Split crates

1 files changed, 0 insertions, 814 deletions

diff --git a/src/library/layout/mod.rs b/src/library/layout/mod.rs
deleted file mode 100644
index 000cb212..00000000
--- a/src/library/layout/mod.rs
+++ /dev/null
@@ -1,814 +0,0 @@
-//! Composable layouts.
-
-mod align;
-mod columns;
-mod container;
-mod flow;
-mod grid;
-mod pad;
-mod page;
-mod place;
-mod spacing;
-mod stack;
-mod transform;
-
-pub use align::*;
-pub use columns::*;
-pub use container::*;
-pub use flow::*;
-pub use grid::*;
-pub use pad::*;
-pub use page::*;
-pub use place::*;
-pub use spacing::*;
-pub use stack::*;
-pub use transform::*;
-
-use std::mem;
-
-use comemo::Tracked;
-use typed_arena::Arena;
-
-use crate::diag::SourceResult;
-use crate::frame::Frame;
-use crate::geom::*;
-use crate::library::structure::{DocNode, ListItem, ListNode, DESC, ENUM, LIST};
-use crate::library::text::{
-    LinebreakNode, ParChild, ParNode, ParbreakNode, SmartQuoteNode, SpaceNode, TextNode,
-};
-use crate::model::{
-    capability, Barrier, Content, Interruption, Node, SequenceNode, Show, StyleChain,
-    StyleEntry, StyleMap, StyleVec, StyleVecBuilder, StyledNode, Target,
-};
-use crate::World;
-
-/// The root-level layout.
-#[capability]
-pub trait Layout: 'static + Sync + Send {
-    /// Layout into one frame per page.
-    fn layout(&self, world: Tracked<dyn World>) -> SourceResult<Vec<Frame>>;
-}
-
-impl Layout for Content {
-    #[comemo::memoize]
-    fn layout(&self, world: Tracked<dyn World>) -> SourceResult<Vec<Frame>> {
-        let styles = StyleChain::with_root(&world.config().styles);
-        let scratch = Scratch::default();
-
-        let mut builder = Builder::new(world, &scratch, true);
-        builder.accept(self, styles)?;
-
-        let (doc, shared) = builder.into_doc(styles)?;
-        doc.layout(world, shared)
-    }
-}
-
-/// Block-level layout.
-#[capability]
-pub trait LayoutBlock: 'static + Sync + Send {
-    /// Layout into one frame per region.
-    fn layout_block(
-        &self,
-        world: Tracked<dyn World>,
-        regions: &Regions,
-        styles: StyleChain,
-    ) -> SourceResult<Vec<Frame>>;
-}
-
-impl LayoutBlock for Content {
-    #[comemo::memoize]
-    fn layout_block(
-        &self,
-        world: Tracked<dyn World>,
-        regions: &Regions,
-        styles: StyleChain,
-    ) -> SourceResult<Vec<Frame>> {
-        if let Some(node) = self.to::<dyn LayoutBlock>() {
-            let barrier = StyleEntry::Barrier(Barrier::new(self.id()));
-            let styles = barrier.chain(&styles);
-            return node.layout_block(world, regions, styles);
-        }
-
-        let scratch = Scratch::default();
-        let mut builder = Builder::new(world, &scratch, false);
-        builder.accept(self, styles)?;
-        let (flow, shared) = builder.into_flow(styles)?;
-        flow.layout_block(world, regions, shared)
-    }
-}
-
-/// Inline-level layout.
-#[capability]
-pub trait LayoutInline: 'static + Sync + Send {
-    /// Layout into a single frame.
-    fn layout_inline(
-        &self,
-        world: Tracked<dyn World>,
-        regions: &Regions,
-        styles: StyleChain,
-    ) -> SourceResult<Vec<Frame>>;
-}
-
-impl LayoutInline for Content {
-    #[comemo::memoize]
-    fn layout_inline(
-        &self,
-        world: Tracked<dyn World>,
-        regions: &Regions,
-        styles: StyleChain,
-    ) -> SourceResult<Vec<Frame>> {
-        if let Some(node) = self.to::<dyn LayoutInline>() {
-            let barrier = StyleEntry::Barrier(Barrier::new(self.id()));
-            let styles = barrier.chain(&styles);
-            return node.layout_inline(world, regions, styles);
-        }
-
-        if let Some(node) = self.to::<dyn LayoutBlock>() {
-            let barrier = StyleEntry::Barrier(Barrier::new(self.id()));
-            let styles = barrier.chain(&styles);
-            return node.layout_block(world, regions, styles);
-        }
-
-        let scratch = Scratch::default();
-        let mut builder = Builder::new(world, &scratch, false);
-        builder.accept(self, styles)?;
-        let (flow, shared) = builder.into_flow(styles)?;
-        flow.layout_block(world, regions, shared)
-    }
-}
-
-/// A sequence of regions to layout into.
-#[derive(Debug, Clone, Hash)]
-pub struct Regions {
-    /// The (remaining) size of the first region.
-    pub first: Size,
-    /// The base size for relative sizing.
-    pub base: Size,
-    /// The height of followup regions. The width is the same for all regions.
-    pub backlog: Vec<Abs>,
-    /// The height of the final region that is repeated once the backlog is
-    /// drained. The width is the same for all regions.
-    pub last: Option<Abs>,
-    /// Whether nodes should expand to fill the regions instead of shrinking to
-    /// fit the content.
-    pub expand: Axes<bool>,
-}
-
-impl Regions {
-    /// Create a new region sequence with exactly one region.
-    pub fn one(size: Size, base: Size, expand: Axes<bool>) -> Self {
-        Self {
-            first: size,
-            base,
-            backlog: vec![],
-            last: None,
-            expand,
-        }
-    }
-
-    /// Create a new sequence of same-size regions that repeats indefinitely.
-    pub fn repeat(size: Size, base: Size, expand: Axes<bool>) -> Self {
-        Self {
-            first: size,
-            base,
-            backlog: vec![],
-            last: Some(size.y),
-            expand,
-        }
-    }
-
-    /// Create new regions where all sizes are mapped with `f`.
-    ///
-    /// Note that since all regions must have the same width, the width returned
-    /// by `f` is ignored for the backlog and the final region.
-    pub fn map<F>(&self, mut f: F) -> Self
-    where
-        F: FnMut(Size) -> Size,
-    {
-        let x = self.first.x;
-        Self {
-            first: f(self.first),
-            base: f(self.base),
-            backlog: self.backlog.iter().map(|&y| f(Size::new(x, y)).y).collect(),
-            last: self.last.map(|y| f(Size::new(x, y)).y),
-            expand: self.expand,
-        }
-    }
-
-    /// Whether the first region is full and a region break is called for.
-    pub fn is_full(&self) -> bool {
-        Abs::zero().fits(self.first.y) && !self.in_last()
-    }
-
-    /// Whether the first region is the last usable region.
-    ///
-    /// If this is true, calling `next()` will have no effect.
-    pub fn in_last(&self) -> bool {
-        self.backlog.len() == 0 && self.last.map_or(true, |height| self.first.y == height)
-    }
-
-    /// Advance to the next region if there is any.
-    pub fn next(&mut self) {
-        if let Some(height) = (!self.backlog.is_empty())
-            .then(|| self.backlog.remove(0))
-            .or(self.last)
-        {
-            self.first.y = height;
-            self.base.y = height;
-        }
-    }
-
-    /// An iterator that returns the sizes of the first and all following
-    /// regions, equivalently to what would be produced by calling
-    /// [`next()`](Self::next) repeatedly until all regions are exhausted.
-    /// This iterater may be infinite.
-    pub fn iter(&self) -> impl Iterator<Item = Size> + '_ {
-        let first = std::iter::once(self.first);
-        let backlog = self.backlog.iter();
-        let last = self.last.iter().cycle();
-        first.chain(backlog.chain(last).map(|&h| Size::new(self.first.x, h)))
-    }
-}
-
-/// Builds a document or a flow node from content.
-struct Builder<'a> {
-    /// The core context.
-    world: Tracked<'a, dyn World>,
-    /// Scratch arenas for building.
-    scratch: &'a Scratch<'a>,
-    /// The current document building state.
-    doc: Option<DocBuilder<'a>>,
-    /// The current flow building state.
-    flow: FlowBuilder<'a>,
-    /// The current paragraph building state.
-    par: ParBuilder<'a>,
-    /// The current list building state.
-    list: ListBuilder<'a>,
-}
-
-/// Temporary storage arenas for building.
-#[derive(Default)]
-struct Scratch<'a> {
-    /// An arena where intermediate style chains are stored.
-    styles: Arena<StyleChain<'a>>,
-    /// An arena where intermediate content resulting from show rules is stored.
-    templates: Arena<Content>,
-}
-
-impl<'a> Builder<'a> {
-    pub fn new(
-        world: Tracked<'a, dyn World>,
-        scratch: &'a Scratch<'a>,
-        top: bool,
-    ) -> Self {
-        Self {
-            world,
-            scratch,
-            doc: top.then(|| DocBuilder::default()),
-            flow: FlowBuilder::default(),
-            par: ParBuilder::default(),
-            list: ListBuilder::default(),
-        }
-    }
-
-    pub fn into_doc(
-        mut self,
-        styles: StyleChain<'a>,
-    ) -> SourceResult<(DocNode, StyleChain<'a>)> {
-        self.interrupt(Interruption::Page, styles, true)?;
-        let (pages, shared) = self.doc.unwrap().pages.finish();
-        Ok((DocNode(pages), shared))
-    }
-
-    pub fn into_flow(
-        mut self,
-        styles: StyleChain<'a>,
-    ) -> SourceResult<(FlowNode, StyleChain<'a>)> {
-        self.interrupt(Interruption::Par, styles, false)?;
-        let (children, shared) = self.flow.0.finish();
-        Ok((FlowNode(children), shared))
-    }
-
-    pub fn accept(
-        &mut self,
-        content: &'a Content,
-        styles: StyleChain<'a>,
-    ) -> SourceResult<()> {
-        if let Some(text) = content.downcast::<TextNode>() {
-            if let Some(realized) = styles.apply(self.world, Target::Text(&text.0))? {
-                let stored = self.scratch.templates.alloc(realized);
-                return self.accept(stored, styles);
-            }
-        } else if let Some(styled) = content.downcast::<StyledNode>() {
-            return self.styled(styled, styles);
-        } else if let Some(seq) = content.downcast::<SequenceNode>() {
-            return self.sequence(seq, styles);
-        } else if content.has::<dyn Show>() {
-            if self.show(&content, styles)? {
-                return Ok(());
-            }
-        }
-
-        if self.list.accept(content, styles) {
-            return Ok(());
-        }
-
-        self.interrupt(Interruption::List, styles, false)?;
-
-        if content.is::<ListItem>() {
-            self.list.accept(content, styles);
-            return Ok(());
-        }
-
-        if self.par.accept(content, styles) {
-            return Ok(());
-        }
-
-        self.interrupt(Interruption::Par, styles, false)?;
-
-        if self.flow.accept(content, styles) {
-            return Ok(());
-        }
-
-        let keep = content
-            .downcast::<PagebreakNode>()
-            .map_or(false, |pagebreak| !pagebreak.weak);
-        self.interrupt(Interruption::Page, styles, keep)?;
-
-        if let Some(doc) = &mut self.doc {
-            doc.accept(content, styles);
-        }
-
-        // We might want to issue a warning or error for content that wasn't
-        // handled (e.g. a pagebreak in a flow building process). However, we
-        // don't have the spans here at the moment.
-        Ok(())
-    }
-
-    fn show(
-        &mut self,
-        content: &'a Content,
-        styles: StyleChain<'a>,
-    ) -> SourceResult<bool> {
-        if let Some(mut realized) = styles.apply(self.world, Target::Node(content))? {
-            let mut map = StyleMap::new();
-            let barrier = Barrier::new(content.id());
-            map.push(StyleEntry::Barrier(barrier));
-            map.push(StyleEntry::Barrier(barrier));
-            realized = realized.styled_with_map(map);
-            let stored = self.scratch.templates.alloc(realized);
-            self.accept(stored, styles)?;
-            Ok(true)
-        } else {
-            Ok(false)
-        }
-    }
-
-    fn styled(
-        &mut self,
-        styled: &'a StyledNode,
-        styles: StyleChain<'a>,
-    ) -> SourceResult<()> {
-        let stored = self.scratch.styles.alloc(styles);
-        let styles = styled.map.chain(stored);
-        let intr = styled.map.interruption();
-
-        if let Some(intr) = intr {
-            self.interrupt(intr, styles, false)?;
-        }
-
-        self.accept(&styled.sub, styles)?;
-
-        if let Some(intr) = intr {
-            self.interrupt(intr, styles, true)?;
-        }
-
-        Ok(())
-    }
-
-    fn interrupt(
-        &mut self,
-        intr: Interruption,
-        styles: StyleChain<'a>,
-        keep: bool,
-    ) -> SourceResult<()> {
-        if intr >= Interruption::List && !self.list.is_empty() {
-            mem::take(&mut self.list).finish(self)?;
-        }
-
-        if intr >= Interruption::Par {
-            if !self.par.is_empty() {
-                mem::take(&mut self.par).finish(self);
-            }
-        }
-
-        if intr >= Interruption::Page {
-            if let Some(doc) = &mut self.doc {
-                if !self.flow.is_empty() || (doc.keep_next && keep) {
-                    mem::take(&mut self.flow).finish(doc, styles);
-                }
-                doc.keep_next = !keep;
-            }
-        }
-
-        Ok(())
-    }
-
-    fn sequence(
-        &mut self,
-        seq: &'a SequenceNode,
-        styles: StyleChain<'a>,
-    ) -> SourceResult<()> {
-        for content in &seq.0 {
-            self.accept(content, styles)?;
-        }
-        Ok(())
-    }
-}
-
-/// Accepts pagebreaks and pages.
-struct DocBuilder<'a> {
-    /// The page runs built so far.
-    pages: StyleVecBuilder<'a, PageNode>,
-    /// Whether to keep a following page even if it is empty.
-    keep_next: bool,
-}
-
-impl<'a> DocBuilder<'a> {
-    fn accept(&mut self, content: &'a Content, styles: StyleChain<'a>) {
-        if let Some(pagebreak) = content.downcast::<PagebreakNode>() {
-            self.keep_next = !pagebreak.weak;
-        }
-
-        if let Some(page) = content.downcast::<PageNode>() {
-            self.pages.push(page.clone(), styles);
-            self.keep_next = false;
-        }
-    }
-}
-
-impl Default for DocBuilder<'_> {
-    fn default() -> Self {
-        Self {
-            pages: StyleVecBuilder::new(),
-            keep_next: true,
-        }
-    }
-}
-
-/// Accepts flow content.
-#[derive(Default)]
-struct FlowBuilder<'a>(CollapsingBuilder<'a, FlowChild>);
-
-impl<'a> FlowBuilder<'a> {
-    fn accept(&mut self, content: &'a Content, styles: StyleChain<'a>) -> bool {
-        // Weak flow elements:
-        // Weakness | Element
-        //    0     | weak colbreak
-        //    1     | weak fractional spacing
-        //    2     | weak spacing
-        //    3     | generated weak spacing
-        //    4     | generated weak fractional spacing
-        //    5     | par spacing
-
-        if let Some(_) = content.downcast::<ParbreakNode>() {
-            /* Nothing to do */
-        } else if let Some(colbreak) = content.downcast::<ColbreakNode>() {
-            if colbreak.weak {
-                self.0.weak(FlowChild::Colbreak, styles, 0);
-            } else {
-                self.0.destructive(FlowChild::Colbreak, styles);
-            }
-        } else if let Some(vertical) = content.downcast::<VNode>() {
-            let child = FlowChild::Spacing(vertical.amount);
-            let frac = vertical.amount.is_fractional();
-            if vertical.weak {
-                let weakness = 1 + u8::from(frac) + 2 * u8::from(vertical.generated);
-                self.0.weak(child, styles, weakness);
-            } else if frac {
-                self.0.destructive(child, styles);
-            } else {
-                self.0.ignorant(child, styles);
-            }
-        } else if content.has::<dyn LayoutBlock>() {
-            let child = FlowChild::Block(content.clone());
-            if content.is::<PlaceNode>() {
-                self.0.ignorant(child, styles);
-            } else {
-                self.0.supportive(child, styles);
-            }
-        } else {
-            return false;
-        }
-
-        true
-    }
-
-    fn par(&mut self, par: ParNode, styles: StyleChain<'a>, indent: bool) {
-        let amount = if indent && !styles.get(ParNode::SPACING_AND_INDENT) {
-            styles.get(ParNode::LEADING).into()
-        } else {
-            styles.get(ParNode::SPACING).into()
-        };
-
-        self.0.weak(FlowChild::Spacing(amount), styles, 5);
-        self.0.supportive(FlowChild::Block(par.pack()), styles);
-        self.0.weak(FlowChild::Spacing(amount), styles, 5);
-    }
-
-    fn finish(self, doc: &mut DocBuilder<'a>, styles: StyleChain<'a>) {
-        let (flow, shared) = self.0.finish();
-        let styles = if flow.is_empty() { styles } else { shared };
-        let node = PageNode(FlowNode(flow).pack());
-        doc.pages.push(node, styles);
-    }
-
-    fn is_empty(&self) -> bool {
-        self.0.is_empty()
-    }
-}
-
-/// Accepts paragraph content.
-#[derive(Default)]
-struct ParBuilder<'a>(CollapsingBuilder<'a, ParChild>);
-
-impl<'a> ParBuilder<'a> {
-    fn accept(&mut self, content: &'a Content, styles: StyleChain<'a>) -> bool {
-        // Weak par elements:
-        // Weakness | Element
-        //    0     | weak fractional spacing
-        //    1     | weak spacing
-        //    2     | space
-
-        if content.is::<SpaceNode>() {
-            self.0.weak(ParChild::Text(' '.into()), styles, 2);
-        } else if let Some(linebreak) = content.downcast::<LinebreakNode>() {
-            let c = if linebreak.justify { '\u{2028}' } else { '\n' };
-            self.0.destructive(ParChild::Text(c.into()), styles);
-        } else if let Some(horizontal) = content.downcast::<HNode>() {
-            let child = ParChild::Spacing(horizontal.amount);
-            let frac = horizontal.amount.is_fractional();
-            if horizontal.weak {
-                let weakness = u8::from(!frac);
-                self.0.weak(child, styles, weakness);
-            } else if frac {
-                self.0.destructive(child, styles);
-            } else {
-                self.0.ignorant(child, styles);
-            }
-        } else if let Some(quote) = content.downcast::<SmartQuoteNode>() {
-            self.0.supportive(ParChild::Quote { double: quote.double }, styles);
-        } else if let Some(text) = content.downcast::<TextNode>() {
-            self.0.supportive(ParChild::Text(text.0.clone()), styles);
-        } else if content.has::<dyn LayoutInline>() {
-            self.0.supportive(ParChild::Inline(content.clone()), styles);
-        } else {
-            return false;
-        }
-
-        true
-    }
-
-    fn finish(self, parent: &mut Builder<'a>) {
-        let (mut children, shared) = self.0.finish();
-        if children.is_empty() {
-            return;
-        }
-
-        // Paragraph indent should only apply if the paragraph starts with
-        // text and follows directly after another paragraph.
-        let indent = shared.get(ParNode::INDENT);
-        if !indent.is_zero()
-            && children
-                .items()
-                .find_map(|child| match child {
-                    ParChild::Spacing(_) => None,
-                    ParChild::Text(_) | ParChild::Quote { .. } => Some(true),
-                    ParChild::Inline(_) => Some(false),
-                })
-                .unwrap_or_default()
-            && parent
-                .flow
-                .0
-                .items()
-                .rev()
-                .find_map(|child| match child {
-                    FlowChild::Spacing(_) => None,
-                    FlowChild::Block(content) => Some(content.is::<ParNode>()),
-                    FlowChild::Colbreak => Some(false),
-                })
-                .unwrap_or_default()
-        {
-            children.push_front(ParChild::Spacing(indent.into()));
-        }
-
-        parent.flow.par(ParNode(children), shared, !indent.is_zero());
-    }
-
-    fn is_empty(&self) -> bool {
-        self.0.is_empty()
-    }
-}
-
-/// Accepts list / enum items, spaces, paragraph breaks.
-struct ListBuilder<'a> {
-    /// The list items collected so far.
-    items: StyleVecBuilder<'a, ListItem>,
-    /// Whether the list contains no paragraph breaks.
-    tight: bool,
-    /// Whether the list can be attached.
-    attachable: bool,
-    /// Trailing content for which it is unclear whether it is part of the list.
-    staged: Vec<(&'a Content, StyleChain<'a>)>,
-}
-
-impl<'a> ListBuilder<'a> {
-    fn accept(&mut self, content: &'a Content, styles: StyleChain<'a>) -> bool {
-        if self.items.is_empty() {
-            if content.is::<ParbreakNode>() {
-                self.attachable = false;
-            } else if !content.is::<SpaceNode>() && !content.is::<ListItem>() {
-                self.attachable = true;
-            }
-        }
-
-        if let Some(item) = content.downcast::<ListItem>() {
-            if self
-                .items
-                .items()
-                .next()
-                .map_or(true, |first| item.kind() == first.kind())
-            {
-                self.items.push(item.clone(), styles);
-                self.tight &= self.staged.drain(..).all(|(t, _)| !t.is::<ParbreakNode>());
-            } else {
-                return false;
-            }
-        } else if !self.items.is_empty()
-            && (content.is::<SpaceNode>() || content.is::<ParbreakNode>())
-        {
-            self.staged.push((content, styles));
-        } else {
-            return false;
-        }
-
-        true
-    }
-
-    fn finish(self, parent: &mut Builder<'a>) -> SourceResult<()> {
-        let (items, shared) = self.items.finish();
-        let kind = match items.items().next() {
-            Some(item) => item.kind(),
-            None => return Ok(()),
-        };
-
-        let tight = self.tight;
-        let attached = tight && self.attachable;
-        let content = match kind {
-            LIST => ListNode::<LIST> { tight, attached, items }.pack(),
-            ENUM => ListNode::<ENUM> { tight, attached, items }.pack(),
-            DESC | _ => ListNode::<DESC> { tight, attached, items }.pack(),
-        };
-
-        let stored = parent.scratch.templates.alloc(content);
-        parent.accept(stored, shared)?;
-
-        for (content, styles) in self.staged {
-            parent.accept(content, styles)?;
-        }
-
-        parent.list.attachable = true;
-
-        Ok(())
-    }
-
-    fn is_empty(&self) -> bool {
-        self.items.is_empty()
-    }
-}
-
-impl Default for ListBuilder<'_> {
-    fn default() -> Self {
-        Self {
-            items: StyleVecBuilder::default(),
-            tight: true,
-            attachable: true,
-            staged: vec![],
-        }
-    }
-}
-
-/// A wrapper around a [`StyleVecBuilder`] that allows to collapse items.
-struct CollapsingBuilder<'a, T> {
-    /// The internal builder.
-    builder: StyleVecBuilder<'a, T>,
-    /// Staged weak and ignorant items that we can't yet commit to the builder.
-    /// The option is `Some(_)` for weak items and `None` for ignorant items.
-    staged: Vec<(T, StyleChain<'a>, Option<u8>)>,
-    /// What the last non-ignorant item was.
-    last: Last,
-}
-
-/// What the last non-ignorant item was.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-enum Last {
-    Weak,
-    Destructive,
-    Supportive,
-}
-
-impl<'a, T> CollapsingBuilder<'a, T> {
-    /// Create a new style-vec builder.
-    pub fn new() -> Self {
-        Self {
-            builder: StyleVecBuilder::new(),
-            staged: vec![],
-            last: Last::Destructive,
-        }
-    }
-
-    /// Whether the builder is empty.
-    pub fn is_empty(&self) -> bool {
-        self.builder.is_empty() && self.staged.is_empty()
-    }
-
-    /// Can only exist when there is at least one supportive item to its left
-    /// and to its right, with no destructive items in between. There may be
-    /// ignorant items in between in both directions.
-    ///
-    /// Between weak items, there may be at least one per layer and among the
-    /// candidates the strongest one (smallest `weakness`) wins. When tied,
-    /// the one that compares larger through `PartialOrd` wins.
-    pub fn weak(&mut self, item: T, styles: StyleChain<'a>, weakness: u8)
-    where
-        T: PartialOrd,
-    {
-        if self.last == Last::Destructive {
-            return;
-        }
-
-        if self.last == Last::Weak {
-            if let Some(i) =
-                self.staged.iter().position(|(prev_item, _, prev_weakness)| {
-                    prev_weakness.map_or(false, |prev_weakness| {
-                        weakness < prev_weakness
-                            || (weakness == prev_weakness && item > *prev_item)
-                    })
-                })
-            {
-                self.staged.remove(i);
-            } else {
-                return;
-            }
-        }
-
-        self.staged.push((item, styles, Some(weakness)));
-        self.last = Last::Weak;
-    }
-
-    /// Forces nearby weak items to collapse.
-    pub fn destructive(&mut self, item: T, styles: StyleChain<'a>) {
-        self.flush(false);
-        self.builder.push(item, styles);
-        self.last = Last::Destructive;
-    }
-
-    /// Allows nearby weak items to exist.
-    pub fn supportive(&mut self, item: T, styles: StyleChain<'a>) {
-        self.flush(true);
-        self.builder.push(item, styles);
-        self.last = Last::Supportive;
-    }
-
-    /// Has no influence on other items.
-    pub fn ignorant(&mut self, item: T, styles: StyleChain<'a>) {
-        self.staged.push((item, styles, None));
-    }
-
-    /// Iterate over the contained items.
-    pub fn items(&self) -> impl DoubleEndedIterator<Item = &T> {
-        self.builder.items().chain(self.staged.iter().map(|(item, ..)| item))
-    }
-
-    /// Return the finish style vec and the common prefix chain.
-    pub fn finish(mut self) -> (StyleVec<T>, StyleChain<'a>) {
-        self.flush(false);
-        self.builder.finish()
-    }
-
-    /// Push the staged items, filtering out weak items if `supportive` is
-    /// false.
-    fn flush(&mut self, supportive: bool) {
-        for (item, styles, meta) in self.staged.drain(..) {
-            if supportive || meta.is_none() {
-                self.builder.push(item, styles);
-            }
-        }
-    }
-}
-
-impl<'a, T> Default for CollapsingBuilder<'a, T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}