Passing empty values, such as `--feature ""` now stores the empty string
correctly as a value (assuming empty values are allowed as per the arg
configuration)
Closes#470
Now if the terminal size is too small to properly wrap the help text
lines, it will default to just wrapping normalling as it should.
This is determined on a per help text basis, so because the terminal
size is too small for a single argument's help to wrap properly, all
other arguments will still wrap and align correctly. Only the one
affected argument will not align properly.
Closes#453
The `help` subcommand can now accept other subcommands as arguments to
display their help message. This is similar to how many other CLIs
already perform. For example:
```
$ myprog help mysubcmd
```
Would print the help message for `mysubcmd`. But even more, the `help`
subcommand accepts nested subcommands as well, i.e. a grandchild
subcommand such as
```
$ myprog help child grandchild
```
Would print the help message of `grandchild` where `grandchild` is a
subcommand of `child` and `child` is a subcommand of `myprog`.
Closes#416
By default `clap` now automatically wraps and aligns help strings to the
term width. i.e.
```
-o, --option <opt> some really long help
text that should be auto aligned but isn't righ
t now
```
Now looks like this:
```
-o, --option <opt> some really long help
text that should be
auto aligned but isn't
right now
```
The wrapping also respects words, and wraps at spaces so as to not cut
words in the middle.
This requires the `libc` dep which is enabled (by default) with the
`wrap_help` cargo feature flag.
Closes#428
Args and subcommands can now have their display order automatically
derived by using the setting `AppSettings::DeriveDisplayOrder` which
will display the args and subcommands in the order that they were
declared in, instead of alphabetical order which is the default.
Closes#444
Allows custom ordering of subcommands within the help message. Subcommands with a lower
value will be displayed first in the help message. This is helpful when one would like to
emphasise frequently used subcommands, or prioritize those towards the top of the list.
Duplicate values **are** allowed. Subcommands with duplicate display orders will be
displayed in alphabetical order.
**NOTE:** The default is 999 for all subcommands.
```rust
use clap::{App, SubCommand};
let m = App::new("cust-ord")
.subcommand(SubCommand::with_name("alpha") // typically subcommands are grouped
// alphabetically by name. Subcommands
// without a display_order have a value of
// 999 and are displayed alphabetically with
// all other 999 subcommands
.about("Some help and text"))
.subcommand(SubCommand::with_name("beta")
.display_order(1) // In order to force this subcommand to appear *first*
// all we have to do is give it a value lower than 999.
// Any other subcommands with a value of 1 will be displayed
// alphabetically with this one...then 2 values, then 3, etc.
.about("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
SUBCOMMANDS:
beta I should be first!
alpha Some help and text
```
Closes#442
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
```
