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use std::fmt::{self, Display, Formatter};
use std::marker::PhantomData;
use toddle::query::{FontStyle, FontWeight};
use crate::layout::prelude::*;
use crate::size::{Size, ScaleSize};
use crate::style::Paper;
use super::*;
use self::AlignmentValue::*;
pub trait Value {
type Output;
fn parse(expr: Spanned<Expr>) -> Result<Self::Output, Error>;
}
impl<V: Value> Value for Spanned<V> {
type Output = Spanned<V::Output>;
fn parse(expr: Spanned<Expr>) -> Result<Self::Output, Error> {
let span = expr.span;
V::parse(expr).map(|v| Spanned { v, span })
}
}
macro_rules! value {
($type:ty, $output:ty, $name:expr, $($p:pat => $r:expr),* $(,)?) => {
impl Value for $type {
type Output = $output;
fn parse(expr: Spanned<Expr>) -> Result<Self::Output, Error> {
#[allow(unreachable_patterns)]
match expr.v {
$($p => Ok($r)),*,
other => Err(err!("expected {}, found {}",
$name, other.name())),
}
}
}
};
}
value!(Expr, Self, "expression", e => e);
value!(Ident, Self, "identifier", Expr::Ident(i) => i);
value!(String, Self, "string", Expr::Str(s) => s);
value!(f64, Self, "number", Expr::Number(n) => n);
value!(bool, Self, "bool", Expr::Bool(b) => b);
value!(Size, Self, "size", Expr::Size(s) => s);
value!(Tuple, Self, "tuple", Expr::Tuple(t) => t);
value!(Object, Self, "object", Expr::Object(o) => o);
value!(ScaleSize, Self, "number or size",
Expr::Size(size) => ScaleSize::Absolute(size),
Expr::Number(scale) => ScaleSize::Scaled(scale as f32),
);
pub struct StringLike;
value!(StringLike, String, "identifier or string",
Expr::Ident(Ident(s)) => s,
Expr::Str(s) => s,
);
pub struct Defaultable<T>(PhantomData<T>);
impl<T: Value> Value for Defaultable<T> {
type Output = Option<T::Output>;
fn parse(expr: Spanned<Expr>) -> Result<Self::Output, Error> {
match expr.v {
Expr::Ident(ident) if ident.as_str() == "default" => Ok(None),
_ => T::parse(expr).map(Some)
}
}
}
impl Value for FontStyle {
type Output = Self;
fn parse(expr: Spanned<Expr>) -> Result<Self::Output, Error> {
FontStyle::from_str(Ident::parse(expr)?.as_str())
.ok_or_else(|| err!("invalid font style"))
}
}
impl Value for FontWeight {
type Output = (Self, bool);
fn parse(expr: Spanned<Expr>) -> Result<Self::Output, Error> {
match expr.v {
Expr::Number(weight) => {
let weight = weight.round();
if weight >= 100.0 && weight <= 900.0 {
Ok((FontWeight(weight as i16), false))
} else {
let clamped = weight.min(900.0).max(100.0) as i16;
Ok((FontWeight(clamped), true))
}
}
Expr::Ident(id) => {
FontWeight::from_str(id.as_str())
.ok_or_else(|| err!("invalid font weight"))
.map(|weight| (weight, false))
}
other => Err(err!("expected identifier or number, \
found {}", other.name())),
}
}
}
impl Value for Paper {
type Output = Self;
fn parse(expr: Spanned<Expr>) -> Result<Self::Output, Error> {
Paper::from_str(Ident::parse(expr)?.as_str())
.ok_or_else(|| err!("invalid paper type"))
}
}
impl Value for Direction {
type Output = Self;
fn parse(expr: Spanned<Expr>) -> Result<Self::Output, Error> {
Ok(match Ident::parse(expr)?.as_str() {
"left-to-right" | "ltr" | "LTR" => LeftToRight,
"right-to-left" | "rtl" | "RTL" => RightToLeft,
"top-to-bottom" | "ttb" | "TTB" => TopToBottom,
"bottom-to-top" | "btt" | "BTT" => BottomToTop,
_ => return Err(err!("invalid direction"))
})
}
}
#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
pub enum AlignmentValue {
Align(Alignment),
Left,
Top,
Right,
Bottom,
}
impl AlignmentValue {
/// The generic axis this alignment corresponds to in the given system of
/// layouting axes. `None` if the alignment is generic.
pub fn axis(self, axes: LayoutAxes) -> Option<GenericAxis> {
match self {
Left | Right => Some(Horizontal.to_generic(axes)),
Top | Bottom => Some(Vertical.to_generic(axes)),
Align(_) => None,
}
}
/// The generic version of this alignment in the given system of layouting
/// axes.
///
/// Returns `None` if the alignment is invalid for the given axis.
pub fn to_generic(self, axes: LayoutAxes, axis: GenericAxis) -> Option<Alignment> {
let specific = axis.to_specific(axes);
let start = match axes.get(axis).is_positive() {
true => Origin,
false => End,
};
match (self, specific) {
(Align(alignment), _) => Some(alignment),
(Left, Horizontal) | (Top, Vertical) => Some(start),
(Right, Horizontal) | (Bottom, Vertical) => Some(start.inv()),
_ => None
}
}
/// The specific version of this alignment in the given system of layouting
/// axes.
pub fn to_specific(self, axes: LayoutAxes, axis: SpecificAxis) -> AlignmentValue {
let direction = axes.get_specific(axis);
if let Align(alignment) = self {
match (direction, alignment) {
(LeftToRight, Origin) | (RightToLeft, End) => Left,
(LeftToRight, End) | (RightToLeft, Origin) => Right,
(TopToBottom, Origin) | (BottomToTop, End) => Top,
(TopToBottom, End) | (BottomToTop, Origin) => Bottom,
(_, Center) => self,
}
} else {
self
}
}
}
impl Value for AlignmentValue {
type Output = Self;
fn parse(expr: Spanned<Expr>) -> Result<Self::Output, Error> {
Ok(match Ident::parse(expr)?.as_str() {
"origin" => Align(Origin),
"center" => Align(Center),
"end" => Align(End),
"left" => Left,
"top" => Top,
"right" => Right,
"bottom" => Bottom,
_ => return Err(err!("invalid alignment"))
})
}
}
impl Display for AlignmentValue {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
match self {
Align(Origin) => write!(f, "origin"),
Align(Center) => write!(f, "center"),
Align(End) => write!(f, "end"),
Left => write!(f, "left"),
Top => write!(f, "top"),
Right => write!(f, "right"),
Bottom => write!(f, "bottom"),
}
}
}
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