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
