Struct scale_info::prelude::fmt::Arguments1.0.0[][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

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Formats the value using the given formatter. Read more

Serialize this value into the given Serde serializer. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Converts self into T using Into<T>. Read more

Converts self into a target type. Read more

Causes self to use its Binary implementation when Debug-formatted.

Causes self to use its Display implementation when Debug-formatted. Read more

Causes self to use its LowerExp implementation when Debug-formatted. Read more

Causes self to use its LowerHex implementation when Debug-formatted. Read more

Causes self to use its Octal implementation when Debug-formatted.

Causes self to use its Pointer implementation when Debug-formatted. Read more

Causes self to use its UpperExp implementation when Debug-formatted. Read more

Causes self to use its UpperHex implementation when Debug-formatted. Read more

Performs the conversion.

Performs the conversion.

Pipes by value. This is generally the method you want to use. Read more

Borrows self and passes that borrow into the pipe function. Read more

Mutably borrows self and passes that borrow into the pipe function. Read more

Borrows self, then passes self.borrow() into the pipe function. Read more

Mutably borrows self, then passes self.borrow_mut() into the pipe function. Read more

Borrows self, then passes self.as_ref() into the pipe function.

Mutably borrows self, then passes self.as_mut() into the pipe function. Read more

Borrows self, then passes self.deref() into the pipe function.

Mutably borrows self, then passes self.deref_mut() into the pipe function. Read more

Pipes a value into a function that cannot ordinarily be called in suffix position. Read more

Pipes a trait borrow into a function that cannot normally be called in suffix position. Read more

Pipes a trait mutable borrow into a function that cannot normally be called in suffix position. Read more

Pipes a trait borrow into a function that cannot normally be called in suffix position. Read more

Pipes a trait mutable borrow into a function that cannot normally be called in suffix position. Read more

Pipes a dereference into a function that cannot normally be called in suffix position. Read more

Pipes a mutable dereference into a function that cannot normally be called in suffix position. Read more

Pipes a reference into a function that cannot ordinarily be called in suffix position. Read more

Pipes a mutable reference into a function that cannot ordinarily be called in suffix position. Read more

Immutable access to a value. Read more

Mutable access to a value. Read more

Immutable access to the Borrow<B> of a value. Read more

Mutable access to the BorrowMut<B> of a value. Read more

Immutable access to the AsRef<R> view of a value. Read more

Mutable access to the AsMut<R> view of a value. Read more

Immutable access to the Deref::Target of a value. Read more

Mutable access to the Deref::Target of a value. Read more

Calls .tap() only in debug builds, and is erased in release builds.

Calls .tap_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_borrow() only in debug builds, and is erased in release builds. Read more

Calls .tap_borrow_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_ref() only in debug builds, and is erased in release builds. Read more

Calls .tap_ref_mut() only in debug builds, and is erased in release builds. Read more

Calls .tap_deref() only in debug builds, and is erased in release builds. Read more

Calls .tap_deref_mut() only in debug builds, and is erased in release builds. Read more

Provides immutable access for inspection. Read more

Calls tap in debug builds, and does nothing in release builds.

Provides mutable access for modification. Read more

Calls tap_mut in debug builds, and does nothing in release builds.

Provides immutable access to the reference for inspection.

Calls tap_ref in debug builds, and does nothing in release builds.

Provides mutable access to the reference for modification.

Calls tap_ref_mut in debug builds, and does nothing in release builds.

Provides immutable access to the borrow for inspection. Read more

Calls tap_borrow in debug builds, and does nothing in release builds.

Provides mutable access to the borrow for modification.

Calls tap_borrow_mut in debug builds, and does nothing in release builds. Read more

Immutably dereferences self for inspection.

Calls tap_deref in debug builds, and does nothing in release builds.

Mutably dereferences self for modification.

Calls tap_deref_mut in debug builds, and does nothing in release builds. Read more

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

🔬 This is a nightly-only experimental API. (toowned_clone_into)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

Converts the given value to a String. Read more

Attempts to convert self into T using TryInto<T>. Read more

Attempts to convert self into a target type. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.