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|
use crate::diag::bail;
use crate::foundations::{cast, elem, func, Content, NativeElement, SymbolElem};
use crate::layout::{Length, Rel};
use crate::math::Mathy;
/// Attaches an accent to a base.
///
/// # Example
/// ```example
/// $grave(a) = accent(a, `)$ \
/// $arrow(a) = accent(a, arrow)$ \
/// $tilde(a) = accent(a, \u{0303})$
/// ```
#[elem(Mathy)]
pub struct AccentElem {
/// The base to which the accent is applied. May consist of multiple
/// letters.
///
/// ```example
/// $arrow(A B C)$
/// ```
#[required]
pub base: Content,
/// The accent to apply to the base.
///
/// Supported accents include:
///
/// | Accent | Name | Codepoint |
/// | ------------- | --------------- | --------- |
/// | Grave | `grave` | <code>`</code> |
/// | Acute | `acute` | `´` |
/// | Circumflex | `hat` | `^` |
/// | Tilde | `tilde` | `~` |
/// | Macron | `macron` | `¯` |
/// | Dash | `dash` | `‾` |
/// | Breve | `breve` | `˘` |
/// | Dot | `dot` | `.` |
/// | Double dot, Diaeresis | `dot.double`, `diaer` | `¨` |
/// | Triple dot | `dot.triple` | <code>⃛</code> |
/// | Quadruple dot | `dot.quad` | <code>⃜</code> |
/// | Circle | `circle` | `∘` |
/// | Double acute | `acute.double` | `˝` |
/// | Caron | `caron` | `ˇ` |
/// | Right arrow | `arrow`, `->` | `→` |
/// | Left arrow | `arrow.l`, `<-` | `←` |
/// | Left/Right arrow | `arrow.l.r` | `↔` |
/// | Right harpoon | `harpoon` | `⇀` |
/// | Left harpoon | `harpoon.lt` | `↼` |
#[required]
pub accent: Accent,
/// The size of the accent, relative to the width of the base.
///
/// ```example
/// $dash(A, size: #150%)$
/// ```
#[resolve]
#[default(Rel::one())]
pub size: Rel<Length>,
/// Whether to remove the dot on top of lowercase i and j when adding a top
/// accent.
///
/// This enables the `dtls` OpenType feature.
///
/// ```example
/// $hat(dotless: #false, i)$
/// ```
#[default(true)]
pub dotless: bool,
}
/// An accent character.
#[derive(Debug, Default, Copy, Clone, Eq, PartialEq, Hash)]
pub struct Accent(pub char);
impl Accent {
/// Normalize a character into an accent.
pub fn new(c: char) -> Self {
Self(Self::combine(c).unwrap_or(c))
}
/// List of bottom accents. Currently just a list of ones included in the
/// Unicode math class document.
const BOTTOM: &[char] = &[
'\u{0323}', '\u{032C}', '\u{032D}', '\u{032E}', '\u{032F}', '\u{0330}',
'\u{0331}', '\u{0332}', '\u{0333}', '\u{033A}', '\u{20E8}', '\u{20EC}',
'\u{20ED}', '\u{20EE}', '\u{20EF}',
];
/// Whether this accent is a bottom accent or not.
pub fn is_bottom(&self) -> bool {
Self::BOTTOM.contains(&self.0)
}
}
/// This macro generates accent-related functions.
///
/// ```ignore
/// accents! {
/// '\u{0300}' | '`' => grave,
/// // ^^^^^^^^^ ^^^ ^^^^^
/// // | | |
/// // | | +-- The name of the function.
/// // | +--------- The alternative characters that represent the accent.
/// // +---------------------- The primary character that represents the accent.
/// }
/// ```
///
/// When combined with the `Accent::combine` function, accent characters can be normalized
/// to the primary character.
macro_rules! accents {
($($primary:literal $(| $alt:literal)* => $name:ident),* $(,)?) => {
impl Accent {
/// Normalize an accent to a combining one.
pub fn combine(c: char) -> Option<char> {
Some(match c {
$($primary $(| $alt)* => $primary,)*
_ => return None,
})
}
}
$(
/// The accent function for callable symbol definitions.
#[func]
pub fn $name(
/// The base to which the accent is applied.
base: Content,
/// The size of the accent, relative to the width of the base.
#[named]
size: Option<Rel<Length>>,
/// Whether to remove the dot on top of lowercase i and j when
/// adding a top accent.
#[named]
dotless: Option<bool>,
) -> Content {
let mut accent = AccentElem::new(base, Accent::new($primary));
if let Some(size) = size {
accent = accent.with_size(size);
}
if let Some(dotless) = dotless {
accent = accent.with_dotless(dotless);
}
accent.pack()
}
)+
};
}
// Keep it synced with the documenting table above.
accents! {
'\u{0300}' | '`' => grave,
'\u{0301}' | '´' => acute,
'\u{0302}' | '^' | 'ˆ' => hat,
'\u{0303}' | '~' | '∼' | '˜' => tilde,
'\u{0304}' | '¯' => macron,
'\u{0305}' | '-' | '‾' | '−' => dash,
'\u{0306}' | '˘' => breve,
'\u{0307}' | '.' | '˙' | '⋅' => dot,
'\u{0308}' | '¨' => dot_double,
'\u{20db}' => dot_triple,
'\u{20dc}' => dot_quad,
'\u{030a}' | '∘' | '○' => circle,
'\u{030b}' | '˝' => acute_double,
'\u{030c}' | 'ˇ' => caron,
'\u{20d6}' | '←' => arrow_l,
'\u{20d7}' | '→' | '⟶' => arrow,
'\u{20e1}' | '↔' | '⟷' => arrow_l_r,
'\u{20d0}' | '↼' => harpoon_lt,
'\u{20d1}' | '⇀' => harpoon,
}
cast! {
Accent,
self => self.0.into_value(),
v: char => Self::new(v),
v: Content => match v.to_packed::<SymbolElem>() {
Some(elem) => Self::new(elem.text),
None => bail!("expected a symbol"),
},
}
|
