Struct otter_base::prelude::fmt::Arguments 1.0.0[−][src]
pub struct Arguments<'a> { /* fields omitted */ }
Expand description
This structure represents a safely precompiled version of a format string and its arguments. This cannot be generated at runtime because it cannot safely be done, so no constructors are given and the fields are private to prevent modification.
The format_args!
macro will safely create an instance of this structure.
The macro validates the format string at compile-time so usage of the
write()
and format()
functions can be safely performed.
You can use the Arguments<'a>
that format_args!
returns in Debug
and Display
contexts as seen below. The example also shows that Debug
and Display
format to the same thing: the interpolated format string
in format_args!
.
let debug = format!("{:?}", format_args!("{} foo {:?}", 1, 2)); let display = format!("{}", format_args!("{} foo {:?}", 1, 2)); assert_eq!("1 foo 2", display); assert_eq!(display, debug);
Implementations
Get the formatted string, if it has no arguments to be formatted.
This can be used to avoid allocations in the most trivial case.
Examples
use std::fmt::Arguments; fn write_str(_: &str) { /* ... */ } fn write_fmt(args: &Arguments) { if let Some(s) = args.as_str() { write_str(s) } else { write_str(&args.to_string()); } }
assert_eq!(format_args!("hello").as_str(), Some("hello")); assert_eq!(format_args!("").as_str(), Some("")); assert_eq!(format_args!("{}", 1).as_str(), None);
Trait Implementations
pub fn serialize<S>(
&self,
serializer: S
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error> where
S: Serializer,
pub fn serialize<S>(
&self,
serializer: S
) -> Result<<S as Serializer>::Ok, <S as Serializer>::Error> where
S: Serializer,
Serialize this value into the given Serde serializer. Read more
type Error = CapacityError<Error>
type Error = CapacityError<Error>
The type returned in the event of a conversion error.
pub fn try_from(
f: Arguments<'a>
) -> Result<ArrayString<CAP>, <ArrayString<CAP> as TryFrom<Arguments<'a>>>::Error>
pub fn try_from(
f: Arguments<'a>
) -> Result<ArrayString<CAP>, <ArrayString<CAP> as TryFrom<Arguments<'a>>>::Error>
Performs the conversion.
Auto Trait Implementations
impl<'a> !RefUnwindSafe for Arguments<'a>
impl<'a> !UnwindSafe for Arguments<'a>
Blanket Implementations
Mutably borrows from an owned value. Read more