An arg can now be conditionally required (i.e. it's only required if arg
A is used with a value of V).
For example:
```rust
let res = App::new("ri")
.arg(Arg::with_name("cfg")
.required_if("extra", "val")
.takes_value(true)
.long("config"))
.arg(Arg::with_name("extra")
.takes_value(true)
.long("extra"))
.get_matches_from_safe(vec![
"ri", "--extra", "val"
]);
assert!(res.is_err());
assert_eq!(res.unwrap_err().kind, ErrorKind::MissingRequiredArgument);
```
Relates to #764
An arg can now conditionally require additional arguments if it's value matches a specific value.
For example, arg A can state that it only requires arg B if the value X was used with arg A. If any
other value is used with A, arg B isn't required.
Relates to #764
One can now implement conditional default values. I.e. a default value that is only applied in
certain conditions, such as another arg being present, or another arg being present *and*
containing a specific value.
Now it's possible to say, "Only apply this default value if arg X is present" or "Only apply this
value if arg X is present, but also only if arg X's value is equal to Y"
This new method is fully compatible with the current `Arg::default_value`, which gets set only if
the arg wasn't used at runtime *and* none of the specified conditions were met.
Releates to #764
Instead of using Format::Error directly, we need to use a Colorizer to
make sure that the message only gets colorized when it is appropriate
to do so.
Fixes#775
The implementation is basically manually expanded lazy_static! macro
(with some hand-crafted simplifications and inlining), since you can't
use extern crates (and therefore import macros therefrom) in macros.
This ensures that you get this:
p:\Rust\http>target\debug\http -h
http 0.1.0
thecoshman <thecoshman@gmail.com>
nabijaczleweli <nabijaczleweli@gmail.com>
Host These Things Please - a basic HTTP server for hosting a folder fast and simply
Instead of this:
p:\Rust\http>target\debug\http -h
http 0.1.0
thecoshman <thecoshman@gmail.com>:nabijaczleweli <nabijaczleweli@gmail.com>
Host These Things Please - a basic HTTP server for hosting a folder fast and simply
Closes#779
Since ZSH completions use `[ and ]` for descriptions, but clap args use `[ and ]` for possible
values and other auxillary arg information, this was creating a conflict. clap now escapes any
square brackets before writing the help, i.e. `\\[ and \\]` which removes conflicts.
Alternatives would be to switch `[ and ]` for `( and )` but this would create a slight difference
in help messages and completions.
Closes#771
imp(Completions): adds fallbacks to Bash completions
With these options, in case the completion function cannot provide suggestions, Bash will perform its default completions, based on e.g. files, directories, and variable names.
This is particularly noticeable in tools that operate on paths, like ripgrep: when I type `rg should_panic te<TAB>`, I want the shell to autocomplete `tests/`, but right now the completion script will simply beep without any suggestions.
With these options, in case the completion function cannot provide
suggestions, Bash will perform its default completions, based on e.g.
files, directories, and variable names. This is particularly useful for
argument values.
