clap/examples/escaped-positional-derive.md
Ed Page 162a556dba fix(error): Try to soften unexpected argument/value errors
Adding "found" might seem minor but I feel it has a slight softening on the message.  It also maintains scanability as it is at the end and short.

As this is a one-off message change and not a styling issue to be consistent with, I think this is safe to put in a patch release.
2023-01-13 21:29:49 -06:00

60 lines
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Markdown

**This requires enabling the [`derive` feature flag][crate::_features].**
You can use `--` to escape further arguments.
Let's see what this looks like in the help:
```console
$ escaped-positional-derive --help
A simple to use, efficient, and full-featured Command Line Argument Parser
Usage: escaped-positional-derive[EXE] [OPTIONS] [-- <SLOP>...]
Arguments:
[SLOP]...
Options:
-f
-p <PEAR>
-h, --help Print help
-V, --version Print version
```
Here is a baseline without any arguments:
```console
$ escaped-positional-derive
-f used: false
-p's value: None
'slops' values: []
```
Notice that we can't pass positional arguments before `--`:
```console
$ escaped-positional-derive foo bar
? failed
error: unexpected argument 'foo' found
Usage: escaped-positional-derive[EXE] [OPTIONS] [-- <SLOP>...]
For more information, try '--help'.
```
But you can after:
```console
$ escaped-positional-derive -f -p=bob -- sloppy slop slop
-f used: true
-p's value: Some("bob")
'slops' values: ["sloppy", "slop", "slop"]
```
As mentioned, the parser will directly pass everything through:
```console
$ escaped-positional-derive -- -f -p=bob sloppy slop slop
-f used: false
-p's value: None
'slops' values: ["-f", "-p=bob", "sloppy", "slop", "slop"]
```