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use super::{Align, Base, NumFmt, Sign};
/// Builder for a numeric formatter.
#[derive(Clone, PartialEq, Eq, Debug, Default)]
pub struct Builder {
fill: Option<char>,
align: Align,
sign: Sign,
hash: bool,
zero: bool,
width: usize,
precision: Option<usize>,
format: Base,
separator: Option<char>,
spacing: Option<usize>,
decimal_separator: Option<char>,
}
impl Builder {
/// Construct a new `Builder`.
pub fn new() -> Builder {
Self::default()
}
/// Build a [`NumFmt`] instance, consuming this builder.
pub fn build(self) -> NumFmt {
let Builder {
fill,
align,
sign,
hash,
zero,
width,
precision,
format,
separator,
spacing,
decimal_separator,
} = self;
NumFmt {
fill,
align,
sign,
hash,
zero,
width,
precision,
base: format,
separator,
spacing,
decimal_separator,
}
}
/// When `width` is greater than the actual rendered width of the number, the excess is padded
/// with this character.
///
/// ## Note
/// Wide characters are counted according to their quantity, not their bit width.
///
/// ```rust
/// # use num_runtime_fmt::NumFmt;
/// let heart = '🖤';
/// assert_eq!(heart.len_utf8(), 4);
/// let fmt = NumFmt::builder().fill(heart).width(3).build();
/// let formatted = fmt.fmt(1).unwrap();
/// assert_eq!(formatted, "🖤🖤1");
/// // Note that even though we requested a width of 3, the binary length is 9.
/// assert_eq!(formatted.len(), 9);
/// ```
#[inline]
pub fn fill(mut self, param: char) -> Self {
self.fill = Some(param);
self
}
/// Set the alignment of rendering within allotted `width`. See [`Align`].
#[inline]
pub fn align(mut self, param: Align) -> Self {
self.align = param;
self
}
/// Set the rendering of the sign. See [`Sign`].
#[inline]
pub fn sign(mut self, param: Sign) -> Self {
self.sign = param;
self
}
/// If a `set`, print a base specification before the number
/// according to its format.
///
/// See [`Builder::format`].
///
/// - binary: `0b`
/// - octal: `0o`
/// - decimal: `0d`
/// - hex: `0x`
///
/// Corresponds to the `#` format specifier.
#[inline]
pub fn hash(mut self, set: bool) -> Self {
self.hash = set;
self
}
/// If `set`, engage the zero handler.
///
/// The zero handler overrides the padding specification to `0`, and
/// treats pad characters as part of the number, in contrast
/// to the default behavior which treats them as arbitrary spacing.
///
/// Only valid with `Align::Right` and `Align::Decimal`.
///
/// ## Examples
///
/// ```rust
/// # use num_runtime_fmt::NumFmt;
/// // sign handling
/// assert_eq!(NumFmt::from_str("03").unwrap().fmt(-1).unwrap(), "-01");
/// assert_eq!(NumFmt::from_str("0>3").unwrap().fmt(-1).unwrap(), "0-1");
/// ```
///
/// ```rust
/// # use num_runtime_fmt::NumFmt;
/// // separator handling
/// assert_eq!(NumFmt::from_str("0>7,").unwrap().fmt(1).unwrap(), "0000001");
/// assert_eq!(NumFmt::from_str("07,").unwrap().fmt(1).unwrap(), "000,001");
/// ```
#[inline]
pub fn zero(mut self, set: bool) -> Self {
if set {
self.fill = Some('0');
self.zero = true;
} else {
self.fill = None;
self.zero = false;
}
self
}
/// Set the `width` parameter.
///
/// This is a parameter for the "minimum width" that the format should take up. If
/// the value's string does not fill up this many characters, then the padding
/// specified by fill/alignment will be used to take up the required space (see
/// [`Builder::fill`]).
///
/// The width can be set dynamically:
///
/// ```rust
/// # use num_runtime_fmt::{NumFmt, Dynamic};
/// assert_eq!(NumFmt::from_str("-^").unwrap().fmt_with(1, Dynamic::width(5)).unwrap(), "--1--");
/// ```
///
/// Note: with `Align::Right`, this is the minimum width of the entire rendered field,
/// not just the portion before the decimal. To set the width before the decimal,
/// use `Align::Decimal`.
///
/// ```rust
/// # use num_runtime_fmt::{NumFmt, Dynamic};
/// assert_eq!(NumFmt::from_str( "05").unwrap().fmt(1.1).unwrap(), "001.1");
/// assert_eq!(NumFmt::from_str(">05").unwrap().fmt(1.1).unwrap(), "001.1");
/// assert_eq!(NumFmt::from_str("v05").unwrap().fmt(1.1).unwrap(), "00001.1");
/// ```
#[inline]
pub fn width(mut self, param: usize) -> Self {
self.width = param;
self
}
/// Set the `precision` parameter.
///
/// How many digits after the decimal point are printed. Note that integers can be forced
/// to emit decimal places with this modifier.
///
/// Precision will pad or truncate as required if set. If unset, passes through as many
/// digits past the decimal as the underlying type naturally returns.
///
/// ```rust
/// # use num_runtime_fmt::{NumFmt, Dynamic};
/// assert_eq!(NumFmt::from_str(".2").unwrap().fmt(3.14159).unwrap(), "3.14");
/// assert_eq!(NumFmt::from_str(".7").unwrap().fmt(3.14159).unwrap(), "3.1415900");
/// ```
///
/// If the requested precision exceeds the native precision available to this number,
/// the remainder is always filled with `'0'`, even if `fill` is specified:
///
/// ```rust
/// # use num_runtime_fmt::NumFmt;
/// assert_eq!(NumFmt::from_str("-<6.2").unwrap().fmt(1.0_f32).unwrap(), "1.00--");
/// ```
#[inline]
pub fn precision(mut self, param: Option<usize>) -> Self {
self.precision = param;
self
}
/// Set the output format.
///
/// See [`Base`].
#[inline]
pub fn base(mut self, param: Base) -> Self {
self.format = param;
self
}
/// Set the separator.
///
/// A separator is a (typically non-numeric) character inserted between groups of digits to make
/// it easier for humans to parse the number when reading. Different separators may
/// be desirable in different contexts.
#[inline]
pub fn separator(mut self, param: Option<char>) -> Self {
self.separator = param;
self
}
/// Set the spacing.
///
/// Spacing determines the number of characters in each character group. It is only
/// of interest when the separator is set. The default spacing is 3.
#[inline]
pub fn spacing(mut self, param: usize) -> Self {
self.spacing = Some(param);
self
}
/// Set the decimal separator.
///
/// This can be desirable to i.e. support German number formats, which use a `.` to separate
/// numeric groups and a `,` as a decimal separator.
#[inline]
pub fn decimal_separator(mut self, param: char) -> Self {
self.decimal_separator = Some(param);
self
}
}
impl From<NumFmt> for Builder {
fn from(
NumFmt {
fill,
align,
sign,
hash,
zero,
width,
precision,
base: format,
separator,
spacing,
decimal_separator,
}: NumFmt,
) -> Self {
Builder {
fill,
align,
sign,
hash,
zero,
width,
precision,
format,
separator,
spacing,
decimal_separator,
}
}
}