typst/src/model/styles.rs

1144 lines
31 KiB
Rust

use std::any::Any;
use std::fmt::{self, Debug, Formatter};
use std::hash::Hash;
use std::iter;
use std::marker::PhantomData;
use std::sync::Arc;
use comemo::{Prehashed, Tracked};
use super::{capability, Args, Content, Func, NodeId, Regex, Smart, Value};
use crate::diag::SourceResult;
use crate::geom::{
Abs, Align, Axes, Corners, Em, GenAlign, Length, Numeric, PartialStroke, Rel, Sides,
};
use crate::syntax::Spanned;
use crate::util::ReadableTypeId;
use crate::World;
/// A map of style properties.
#[derive(Default, Clone, PartialEq, Hash)]
pub struct StyleMap(Vec<StyleEntry>);
impl StyleMap {
/// Create a new, empty style map.
pub fn new() -> Self {
Self::default()
}
/// Whether this map contains no styles.
pub fn is_empty(&self) -> bool {
self.0.is_empty()
}
/// Push an arbitary style entry.
pub fn push(&mut self, style: StyleEntry) {
self.0.push(style);
}
/// Create a style map from a single property-value pair.
pub fn with<'a, K: Key<'a>>(key: K, value: K::Value) -> Self {
let mut styles = Self::new();
styles.set(key, value);
styles
}
/// Set an inner value for a style property.
///
/// If the property needs folding and the value is already contained in the
/// style map, `self` contributes the outer values and `value` is the inner
/// one.
pub fn set<'a, K: Key<'a>>(&mut self, key: K, value: K::Value) {
self.push(StyleEntry::Property(Property::new(key, value)));
}
/// Set an inner value for a style property if it is `Some(_)`.
pub fn set_opt<'a, K: Key<'a>>(&mut self, key: K, value: Option<K::Value>) {
if let Some(value) = value {
self.set(key, value);
}
}
/// Whether the map contains a style property for the given key.
pub fn contains<'a, K: Key<'a>>(&self, _: K) -> bool {
self.0
.iter()
.filter_map(|entry| entry.property())
.any(|property| property.is::<K>())
}
/// Make `self` the first link of the `tail` chain.
///
/// The resulting style chain contains styles from `self` as well as
/// `tail`. The ones from `self` take precedence over the ones from
/// `tail`. For folded properties `self` contributes the inner value.
pub fn chain<'a>(&'a self, tail: &'a StyleChain<'a>) -> StyleChain<'a> {
if self.is_empty() {
*tail
} else {
StyleChain { head: &self.0, tail: Some(tail) }
}
}
/// Set an outer style property.
///
/// Like [`chain`](Self::chain) or [`apply_map`](Self::apply_map), but with
/// only a entry.
pub fn apply(&mut self, entry: StyleEntry) {
self.0.insert(0, entry);
}
/// Apply styles from `tail` in-place. The resulting style map is equivalent
/// to the style chain created by `self.chain(StyleChain::new(tail))`.
///
/// This is useful over `chain` when you want to combine two maps, but you
/// still need an owned map without a lifetime.
pub fn apply_map(&mut self, tail: &Self) {
self.0.splice(0 .. 0, tail.0.iter().cloned());
}
/// Mark all contained properties as _scoped_. This means that they only
/// apply to the first descendant node (of their type) in the hierarchy and
/// not its children, too. This is used by
/// [constructors](super::Node::construct).
pub fn scoped(mut self) -> Self {
for entry in &mut self.0 {
if let StyleEntry::Property(property) = entry {
property.make_scoped();
}
}
self
}
/// Whether this map contains styles for the given `node.`
pub fn interrupts<T: 'static>(&self) -> bool {
self.0.iter().any(|entry| entry.is_of(NodeId::of::<T>()))
}
}
impl From<StyleEntry> for StyleMap {
fn from(entry: StyleEntry) -> Self {
Self(vec![entry])
}
}
impl Debug for StyleMap {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
for entry in self.0.iter().rev() {
writeln!(f, "{:?}", entry)?;
}
Ok(())
}
}
/// An entry for a single style property, recipe or barrier.
#[derive(Clone, PartialEq, Hash)]
pub enum StyleEntry {
/// A style property originating from a set rule or constructor.
Property(Property),
/// A show rule recipe.
Recipe(Recipe),
/// A barrier for scoped styles.
Barrier(Barrier),
/// Guards against recursive show rules.
Guard(Selector),
/// Allows recursive show rules again.
Unguard(Selector),
}
impl StyleEntry {
/// Make this style the first link of the `tail` chain.
pub fn chain<'a>(&'a self, tail: &'a StyleChain) -> StyleChain<'a> {
if let StyleEntry::Barrier(barrier) = self {
if !tail
.entries()
.filter_map(StyleEntry::property)
.any(|p| p.scoped() && barrier.is_for(p.node()))
{
return *tail;
}
}
StyleChain {
head: std::slice::from_ref(self),
tail: Some(tail),
}
}
/// If this is a property, return it.
pub fn property(&self) -> Option<&Property> {
match self {
Self::Property(property) => Some(property),
_ => None,
}
}
/// If this is a recipe, return it.
pub fn recipe(&self) -> Option<&Recipe> {
match self {
Self::Recipe(recipe) => Some(recipe),
_ => None,
}
}
/// Whether this entry contains styles for the given `node.`
pub fn is_of(&self, node: NodeId) -> bool {
match self {
Self::Property(property) => property.is_of(node),
Self::Recipe(recipe) => recipe.is_of(node),
_ => false,
}
}
}
impl Debug for StyleEntry {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
f.write_str("#[")?;
match self {
Self::Property(property) => property.fmt(f)?,
Self::Recipe(recipe) => recipe.fmt(f)?,
Self::Barrier(barrier) => barrier.fmt(f)?,
Self::Guard(sel) => write!(f, "Guard against {sel:?}")?,
Self::Unguard(sel) => write!(f, "Unguard against {sel:?}")?,
}
f.write_str("]")
}
}
/// A chain of style maps, similar to a linked list.
///
/// A style chain allows to combine properties from multiple style maps in a
/// node hierarchy in a non-allocating way. Rather than eagerly merging the
/// maps, each access walks the hierarchy from the innermost to the outermost
/// map, trying to find a match and then folding it with matches further up the
/// chain.
#[derive(Default, Clone, Copy, Hash)]
pub struct StyleChain<'a> {
/// The first link of this chain.
head: &'a [StyleEntry],
/// The remaining links in the chain.
tail: Option<&'a Self>,
}
impl<'a> StyleChain<'a> {
/// Create a new, empty style chain.
pub fn new() -> Self {
Self::default()
}
/// Start a new style chain with a root map.
pub fn with_root(root: &'a StyleMap) -> Self {
Self { head: &root.0, tail: None }
}
/// Get the output value of a style property.
///
/// Returns the property's default value if no map in the chain contains an
/// entry for it. Also takes care of resolving and folding and returns
/// references where applicable.
pub fn get<K: Key<'a>>(self, key: K) -> K::Output {
K::get(self, self.values(key))
}
/// Apply show recipes in this style chain to a target.
pub fn apply(
self,
world: Tracked<dyn World>,
target: Target,
) -> SourceResult<Option<Content>> {
// Find out how many recipes there any and whether any of their patterns
// match.
let mut n = 0;
let mut any = true;
for recipe in self.entries().filter_map(StyleEntry::recipe) {
n += 1;
any |= recipe.applicable(target);
}
// Find an applicable recipe.
let mut realized = None;
let mut guarded = false;
if any {
for recipe in self.entries().filter_map(StyleEntry::recipe) {
if recipe.applicable(target) {
let sel = Selector::Nth(n);
if self.guarded(sel) {
guarded = true;
} else if let Some(content) = recipe.apply(world, sel, target)? {
realized = Some(content);
break;
}
}
n -= 1;
}
}
if let Target::Node(node) = target {
// Realize if there was no matching recipe.
if realized.is_none() {
let sel = Selector::Base(node.id());
if self.guarded(sel) {
guarded = true;
} else {
let content = node
.to::<dyn Show>()
.unwrap()
.unguard_parts(sel)
.to::<dyn Show>()
.unwrap()
.realize(world, self)?;
realized = Some(content.styled_with_entry(StyleEntry::Guard(sel)));
}
}
// Finalize only if guarding didn't stop any recipe.
if !guarded {
if let Some(content) = realized {
realized = Some(
node.to::<dyn Show>().unwrap().finalize(world, self, content)?,
);
}
}
}
Ok(realized)
}
/// Whether the recipe identified by the selector is guarded.
fn guarded(self, sel: Selector) -> bool {
for entry in self.entries() {
match *entry {
StyleEntry::Guard(s) if s == sel => return true,
StyleEntry::Unguard(s) if s == sel => return false,
_ => {}
}
}
false
}
/// Remove the last link from the chain.
fn pop(&mut self) {
*self = self.tail.copied().unwrap_or_default();
}
/// Build a style map from the suffix (all links beyond the `len`) of the
/// chain.
fn suffix(self, len: usize) -> StyleMap {
let mut suffix = StyleMap::new();
let take = self.links().count().saturating_sub(len);
for link in self.links().take(take) {
suffix.0.splice(0 .. 0, link.iter().cloned());
}
suffix
}
/// Iterate over all values for the given property in the chain.
fn values<K: Key<'a>>(self, _: K) -> Values<'a, K> {
Values {
entries: self.entries(),
depth: 0,
key: PhantomData,
}
}
/// Iterate over the entries of the chain.
fn entries(self) -> Entries<'a> {
Entries {
inner: [].as_slice().iter(),
links: self.links(),
}
}
/// Iterate over the links of the chain.
fn links(self) -> Links<'a> {
Links(Some(self))
}
}
impl Debug for StyleChain<'_> {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
for entry in self.entries() {
writeln!(f, "{:?}", entry)?;
}
Ok(())
}
}
impl PartialEq for StyleChain<'_> {
fn eq(&self, other: &Self) -> bool {
let as_ptr = |s| s as *const _;
self.head.as_ptr() == other.head.as_ptr()
&& self.head.len() == other.head.len()
&& self.tail.map(as_ptr) == other.tail.map(as_ptr)
}
}
/// An iterator over the values in a style chain.
struct Values<'a, K> {
entries: Entries<'a>,
depth: usize,
key: PhantomData<K>,
}
impl<'a, K: Key<'a>> Iterator for Values<'a, K> {
type Item = &'a K::Value;
fn next(&mut self) -> Option<Self::Item> {
for entry in &mut self.entries {
match entry {
StyleEntry::Property(property) => {
if let Some(value) = property.downcast::<K>() {
if !property.scoped() || self.depth <= 1 {
return Some(value);
}
}
}
StyleEntry::Barrier(barrier) => {
self.depth += barrier.is_for(K::node()) as usize;
}
_ => {}
}
}
None
}
}
/// An iterator over the entries in a style chain.
struct Entries<'a> {
inner: std::slice::Iter<'a, StyleEntry>,
links: Links<'a>,
}
impl<'a> Iterator for Entries<'a> {
type Item = &'a StyleEntry;
fn next(&mut self) -> Option<Self::Item> {
loop {
if let Some(entry) = self.inner.next_back() {
return Some(entry);
}
match self.links.next() {
Some(next) => self.inner = next.iter(),
None => return None,
}
}
}
}
/// An iterator over the links of a style chain.
struct Links<'a>(Option<StyleChain<'a>>);
impl<'a> Iterator for Links<'a> {
type Item = &'a [StyleEntry];
fn next(&mut self) -> Option<Self::Item> {
let StyleChain { head, tail } = self.0?;
self.0 = tail.copied();
Some(head)
}
}
/// A sequence of items with associated styles.
#[derive(Hash)]
pub struct StyleVec<T> {
items: Vec<T>,
maps: Vec<(StyleMap, usize)>,
}
impl<T> StyleVec<T> {
/// Whether there are any items in the sequence.
pub fn is_empty(&self) -> bool {
self.items.is_empty()
}
/// Number of items in the sequence.
pub fn len(&self) -> usize {
self.items.len()
}
/// Insert an element in the front. The element will share the style of the
/// current first element.
///
/// This method has no effect if the vector is empty.
pub fn push_front(&mut self, item: T) {
if !self.maps.is_empty() {
self.items.insert(0, item);
self.maps[0].1 += 1;
}
}
/// Map the contained items.
pub fn map<F, U>(&self, f: F) -> StyleVec<U>
where
F: FnMut(&T) -> U,
{
StyleVec {
items: self.items.iter().map(f).collect(),
maps: self.maps.clone(),
}
}
/// Iterate over references to the contained items and associated style maps.
pub fn iter(&self) -> impl Iterator<Item = (&T, &StyleMap)> + '_ {
self.items().zip(
self.maps
.iter()
.flat_map(|(map, count)| iter::repeat(map).take(*count)),
)
}
/// Iterate over the contained items.
pub fn items(&self) -> std::slice::Iter<'_, T> {
self.items.iter()
}
/// Iterate over the contained maps. Note that zipping this with `items()`
/// does not yield the same result as calling `iter()` because this method
/// only returns maps once that are shared by consecutive items. This method
/// is designed for use cases where you want to check, for example, whether
/// any of the maps fulfills a specific property.
pub fn styles(&self) -> impl Iterator<Item = &StyleMap> {
self.maps.iter().map(|(map, _)| map)
}
}
impl<T> Default for StyleVec<T> {
fn default() -> Self {
Self { items: vec![], maps: vec![] }
}
}
impl<T> FromIterator<T> for StyleVec<T> {
fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Self {
let items: Vec<_> = iter.into_iter().collect();
let maps = vec![(StyleMap::new(), items.len())];
Self { items, maps }
}
}
impl<T: Debug> Debug for StyleVec<T> {
fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
f.debug_list()
.entries(self.iter().map(|(item, map)| {
crate::util::debug(|f| {
map.fmt(f)?;
item.fmt(f)
})
}))
.finish()
}
}
/// Assists in the construction of a [`StyleVec`].
pub struct StyleVecBuilder<'a, T> {
items: Vec<T>,
chains: Vec<(StyleChain<'a>, usize)>,
}
impl<'a, T> StyleVecBuilder<'a, T> {
/// Create a new style-vec builder.
pub fn new() -> Self {
Self { items: vec![], chains: vec![] }
}
/// Whether the builder is empty.
pub fn is_empty(&self) -> bool {
self.items.is_empty()
}
/// Push a new item into the style vector.
pub fn push(&mut self, item: T, styles: StyleChain<'a>) {
self.items.push(item);
if let Some((prev, count)) = self.chains.last_mut() {
if *prev == styles {
*count += 1;
return;
}
}
self.chains.push((styles, 1));
}
/// Iterate over the contained items.
pub fn items(&self) -> std::slice::Iter<'_, T> {
self.items.iter()
}
/// Finish building, returning a pair of two things:
/// - a style vector of items with the non-shared styles
/// - a shared prefix chain of styles that apply to all items
pub fn finish(self) -> (StyleVec<T>, StyleChain<'a>) {
let mut iter = self.chains.iter();
let mut trunk = match iter.next() {
Some(&(chain, _)) => chain,
None => return Default::default(),
};
let mut shared = trunk.links().count();
for &(mut chain, _) in iter {
let len = chain.links().count();
if len < shared {
for _ in 0 .. shared - len {
trunk.pop();
}
shared = len;
} else if len > shared {
for _ in 0 .. len - shared {
chain.pop();
}
}
while shared > 0 && chain != trunk {
trunk.pop();
chain.pop();
shared -= 1;
}
}
let maps = self
.chains
.into_iter()
.map(|(chain, count)| (chain.suffix(shared), count))
.collect();
(StyleVec { items: self.items, maps }, trunk)
}
}
impl<'a, T> Default for StyleVecBuilder<'a, T> {
fn default() -> Self {
Self::new()
}
}
/// A style property originating from a set rule or constructor.
#[derive(Clone, Hash)]
pub struct Property {
/// The id of the property's [key](Key).
key: KeyId,
/// The id of the node the property belongs to.
node: NodeId,
/// Whether the property should only affect the first node down the
/// hierarchy. Used by constructors.
scoped: bool,
/// The property's value.
value: Arc<Prehashed<dyn Bounds>>,
/// The name of the property.
#[cfg(debug_assertions)]
name: &'static str,
}
impl Property {
/// Create a new property from a key-value pair.
pub fn new<'a, K: Key<'a>>(_: K, value: K::Value) -> Self {
Self {
key: KeyId::of::<K>(),
node: K::node(),
value: Arc::new(Prehashed::new(value)),
scoped: false,
#[cfg(debug_assertions)]
name: K::NAME,
}
}
/// Whether this property has the given key.
pub fn is<'a, K: Key<'a>>(&self) -> bool {
self.key == KeyId::of::<K>()
}
/// Whether this property belongs to the node with the given id.
pub fn is_of(&self, node: NodeId) -> bool {
self.node == node
}
/// Access the property's value if it is of the given key.
pub fn downcast<'a, K: Key<'a>>(&'a self) -> Option<&'a K::Value> {
if self.key == KeyId::of::<K>() {
(**self.value).as_any().downcast_ref()
} else {
None
}
}
/// The node this property is for.
pub fn node(&self) -> NodeId {
self.node
}
/// Whether the property is scoped.
pub fn scoped(&self) -> bool {
self.scoped
}
/// Make the property scoped.
pub fn make_scoped(&mut self) {
self.scoped = true;
}
}
impl Debug for Property {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
#[cfg(debug_assertions)]
write!(f, "{} = ", self.name)?;
write!(f, "{:?}", self.value)?;
if self.scoped {
write!(f, " [scoped]")?;
}
Ok(())
}
}
impl PartialEq for Property {
fn eq(&self, other: &Self) -> bool {
self.key == other.key
&& self.value.eq(&other.value)
&& self.scoped == other.scoped
}
}
trait Bounds: Debug + Sync + Send + 'static {
fn as_any(&self) -> &dyn Any;
}
impl<T> Bounds for T
where
T: Debug + Sync + Send + 'static,
{
fn as_any(&self) -> &dyn Any {
self
}
}
/// A style property key.
///
/// This trait is not intended to be implemented manually, but rather through
/// the `#[node]` proc-macro.
pub trait Key<'a>: Copy + 'static {
/// The unfolded type which this property is stored as in a style map.
type Value: Debug + Clone + Hash + Sync + Send + 'static;
/// The folded type of value that is returned when reading this property
/// from a style chain.
type Output;
/// The name of the property, used for debug printing.
const NAME: &'static str;
/// The id of the node the key belongs to.
fn node() -> NodeId;
/// Compute an output value from a sequence of values belonging to this key,
/// folding if necessary.
fn get(
chain: StyleChain<'a>,
values: impl Iterator<Item = &'a Self::Value>,
) -> Self::Output;
}
/// A unique identifier for a property key.
#[derive(Copy, Clone, Eq, PartialEq, Hash)]
struct KeyId(ReadableTypeId);
impl KeyId {
/// The id of the given key.
pub fn of<'a, T: Key<'a>>() -> Self {
Self(ReadableTypeId::of::<T>())
}
}
impl Debug for KeyId {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
self.0.fmt(f)
}
}
/// A scoped property barrier.
///
/// Barriers interact with [scoped](super::StyleMap::scoped) styles: A scoped
/// style can still be read through a single barrier (the one of the node it
/// _should_ apply to), but a second barrier will make it invisible.
#[derive(Copy, Clone, Eq, PartialEq, Hash)]
pub struct Barrier(NodeId);
impl Barrier {
/// Create a new barrier for the given node.
pub fn new(node: NodeId) -> Self {
Self(node)
}
/// Whether this barrier is for the node `T`.
pub fn is_for(&self, node: NodeId) -> bool {
self.0 == node
}
}
impl Debug for Barrier {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(f, "Barrier for {:?}", self.0)
}
}
/// A property that is resolved with other properties from the style chain.
pub trait Resolve {
/// The type of the resolved output.
type Output;
/// Resolve the value using the style chain.
fn resolve(self, styles: StyleChain) -> Self::Output;
}
impl Resolve for Em {
type Output = Abs;
fn resolve(self, styles: StyleChain) -> Self::Output {
if self.is_zero() {
Abs::zero()
} else {
self.at(item!(em)(styles))
}
}
}
impl Resolve for Length {
type Output = Abs;
fn resolve(self, styles: StyleChain) -> Self::Output {
self.abs + self.em.resolve(styles)
}
}
impl<T: Resolve> Resolve for Option<T> {
type Output = Option<T::Output>;
fn resolve(self, styles: StyleChain) -> Self::Output {
self.map(|v| v.resolve(styles))
}
}
impl<T: Resolve> Resolve for Smart<T> {
type Output = Smart<T::Output>;
fn resolve(self, styles: StyleChain) -> Self::Output {
self.map(|v| v.resolve(styles))
}
}
impl<T: Resolve> Resolve for Axes<T> {
type Output = Axes<T::Output>;
fn resolve(self, styles: StyleChain) -> Self::Output {
self.map(|v| v.resolve(styles))
}
}
impl<T: Resolve> Resolve for Sides<T> {
type Output = Sides<T::Output>;
fn resolve(self, styles: StyleChain) -> Self::Output {
self.map(|v| v.resolve(styles))
}
}
impl<T: Resolve> Resolve for Corners<T> {
type Output = Corners<T::Output>;
fn resolve(self, styles: StyleChain) -> Self::Output {
self.map(|v| v.resolve(styles))
}
}
impl<T> Resolve for Rel<T>
where
T: Resolve + Numeric,
<T as Resolve>::Output: Numeric,
{
type Output = Rel<<T as Resolve>::Output>;
fn resolve(self, styles: StyleChain) -> Self::Output {
self.map(|abs| abs.resolve(styles))
}
}
impl Resolve for GenAlign {
type Output = Align;
fn resolve(self, styles: StyleChain) -> Self::Output {
let dir = item!(dir)(styles);
match self {
Self::Start => dir.start().into(),
Self::End => dir.end().into(),
Self::Specific(align) => align,
}
}
}
impl Resolve for PartialStroke {
type Output = PartialStroke<Abs>;
fn resolve(self, styles: StyleChain) -> Self::Output {
PartialStroke {
paint: self.paint,
thickness: self.thickness.resolve(styles),
}
}
}
/// A property that is folded to determine its final value.
pub trait Fold {
/// The type of the folded output.
type Output;
/// Fold this inner value with an outer folded value.
fn fold(self, outer: Self::Output) -> Self::Output;
}
impl<T> Fold for Option<T>
where
T: Fold,
T::Output: Default,
{
type Output = Option<T::Output>;
fn fold(self, outer: Self::Output) -> Self::Output {
self.map(|inner| inner.fold(outer.unwrap_or_default()))
}
}
impl<T> Fold for Smart<T>
where
T: Fold,
T::Output: Default,
{
type Output = Smart<T::Output>;
fn fold(self, outer: Self::Output) -> Self::Output {
self.map(|inner| inner.fold(outer.unwrap_or_default()))
}
}
impl<T> Fold for Sides<T>
where
T: Fold,
{
type Output = Sides<T::Output>;
fn fold(self, outer: Self::Output) -> Self::Output {
self.zip(outer, |inner, outer| inner.fold(outer))
}
}
impl Fold for Sides<Option<Rel<Abs>>> {
type Output = Sides<Rel<Abs>>;
fn fold(self, outer: Self::Output) -> Self::Output {
self.zip(outer, |inner, outer| inner.unwrap_or(outer))
}
}
impl Fold for Sides<Option<Smart<Rel<Length>>>> {
type Output = Sides<Smart<Rel<Length>>>;
fn fold(self, outer: Self::Output) -> Self::Output {
self.zip(outer, |inner, outer| inner.unwrap_or(outer))
}
}
impl<T> Fold for Corners<T>
where
T: Fold,
{
type Output = Corners<T::Output>;
fn fold(self, outer: Self::Output) -> Self::Output {
self.zip(outer, |inner, outer| inner.fold(outer))
}
}
impl Fold for Corners<Option<Rel<Abs>>> {
type Output = Corners<Rel<Abs>>;
fn fold(self, outer: Self::Output) -> Self::Output {
self.zip(outer, |inner, outer| inner.unwrap_or(outer))
}
}
impl Fold for PartialStroke<Abs> {
type Output = Self;
fn fold(self, outer: Self::Output) -> Self::Output {
Self {
paint: self.paint.or(outer.paint),
thickness: self.thickness.or(outer.thickness),
}
}
}
/// A show rule recipe.
#[derive(Clone, PartialEq, Hash)]
pub struct Recipe {
/// The patterns to customize.
pub pattern: Pattern,
/// The function that defines the recipe.
pub func: Spanned<Func>,
}
impl Recipe {
/// Whether the recipe is applicable to the target.
pub fn applicable(&self, target: Target) -> bool {
match (&self.pattern, target) {
(Pattern::Node(id), Target::Node(node)) => *id == node.id(),
(Pattern::Regex(_), Target::Text(_)) => true,
_ => false,
}
}
/// Try to apply the recipe to the target.
pub fn apply(
&self,
world: Tracked<dyn World>,
sel: Selector,
target: Target,
) -> SourceResult<Option<Content>> {
let content = match (target, &self.pattern) {
(Target::Node(node), &Pattern::Node(id)) if node.id() == id => {
let node = node.to::<dyn Show>().unwrap().unguard_parts(sel);
self.call(world, || Value::Content(node))?
}
(Target::Text(text), Pattern::Regex(regex)) => {
let make = world.config().items.text;
let mut result = vec![];
let mut cursor = 0;
for mat in regex.find_iter(text) {
let start = mat.start();
if cursor < start {
result.push(make(text[cursor .. start].into()));
}
result.push(self.call(world, || Value::Str(mat.as_str().into()))?);
cursor = mat.end();
}
if result.is_empty() {
return Ok(None);
}
if cursor < text.len() {
result.push(make(text[cursor ..].into()));
}
Content::sequence(result)
}
_ => return Ok(None),
};
Ok(Some(content.styled_with_entry(StyleEntry::Guard(sel))))
}
/// Call the recipe function, with the argument if desired.
fn call<F>(&self, world: Tracked<dyn World>, arg: F) -> SourceResult<Content>
where
F: FnOnce() -> Value,
{
let args = if self.func.v.argc() == Some(0) {
Args::new(self.func.span, [])
} else {
Args::new(self.func.span, [arg()])
};
Ok(self.func.v.call_detached(world, args)?.display(world))
}
/// Whether this recipe is for the given node.
pub fn is_of(&self, node: NodeId) -> bool {
match self.pattern {
Pattern::Node(id) => id == node,
_ => false,
}
}
}
impl Debug for Recipe {
fn fmt(&self, f: &mut Formatter) -> fmt::Result {
write!(
f,
"Recipe matching {:?} from {:?}",
self.pattern, self.func.span
)
}
}
/// A show rule pattern that may match a target.
#[derive(Debug, Clone, PartialEq, Hash)]
pub enum Pattern {
/// Defines the appearence of some node.
Node(NodeId),
/// Defines text to be replaced.
Regex(Regex),
}
impl Pattern {
/// Define a simple text replacement pattern.
pub fn text(text: &str) -> Self {
Self::Regex(Regex::new(&regex::escape(text)).unwrap())
}
}
/// A target for a show rule recipe.
#[derive(Debug, Copy, Clone, PartialEq)]
pub enum Target<'a> {
/// A showable node.
Node(&'a Content),
/// A slice of text.
Text(&'a str),
}
/// Identifies a show rule recipe.
#[derive(Debug, Copy, Clone, PartialEq, Hash)]
pub enum Selector {
/// The nth recipe from the top of the chain.
Nth(usize),
/// The base recipe for a kind of node.
Base(NodeId),
}
/// A node that can be realized given some styles.
#[capability]
pub trait Show: 'static + Sync + Send {
/// Unguard nested content against recursive show rules.
fn unguard_parts(&self, sel: Selector) -> Content;
/// Access a field on this node.
fn field(&self, name: &str) -> Option<Value>;
/// The base recipe for this node that is executed if there is no
/// user-defined show rule.
fn realize(
&self,
world: Tracked<dyn World>,
styles: StyleChain,
) -> SourceResult<Content>;
/// Finalize this node given the realization of a base or user recipe. Use
/// this for effects that should work even in the face of a user-defined
/// show rule, for example:
/// - Application of general settable properties
///
/// Defaults to just the realized content.
#[allow(unused_variables)]
fn finalize(
&self,
world: Tracked<dyn World>,
styles: StyleChain,
realized: Content,
) -> SourceResult<Content> {
Ok(realized)
}
}