Trait frame_support::dispatch::fmt::UpperHex
1.0.0 · source · pub trait UpperHex {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}Expand description
X formatting.
The UpperHex trait should format its output as a number in hexadecimal, with A through F
in upper case.
For primitive signed integers (i8 to i128, and isize),
negative values are formatted as the two’s complement representation.
The alternate flag, #, adds a 0x in front of the output.
For more information on formatters, see the module-level documentation.
Examples
Basic usage with i32:
let x = 42; // 42 is '2A' in hex
assert_eq!(format!("{x:X}"), "2A");
assert_eq!(format!("{x:#X}"), "0x2A");
assert_eq!(format!("{:X}", -16), "FFFFFFF0");Implementing UpperHex on a type:
use std::fmt;
struct Length(i32);
impl fmt::UpperHex for Length {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let val = self.0;
fmt::UpperHex::fmt(&val, f) // delegate to i32's implementation
}
}
let l = Length(i32::MAX);
assert_eq!(format!("l as hex is: {l:X}"), "l as hex is: 7FFFFFFF");
assert_eq!(format!("l as hex is: {l:#010X}"), "l as hex is: 0x7FFFFFFF");