Extract `model` module

1 files changed, 0 insertions, 829 deletions

diff --git a/src/eval/styles.rs b/src/eval/styles.rs
deleted file mode 100644
index b666c85d..00000000
--- a/src/eval/styles.rs
+++ /dev/null
@@ -1,829 +0,0 @@
-use std::any::{Any, TypeId};
-use std::fmt::{self, Debug, Formatter};
-use std::hash::Hash;
-use std::marker::PhantomData;
-use std::sync::Arc;
-
-use super::{Args, Content, Func, Layout, Node, Show, ShowNode, Smart, Span, Value};
-use crate::diag::{At, TypResult};
-use crate::geom::{Numeric, Relative, Sides, Spec};
-use crate::library::layout::PageNode;
-use crate::library::text::{FontFamily, ParNode, TextNode};
-use crate::util::Prehashed;
-use crate::Context;
-
-/// A map of style properties.
-#[derive(Default, Clone, PartialEq, Hash)]
-pub struct StyleMap(Vec<Entry>);
-
-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()
-    }
-
-    /// 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.0.push(Entry::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);
-        }
-    }
-
-    /// Set a font family composed of a preferred family and existing families
-    /// from a style chain.
-    pub fn set_family(&mut self, preferred: FontFamily, existing: StyleChain) {
-        self.set(
-            TextNode::FAMILY,
-            std::iter::once(preferred)
-                .chain(existing.get(TextNode::FAMILY).iter().cloned())
-                .collect(),
-        );
-    }
-
-    /// Set a show rule recipe for a node.
-    pub fn set_recipe<T: Node>(&mut self, func: Func, span: Span) {
-        self.0.push(Entry::Recipe(Recipe::new::<T>(func, span)));
-    }
-
-    /// 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.key == TypeId::of::<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 value for a style property.
-    ///
-    /// If the property needs folding and the value is already contained in the
-    /// style map, `self` contributes the inner values and `value` is the outer
-    /// one.
-    ///
-    /// Like [`chain`](Self::chain) or [`apply_map`](Self::apply_map), but with
-    /// only a single property.
-    pub fn apply<'a, K: Key<'a>>(&mut self, key: K, value: K::Value) {
-        self.0.insert(0, Entry::Property(Property::new(key, value)));
-    }
-
-    /// 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](Node::construct).
-    pub fn scoped(mut self) -> Self {
-        for entry in &mut self.0 {
-            if let Entry::Property(property) = entry {
-                property.scoped = true;
-            }
-        }
-        self
-    }
-
-    /// The highest-level kind of of structure the map interrupts.
-    pub fn interruption(&self) -> Option<Interruption> {
-        self.0
-            .iter()
-            .filter_map(|entry| entry.property())
-            .filter_map(|property| property.interruption())
-            .max()
-    }
-}
-
-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)]
-enum Entry {
-    /// A style property originating from a set rule or constructor.
-    Property(Property),
-    /// A barrier for scoped styles.
-    Barrier(TypeId, &'static str),
-    /// A show rule recipe.
-    Recipe(Recipe),
-}
-
-impl Entry {
-    /// If this is a property, return it.
-    fn property(&self) -> Option<&Property> {
-        match self {
-            Self::Property(property) => Some(property),
-            _ => None,
-        }
-    }
-
-    /// If this is a recipe, return it.
-    fn recipe(&self) -> Option<&Recipe> {
-        match self {
-            Self::Recipe(recipe) => Some(recipe),
-            _ => None,
-        }
-    }
-}
-
-impl Debug for Entry {
-    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(_, name) => write!(f, "Barrier for {name}")?,
-        }
-        f.write_str("]")
-    }
-}
-
-/// A style property originating from a set rule or constructor.
-#[derive(Clone, Hash)]
-struct Property {
-    /// The type id of the property's [key](Key).
-    key: TypeId,
-    /// The type id of the node the property belongs to.
-    node: TypeId,
-    /// The name of the property.
-    name: &'static str,
-    /// The property's value.
-    value: Arc<Prehashed<dyn Bounds>>,
-    /// Whether the property should only affects the first node down the
-    /// hierarchy. Used by constructors.
-    scoped: bool,
-}
-
-impl Property {
-    /// Create a new property from a key-value pair.
-    fn new<'a, K: Key<'a>>(_: K, value: K::Value) -> Self {
-        Self {
-            key: TypeId::of::<K>(),
-            node: K::node(),
-            name: K::NAME,
-            value: Arc::new(Prehashed::new(value)),
-            scoped: false,
-        }
-    }
-
-    /// What kind of structure the property interrupts.
-    fn interruption(&self) -> Option<Interruption> {
-        if self.is_of::<PageNode>() {
-            Some(Interruption::Page)
-        } else if self.is_of::<ParNode>() {
-            Some(Interruption::Par)
-        } else {
-            None
-        }
-    }
-
-    /// Access the property's value if it is of the given key.
-    fn downcast<'a, K: Key<'a>>(&'a self) -> Option<&'a K::Value> {
-        if self.key == TypeId::of::<K>() {
-            (**self.value).as_any().downcast_ref()
-        } else {
-            None
-        }
-    }
-
-    /// Whether this property belongs to the node `T`.
-    fn is_of<T: Node>(&self) -> bool {
-        self.node == TypeId::of::<T>()
-    }
-}
-
-impl Debug for Property {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "{} = {:?}", self.name, 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
-    }
-}
-
-/// Style property keys.
-///
-/// 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. For
-    /// example, this is [`Toggle`](crate::geom::Length) for the
-    /// [`STRONG`](TextNode::STRONG) property.
-    type Value: Debug + Clone + Hash + Sync + Send + 'static;
-
-    /// The folded type of value that is returned when reading this property
-    /// from a style chain. For example, this is [`bool`] for the
-    /// [`STRONG`](TextNode::STRONG) property. For non-copy, non-folding
-    /// properties this is a reference type.
-    type Output;
-
-    /// The name of the property, used for debug printing.
-    const NAME: &'static str;
-
-    /// The type id of the node this property belongs to.
-    fn node() -> TypeId;
-
-    /// Compute an output value from a sequence of values belong to this key,
-    /// folding if necessary.
-    fn get(
-        chain: StyleChain<'a>,
-        values: impl Iterator<Item = &'a Self::Value>,
-    ) -> Self::Output;
-}
-
-/// 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<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 Spec<T> {
-    type Output = Spec<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 {
-        Sides {
-            left: self.left.resolve(styles),
-            right: self.right.resolve(styles),
-            top: self.top.resolve(styles),
-            bottom: self.bottom.resolve(styles),
-        }
-    }
-}
-
-impl<T> Resolve for Relative<T>
-where
-    T: Resolve + Numeric,
-    <T as Resolve>::Output: Numeric,
-{
-    type Output = Relative<<T as Resolve>::Output>;
-
-    fn resolve(self, styles: StyleChain) -> Self::Output {
-        self.map(|abs| abs.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()))
-    }
-}
-
-/// A show rule recipe.
-#[derive(Clone, PartialEq, Hash)]
-struct Recipe {
-    /// The affected node.
-    node: TypeId,
-    /// The name of the affected node.
-    name: &'static str,
-    /// The function that defines the recipe.
-    func: Func,
-    /// The span to report all erros with.
-    span: Span,
-}
-
-impl Recipe {
-    /// Create a new recipe for the node `T`.
-    fn new<T: Node>(func: Func, span: Span) -> Self {
-        Self {
-            node: TypeId::of::<T>(),
-            name: std::any::type_name::<T>(),
-            func,
-            span,
-        }
-    }
-}
-
-impl Debug for Recipe {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        write!(f, "Recipe for {} from {:?}", self.name, self.span)
-    }
-}
-
-/// A style chain barrier.
-///
-/// Barriers interact with [scoped](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(Clone, PartialEq, Hash)]
-pub struct Barrier(Entry);
-
-impl Barrier {
-    /// Create a new barrier for the layout node `T`.
-    pub fn new<T: Layout>() -> Self {
-        Self(Entry::Barrier(
-            TypeId::of::<T>(),
-            std::any::type_name::<T>(),
-        ))
-    }
-
-    /// Make this barrier the first link of the `tail` chain.
-    pub fn chain<'a>(&'a self, tail: &'a StyleChain) -> StyleChain<'a> {
-        // We have to store a full `Entry` enum inside the barrier because
-        // otherwise the `slice::from_ref` trick below won't work.
-        // Unfortunately, that also means we have to somehow extract the id
-        // here.
-        let id = match self.0 {
-            Entry::Barrier(id, _) => id,
-            _ => unreachable!(),
-        };
-
-        if tail
-            .entries()
-            .filter_map(Entry::property)
-            .any(|p| p.scoped && p.node == id)
-        {
-            StyleChain {
-                head: std::slice::from_ref(&self.0),
-                tail: Some(tail),
-            }
-        } else {
-            *tail
-        }
-    }
-}
-
-impl Debug for Barrier {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        self.0.fmt(f)
-    }
-}
-
-/// Determines whether a style could interrupt some composable structure.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Ord, PartialOrd)]
-pub enum Interruption {
-    /// The style forces a paragraph break.
-    Par,
-    /// The style forces a page break.
-    Page,
-}
-
-/// 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 [Entry],
-    /// 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))
-    }
-
-    /// Realize a node with a user recipe.
-    pub fn realize(
-        self,
-        ctx: &mut Context,
-        node: &ShowNode,
-    ) -> TypResult<Option<Content>> {
-        let id = node.id();
-        if let Some(recipe) = self
-            .entries()
-            .filter_map(Entry::recipe)
-            .find(|recipe| recipe.node == id)
-        {
-            let dict = node.encode();
-            let args = Args::from_values(recipe.span, [Value::Dict(dict)]);
-            Ok(Some(recipe.func.call(ctx, args)?.cast().at(recipe.span)?))
-        } else {
-            Ok(None)
-        }
-    }
-}
-
-impl<'a> StyleChain<'a> {
-    /// Return the chain, but without the trailing scoped property for the given
-    /// `node`. This is a 90% hack fix for show node constructor scoping.
-    pub(super) fn unscoped(mut self, node: TypeId) -> Self {
-        while self
-            .head
-            .last()
-            .and_then(Entry::property)
-            .map_or(false, |p| p.scoped && p.node == node)
-        {
-            let len = self.head.len();
-            self.head = &self.head[.. len - 1]
-        }
-        self
-    }
-
-    /// 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> {
-        while let Some(entry) = self.entries.next() {
-            match entry {
-                Entry::Property(property) => {
-                    if let Some(value) = property.downcast::<K>() {
-                        if !property.scoped || self.depth <= 1 {
-                            return Some(value);
-                        }
-                    }
-                }
-                Entry::Barrier(id, _) => {
-                    self.depth += (*id == K::node()) as usize;
-                }
-                Entry::Recipe(_) => {}
-            }
-        }
-
-        None
-    }
-}
-
-/// An iterator over the entries in a style chain.
-struct Entries<'a> {
-    inner: std::slice::Iter<'a, Entry>,
-    links: Links<'a>,
-}
-
-impl<'a> Iterator for Entries<'a> {
-    type Item = &'a Entry;
-
-    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 [Entry];
-
-    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()
-    }
-
-    /// 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 maps(&self) -> impl Iterator<Item = &StyleMap> {
-        self.maps.iter().map(|(map, _)| map)
-    }
-
-    /// Iterate over the contained items.
-    pub fn items(&self) -> std::slice::Iter<'_, T> {
-        self.items.iter()
-    }
-
-    /// Iterate over the contained items and associated style maps.
-    pub fn iter(&self) -> impl Iterator<Item = (&T, &StyleMap)> + '_ {
-        let styles = self
-            .maps
-            .iter()
-            .flat_map(|(map, count)| std::iter::repeat(map).take(*count));
-        self.items().zip(styles)
-    }
-
-    /// 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;
-        }
-    }
-}
-
-impl<T> Default for StyleVec<T> {
-    fn default() -> Self {
-        Self { items: vec![], maps: vec![] }
-    }
-}
-
-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![] }
-    }
-
-    /// 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));
-    }
-
-    /// Access the last item mutably and its chain by value.
-    pub fn last_mut(&mut self) -> Option<(&mut T, StyleChain<'a>)> {
-        let item = self.items.last_mut()?;
-        let chain = self.chains.last()?.0;
-        Some((item, chain))
-    }
-
-    /// 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()
-    }
-}