Struct Formatter 

pub struct Formatter<'a> { /* private fields */ }

The per-value formatting context passed to DynDisplay::dyn_fmt.

This type mirrors std::fmt::Formatter: it bundles the FormatSpec with the output sink and exposes convenience methods for writing padded output.

It implements std::fmt::Write, so write!(f, ...) works naturally inside a DynDisplay::dyn_fmt implementation.

Examples

Using write! directly — padding is applied automatically:

use dyf::{DynDisplay, Formatter};
use std::fmt::Write;

struct Point { x: i32, y: i32 }

impl DynDisplay for Point {
    fn dyn_fmt(&self, f: &mut Formatter<'_>) -> dyf::Result {
        Ok(write!(f, "Point({}, {})", self.x, self.y)?)
    }
}

Implementations

impl<'a> Formatter<'a>

pub fn new(spec: &'a FormatSpec, out: &'a mut dyn Write) -> Self

Creates a new Formatter wrapping the given spec and output sink.

pub fn spec(&self) -> &FormatSpec

Returns the full FormatSpec.

pub fn fill(&self) -> char

Returns the fill character (defaults to ' ').

pub fn align(&self) -> Align

Returns the effective alignment: the value from the format spec if one was explicitly requested, otherwise the default set by Formatter::set_default_align.

pub fn width(&self) -> Option<usize>

Returns the minimum field width, if specified.

pub fn precision(&self) -> Option<usize>

Returns the precision, if specified.

pub fn sign(&self) -> Option<Sign>

Returns the sign option, if any.

pub fn alternate(&self) -> bool

Returns true if the alternate form (#) was requested.

pub fn zero(&self) -> bool

Returns true if zero-padding (0) was requested.

pub fn fmt_type(&self) -> FmtType

Returns the format type (e.g. FmtType::LowerHex, FmtType::Debug).

pub fn set_default_align(&mut self, align: Align)

Sets the default alignment used when none is specified in the format string.

Overrides the initial Left default. Call this before write!(f, ...) when implementing a type that should right-align by default (e.g. a custom numeric type).

Trait Implementations

impl Write for Formatter<'_>

fn write_str(&mut self, s: &str) -> Result

Writes a string slice into this writer, returning whether the write succeeded.

fn write_char(&mut self, c: char) -> Result

Writes a char into this writer, returning whether the write succeeded.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<(), Error>

Glue for usage of the write! macro with implementors of this trait.