The following completion would happen (using example 17_yaml.rs):
```
$ prog <tab>
help subcmd
```
```
$ prog -<tab><tab>
--help -h (Prints help information)
--max-vals (you can only supply a max of 3 values for me!)
--min-vals (you must supply at least two values to satisfy me)
--mode (shows an option with specific values)
--mult-vals (demos an option which has two named values)
--option -o (example option argument from yaml)
--version -V (Prints version information)
-F (demo flag argument)
```
```
$ prog --<tab><tab>
--help -h (Prints help information)
--max-vals (you can only supply a max of 3 values for me!)
--min-vals (you must supply at least two values to satisfy me)
--mode (shows an option with specific values)
--mult-vals (demos an option which has two named values)
--option -o (example option argument from yaml)
--version -V (Prints version information)
```
```
$ prog --mode <tab>
emacs (shows an option with specific values) vi (shows an option with specific values)
```
```
$ prog subcmd -<tab>
--help -h (Prints help information) -B (example subcommand option)
--version -V (Prints version information)
```
```
$ prog subcmd --<tab>
--help (Prints help information) --version (Prints version information)
```
Close#578
* test: `require_unless_one` with second argument
Add the `require_unless_one_2` test. This tests that when the second
argument in the array is used at the command line, that the required
argument is not present. This test was added because it appears the
`require_unless_one` function only works for the first argument in the
array.
* Fix: assertions for test
The assertions did not check for the `infile` to be present.
add `gen_completions_to`
to write completions to buffer (e.g. stdout) instead of file. fixes#566
(for review; will fix commit message when done)
still pretty new to rust so comments on anything from style to structure would be must appreciated!
Fix the formatting in the completions example
A missing newline prevented the Cargo.toml excerpt in the `gen_completions` example from being properly formatted.
