<details><summary>Combinatoric example</summary>
```no_run
#[derive(Debug, Clone)]
pub struct Options {
argument: Vec<u32>,
switches: Vec<bool>,
}
pub fn options() -> OptionParser<Options> {
let argument = long("argument")
.help("important argument")
.argument("ARG")
.some("want at least one argument");
let switches = long("switch")
.help("some switch")
.req_flag(true)
.some("want at least one switch");
construct!(Options { argument, switches }).to_options()
}
fn main() {
println!("{:?}", options().run())
}
```
</details>
<details><summary>Derive example</summary>
```no_run
#[derive(Debug, Clone, Bpaf)]
#[bpaf(options)]
pub struct Options {
/// important argument
#[bpaf(argument("ARG"), some("want at least one argument"))]
argument: Vec<u32>,
/// some switch
#[bpaf(long("switch"), req_flag(true), some("want at least one switch"))]
switches: Vec<bool>,
}
fn main() {
println!("{:?}", options().run())
}
```
</details>
<details><summary>Output</summary>
In usage lines `some` items are indicated with `...`
<div class='bpaf-doc'>
$ app --help<br>
<p><b>Usage</b>: <tt><b>app</b></tt> <tt><b>--argument</b></tt>=<tt><i>ARG</i></tt>... <tt><b>--switch</b></tt>...</p><p><div>
<b>Available options:</b></div><dl><dt><tt><b> --argument</b></tt>=<tt><i>ARG</i></tt></dt>
<dd>important argument</dd>
<dt><tt><b> --switch</b></tt></dt>
<dd>some switch</dd>
<dt><tt><b>-h</b></tt>, <tt><b>--help</b></tt></dt>
<dd>Prints help information</dd>
</dl>
</p>
<style>
div.bpaf-doc {
padding: 14px;
background-color:var(--code-block-background-color);
font-family: "Source Code Pro", monospace;
margin-bottom: 0.75em;
}
div.bpaf-doc dt { margin-left: 1em; }
div.bpaf-doc dd { margin-left: 3em; }
div.bpaf-doc dl { margin-top: 0; padding-left: 1em; }
div.bpaf-doc { padding-left: 1em; }
</style>
</div>
Run inner parser as many times as possible collecting all the new results, but unlike
`many` needs to collect at least one element to succeed
<div class='bpaf-doc'>
$ app --argument 10 --argument 20 --switch<br>
Options { argument: [10, 20], switches: [true] }
</div>
With not enough parameters to satisfy both parsers at least once - it fails
<div class='bpaf-doc'>
$ app <br>
<b>Error:</b> want at least one argument
<style>
div.bpaf-doc {
padding: 14px;
background-color:var(--code-block-background-color);
font-family: "Source Code Pro", monospace;
margin-bottom: 0.75em;
}
div.bpaf-doc dt { margin-left: 1em; }
div.bpaf-doc dd { margin-left: 3em; }
div.bpaf-doc dl { margin-top: 0; padding-left: 1em; }
div.bpaf-doc { padding-left: 1em; }
</style>
</div>
both parsers need to succeed to create a struct
<div class='bpaf-doc'>
$ app --argument 10<br>
<b>Error:</b> want at least one switch
<style>
div.bpaf-doc {
padding: 14px;
background-color:var(--code-block-background-color);
font-family: "Source Code Pro", monospace;
margin-bottom: 0.75em;
}
div.bpaf-doc dt { margin-left: 1em; }
div.bpaf-doc dd { margin-left: 3em; }
div.bpaf-doc dl { margin-top: 0; padding-left: 1em; }
div.bpaf-doc { padding-left: 1em; }
</style>
</div>
For parsers that can succeed without consuming anything such as `flag` or `switch` - `some`
only collects values as long as they produce something
<div class='bpaf-doc'>
$ app --switch --argument 10<br>
Options { argument: [10], switches: [true] }
</div>
</details>