Allows custom ordering of args within the help message. Args with a lower value will be
displayed first in the help message. This is helpful when one would like to emphasise
frequently used args, or prioritize those towards the top of the list. Duplicate values
**are** allowed. Args with duplicate display orders will be displayed in alphabetical
order.
**NOTE:** The default is 999 for all arguments.
**NOTE:** This setting is ignored for positional arguments which are always displayed in
index order.
```rust
use clap::{App, Arg};
let m = App::new("cust-ord")
.arg(Arg::with_name("a") // typically args are grouped by alphabetically by name
// Args without a display_order have a value of 999 and are
// displayed alphabetically with all other 999 args
.long("long-option")
.short("o")
.takes_value(true)
.help("Some help and text"))
.arg(Arg::with_name("b")
.long("other-option")
.short("O")
.takes_value(true)
.display_order(1) // Let's force this arg to appear *first*
// all we have to do is give it a value lower than 999
// any other args with a value of 1 would be displayed
// alphabetically with other 1 args. Then 2, then 3, etc.
.help("I should be first!"))
.get_matches_from(vec![
"cust-ord", "--help"
]);
```
The above example displays the following help message
```
cust-ord
USAGE:
cust-ord [FLAGS] [OPTIONS]
FLAGS:
-h, --help Prints help information
-V, --version Prints version information
OPTIONS:
-O, --other-option <b> I should be first!
-o, --long-option <a> Some help and text
```
OsStr recently gained unstable inherent methods with the same name. This rename
makes sure we don't call the inherent methods but the methods provided by this
extension trait.
Adds a setting for both `AppSettings` and an `Arg` method which allows
placing the help text for a particular argument (or all arguments via
the `AppSettings`) on the line after the argument itself and indented
once.
This is useful for when a single argument may have a very long
invocation flag, or many value names which throws off the alignment of
al other arguments. On a small terminal this can be terrible. Placing
the text on the line below the argument solves this issue. This is also
how many of the GNU utilities display their help strings for individual
arguments.
The final caes where this can be hepful is if the argument has a very
long or detailed and complex help string that will span multiple lines.
It can be visually more appealing and easier to read when those lines
don't wrap as frequently since there is more space on the next line.
Closes#427
i.e. assume, option -O set to multiple, and number_of_values(1)
set. And assume a *required* positional argument is also set.
-O some -O other pos
Would fail with pos arg not supplied.
Relates to #415
By using AppSettings::AllowLeadingHyphen values starting with a
leading hyphen (such as a negative number) are supported. This
setting should be used with caution as it silences certain
circumstances which would otherwise be an error (like forgetting
a value to an option argument).
Closes#385
This commit adds support for values separated by commas such as
--option=val1,val2,val3. It also includes support for uses
without the equals and shorts (both with and without)
--option=val1,val2
--option val1,val2
-oval1,val2
-o=val1,val2
-o val1,val2
Closes#348
