`
//! * Run with help or version `$ ./target/release/fake --help` or `$ ./target/release/fake
//! --version`
//!
//! ## Usage
//!
//! For full usage, add `clap` as a dependency in your `Cargo.toml` (it is **highly** recommended to
//! use the `~major.minor.patch` style versions in your `Cargo.toml`, for more information see
//! [Compatibility Policy](#compatibility-policy)) to use from crates.io:
//!
//! ```toml
//! [dependencies]
//! clap = "~2.27.0"
//! ```
//!
//! Or get the latest changes from the master branch at github:
//!
//! ```toml
//! [dependencies.clap]
//! git = "https://github.com/clap-rs/clap.git"
//! ```
//!
//! Add `extern crate clap;` to your crate root.
//!
//! Define a list of valid arguments for your program (see the
//! [documentation](https://docs.rs/clap/) or [examples/] directory of this repo)
//!
//! Then run `cargo build` or `cargo update && cargo build` for your project.
//!
//! ### Optional Dependencies / Features
//!
//! #### Features enabled by default
//!
//! * `suggestions`: Turns on the `Did you mean '--myoption'?` feature for when users make typos. (builds dependency `strsim`)
//! * `color`: Turns on colored error messages. This feature only works on non-Windows OSs. (builds dependency `ansi-term` and `atty`)
//! * `wrap_help`: Wraps the help at the actual terminal width when
//!  available, instead of 120 characters. (builds dependency `textwrap`
//! with feature `term_size`)
//!
//! To disable these, add this to your `Cargo.toml`:
//!
//! ```toml
//! [dependencies.clap]
//! version = "~2.27.0"
//! default-features = false
//! ```
//!
//! You can also selectively enable only the features you'd like to include, by adding:
//!
//! ```toml
//! [dependencies.clap]
//! version = "~2.27.0"
//! default-features = false
//!
//! # Cherry-pick the features you'd like to use
//! features = [ "suggestions", "color" ]
//! ```
//!
//! #### Opt-in features
//!
//! * **"yaml"**: Enables building CLIs from YAML documents. (builds dependency `yaml-rust`)
//! * **"unstable"**: Enables unstable `clap` features that may change from release to release
//!
//! ### Dependencies Tree
//!
//! The following graphic depicts `clap`s dependency graph (generated using
//! [cargo-graph](https://github.com/kbknapp/cargo-graph)).
//!
//!  * **Dashed** Line: Optional dependency
//!  * **Red** Color: **NOT** included by default (must use cargo `features` to enable)
//!  * **Blue** Color: Dev dependency, only used while developing.
//!
//! ![clap dependencies](https://raw.githubusercontent.com/clap-rs/clap/master/clap_dep_graph.png)
//!
//! ### More Information
//!
//! You can find complete documentation on the [docs.rs](https://docs.rs/clap/) for this project.
//!
//! You can also find usage examples in the [examples/] directory of this repo.
//!
//! #### Video Tutorials
//!
//! There's also the video tutorial series [Argument Parsing with Rust v2][video tutorials].
//!
//! These videos slowly trickle out as I finish them and currently a work in progress.
//!
//! ## 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!
//!
//! 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 :)
//!
//! Please read [CONTRIBUTING.md](https://raw.githubusercontent.com/clap-rs/clap/master/.github/CONTRIBUTING.md) before you start contributing.
//!
//!
//! ### Testing Code
//!
//! To test with all features both enabled and disabled, you can run theese commands:
//!
//! ```text
//! $ cargo test --no-default-features
//! $ cargo test --features "yaml unstable"
//! ```
//!
//! Alternatively, if you have [`just`](https://github.com/casey/just) installed you can run the
//! prebuilt recipes. *Not* using `just` is perfectly fine as well, it simply bundles commands
//! automatically.
//!
//! For example, to test the code, as above simply run:
//!
//! ```text
//! $ just run-tests
//! ```
//!
//! From here on, I will list the appropriate `cargo` command as well as the `just` command.
//!
//! Sometimes it's helpful to only run a subset of the tests, which can be done via:
//!
//! ```text
//! $ cargo test --test <test_name>
//!
//! # Or
//!
//! $ just run-test <test_name>
//! ```
//!
//! ### Linting Code
//!
//! During the CI process `clap` runs against many different lints using
//! [`clippy`](https://github.com/Manishearth/rust-clippy). In order to check if these lints pass on
//! your own computer prior to submitting a PR you'll need a nightly compiler.
//!
//! In order to check the code for lints run either:
//!
//! ```text
//! $ rustup override add nightly
//! $ cargo build --features lints
//! $ rustup override remove
//!
//! # Or
//!
//! $ just lint
//! ```
//!
//! ### Debugging Code
//!
//! Another helpful technique is to see the `clap` debug output while developing features. In order
//! to see the debug output while running the full test suite or individual tests, run:
//!
//! ```text
//! $ cargo test --features debug
//!
//! # Or for individual tests
//! $ cargo test --test <test_name> --features debug
//!
//! # The corresponding just command for individual debugging tests is:
//! $ just debug <test_name>
//! ```
//!
//! ### Goals
//!
//! 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).
//!
//! * 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 (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
//!
//! ### Compatibility Policy
//!
//! Because `clap` takes `SemVer` and compatibility seriously, this is the official policy regarding
//! breaking changes and previous versions of Rust.
//!
//! `clap` will pin the minimum required version of Rust to the CI builds. Bumping the minimum
//! version of Rust is considered a minor breaking change, meaning *at a minimum* the minor version
//! of `clap` will be bumped.
//!
//! In order to keep from being surprised by breaking changes, it is **highly** recommended to use
//! the `~major.minor.patch` style in your `Cargo.toml`:
//!
//! ```toml
//! [dependencies] clap = "~2.27.0"
//! ```
//!
//! This will cause *only* the patch version to be updated upon a `cargo update` call, and therefore
//! cannot break due to new features, or bumped minimum versions of Rust.
//!
//! #### Minimum Version of Rust
//!
//! `clap` will officially support current stable Rust, minus two releases, but may work with prior
//! releases as well. For example, current stable Rust at the time of this writing is 1.21.0,
//! meaning `clap` is guaranteed to compile with 1.19.0 and beyond. At the 1.22.0 release, `clap`
//! will be guaranteed to compile with 1.20.0 and beyond, etc.
//!
//! Upon bumping the minimum version of Rust (assuming it's within the stable-2 range), it *must* be
//! clearly annotated in the `CHANGELOG.md`
//!
//! ## License
//!
//! `clap` is licensed under the MIT license. Please read the [LICENSE-MIT][license] file in
//! this repository for more information.
//!
//! [examples/]: https://github.com/clap-rs/clap/tree/master/examples
//! [video tutorials]: https://www.youtube.com/playlist?list=PLza5oFLQGTl2Z5T8g1pRkIynR3E0_pc7U
//! [license]: https://raw.githubusercontent.com/clap-rs/clap/master/LICENSE-MIT

#![crate_type = "lib"]
#![doc(html_root_url = "https://docs.rs/clap/2.33.1")]
#![deny(
    missing_docs,
    missing_debug_implementations,
    missing_copy_implementations,
    trivial_casts,
    unused_import_braces,
    unused_allocation
)]
// Lints we'd like to deny but are currently failing for upstream crates
//      unused_qualifications       (bitflags, clippy)
//      trivial_numeric_casts       (bitflags)
#![cfg_attr(
    not(any(feature = "lints", feature = "nightly")),
    forbid(unstable_features)
)]
#![cfg_attr(feature = "lints", feature(plugin))]
#![cfg_attr(feature = "lints", plugin(clippy))]
// Need to disable deny(warnings) while deprecations are active
// #![cfg_attr(feature = "lints", deny(warnings))]
#![cfg_attr(feature = "lints", allow(cyclomatic_complexity))]
#![cfg_attr(feature = "lints", allow(doc_markdown))]
#![cfg_attr(feature = "lints", allow(explicit_iter_loop))]

#[cfg(all(feature = "color", not(target_os = "windows")))]
extern crate ansi_term;
#[cfg(feature = "color")]
extern crate atty;
#[macro_use]
extern crate bitflags;
#[cfg(feature = "suggestions")]
extern crate strsim;
#[cfg(feature = "wrap_help")]
extern crate term_size;
extern crate textwrap;
extern crate unicode_width;
#[cfg(feature = "vec_map")]
extern crate vec_map;
#[cfg(feature = "yaml")]
extern crate yaml_rust;

pub use app::{App, AppSettings};
pub use args::{Arg, ArgGroup, ArgMatches, ArgSettings, OsValues, SubCommand, Values};
pub use completions::Shell;
pub use errors::{Error, ErrorKind, Result};
pub use fmt::Format;
#[cfg(feature = "yaml")]
pub use yaml_rust::YamlLoader;

#[macro_use]
mod macros;
mod app;
mod args;
mod completions;
mod errors;
mod fmt;
mod map;
mod osstringext;
mod strext;
mod suggestions;
mod usage_parser;

const INTERNAL_ERROR_MSG: &'static str = "Fatal internal error. Please consider filing a bug \
                                          report at https://github.com/clap-rs/clap/issues";
const INVALID_UTF8: &'static str = "unexpected invalid UTF-8 code point";

#[cfg(unstable)]
pub use derive::{ArgEnum, ClapApp, FromArgMatches, IntoApp};

#[cfg(unstable)]
mod derive {
    /// @TODO @release @docs
    pub trait ClapApp: IntoApp + FromArgMatches + Sized {
        /// @TODO @release @docs
        fn parse() -> Self {
            Self::from_argmatches(Self::into_app().get_matches())
        }

        /// @TODO @release @docs
        fn parse_from<I, T>(argv: I) -> Self
        where
            I: IntoIterator<Item = T>,
            T: Into<OsString> + Clone,
        {
            Self::from_argmatches(Self::into_app().get_matches_from(argv))
        }

        /// @TODO @release @docs
        fn try_parse() -> Result<Self, clap::Error> {
            Self::try_from_argmatches(Self::into_app().get_matches_safe()?)
        }

        /// @TODO @release @docs
        fn try_parse_from<I, T>(argv: I) -> Result<Self, clap::Error>
        where
            I: IntoIterator<Item = T>,
            T: Into<OsString> + Clone,
        {
            Self::try_from_argmatches(Self::into_app().get_matches_from_safe(argv)?)
        }
    }

    /// @TODO @release @docs
    pub trait IntoApp {
        /// @TODO @release @docs
        fn into_app<'a, 'b>() -> clap::App<'a, 'b>;
    }

    /// @TODO @release @docs
    pub trait FromArgMatches: Sized {
        /// @TODO @release @docs
        fn from_argmatches<'a>(matches: clap::ArgMatches<'a>) -> Self;

        /// @TODO @release @docs
        fn try_from_argmatches<'a>(matches: clap::ArgMatches<'a>) -> Result<Self, clap::Error>;
    }

    /// @TODO @release @docs
    pub trait ArgEnum {}
}