Tidying

21 files changed, 312 insertions, 285 deletions

diff --git a/src/eval/ops.rs b/src/eval/ops.rs
index 23530c10..94e57718 100644
--- a/src/eval/ops.rs
+++ b/src/eval/ops.rs
@@ -94,10 +94,6 @@ pub fn add(lhs: Value, rhs: Value) -> StrResult<Value> {
                 if let (Some(&a), Some(&b)) =
                     (a.downcast::<Align>(), b.downcast::<Align>())
                 {
-                    dynamic! {
-                        Spec<Align>: "2d alignment",
-                    }
-
                     return if a.axis() != b.axis() {
                         Ok(Dyn(Dynamic::new(match a.axis() {
                             SpecAxis::Horizontal => Spec { x: a, y: b },
diff --git a/src/library/align.rs b/src/library/align.rs
index c16277f6..16c44905 100644
--- a/src/library/align.rs
+++ b/src/library/align.rs
@@ -1,9 +1,11 @@
+//! Aligning nodes in their parent container.
+
 use super::prelude::*;
 use super::ParNode;
 
 /// `align`: Configure the alignment along the layouting axes.
 pub fn align(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    let aligns: Spec<_> = args.expect("alignment")?;
+    let aligns: Spec<_> = args.find().unwrap_or_default();
     let body: Node = args.expect("body")?;
 
     let mut styles = Styles::new();
@@ -16,6 +18,26 @@ pub fn align(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     ))
 }
 
+dynamic! {
+    Align: "alignment",
+}
+
+dynamic! {
+    Spec<Align>: "2d alignment",
+}
+
+castable! {
+    Spec<Option<Align>>,
+    Expected: "1d or 2d alignment",
+    @align: Align => {
+        let mut aligns = Spec::default();
+        aligns.set(align.axis(), Some(*align));
+        aligns
+    },
+    @aligns: Spec<Align> => aligns.map(Some),
+
+}
+
 /// A node that aligns its child.
 #[derive(Debug, Hash)]
 pub struct AlignNode {
@@ -57,19 +79,3 @@ impl Layout for AlignNode {
         frames
     }
 }
-
-dynamic! {
-    Align: "alignment",
-}
-
-castable! {
-    Spec<Option<Align>>,
-    Expected: "1d or 2d alignment",
-    @align: Align => {
-        let mut aligns = Spec::default();
-        aligns.set(align.axis(), Some(*align));
-        aligns
-    },
-    @aligns: Spec<Align> => aligns.map(Some),
-
-}
diff --git a/src/library/columns.rs b/src/library/columns.rs
index 25d6da9d..df55fb52 100644
--- a/src/library/columns.rs
+++ b/src/library/columns.rs
@@ -1,7 +1,9 @@
+//! Multi-column layouts.
+
 use super::prelude::*;
 use super::ParNode;
 
-/// `columns`: Stack children along an axis.
+/// `columns`: Set content into multiple columns.
 pub fn columns(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     let columns = args.expect("column count")?;
     let gutter = args.named("gutter")?.unwrap_or(Relative::new(0.04).into());
@@ -36,6 +38,8 @@ impl Layout for ColumnsNode {
         ctx: &mut LayoutContext,
         regions: &Regions,
     ) -> Vec<Constrained<Rc<Frame>>> {
+        let columns = self.columns.get();
+
         // Separating the infinite space into infinite columns does not make
         // much sense. Note that this line assumes that no infinitely wide
         // region will follow if the first region's width is finite.
@@ -51,21 +55,15 @@ impl Layout for ColumnsNode {
         // `region.backlog` and `regions.last`.
         let mut sizes = vec![];
 
-        let columns = self.columns.get();
-
         for (current, base) in regions
             .iter()
-            .take(1 + regions.backlog.len() + if regions.last.is_some() { 1 } else { 0 })
+            .take(1 + regions.backlog.len() + regions.last.iter().len())
         {
             let gutter = self.gutter.resolve(base.x);
+            let width = (current.x - gutter * (columns - 1) as f64) / columns as f64;
+            let size = Size::new(width, current.y);
             gutters.push(gutter);
-            let size = Size::new(
-                (current.x - gutter * (columns - 1) as f64) / columns as f64,
-                current.y,
-            );
-            for _ in 0 .. columns {
-                sizes.push(size);
-            }
+            sizes.extend(std::iter::repeat(size).take(columns));
         }
 
         let first = sizes.remove(0);
@@ -76,24 +74,22 @@ impl Layout for ColumnsNode {
         );
 
         // Retrieve elements for the last region from the vectors.
-        let last_gutter = if regions.last.is_some() {
+        let last_gutter = regions.last.map(|_| {
             let gutter = gutters.pop().unwrap();
             let size = sizes.drain(sizes.len() - columns ..).next().unwrap();
             pod.last = Some(size);
-            Some(gutter)
-        } else {
-            None
-        };
+            gutter
+        });
 
         pod.backlog = sizes.into_iter();
 
+        let mut finished = vec![];
         let mut frames = self.child.layout(ctx, &pod).into_iter();
 
         let dir = ctx.styles.get(ParNode::DIR);
-
-        let mut finished = vec![];
         let total_regions = (frames.len() as f32 / columns as f32).ceil() as usize;
 
+        // Stitch together the columns for each region.
         for ((current, base), gutter) in regions
             .iter()
             .take(total_regions)
@@ -103,41 +99,35 @@ impl Layout for ColumnsNode {
             // Otherwise its the maximum column height for the frame. In that
             // case, the frame is first created with zero height and then
             // resized.
-            let mut height = if regions.expand.y { current.y } else { Length::zero() };
-            let mut frame = Frame::new(Spec::new(regions.current.x, height));
-
+            let height = if regions.expand.y { current.y } else { Length::zero() };
+            let mut output = Frame::new(Spec::new(regions.current.x, height));
             let mut cursor = Length::zero();
 
             for _ in 0 .. columns {
-                let child_frame = match frames.next() {
+                let frame = match frames.next() {
                     Some(frame) => frame.item,
                     None => break,
                 };
 
-                let width = child_frame.size.x;
-
                 if !regions.expand.y {
-                    height.set_max(child_frame.size.y);
+                    output.size.y.set_max(frame.size.y);
                 }
 
-                frame.push_frame(
-                    Point::with_x(if dir.is_positive() {
-                        cursor
-                    } else {
-                        regions.current.x - cursor - width
-                    }),
-                    child_frame,
-                );
+                let width = frame.size.x;
+                let x = if dir.is_positive() {
+                    cursor
+                } else {
+                    regions.current.x - cursor - width
+                };
 
+                output.push_frame(Point::with_x(x), frame);
                 cursor += width + gutter;
             }
 
-            frame.size.y = height;
-
             let mut cts = Constraints::new(regions.expand);
             cts.base = base.map(Some);
             cts.exact = current.map(Some);
-            finished.push(frame.constrain(cts));
+            finished.push(output.constrain(cts));
         }
 
         finished
diff --git a/src/library/flow.rs b/src/library/flow.rs
index 6bfa3ddd..810e566a 100644
--- a/src/library/flow.rs
+++ b/src/library/flow.rs
@@ -1,3 +1,5 @@
+//! A flow of paragraphs and other block-level nodes.
+
 use std::fmt::{self, Debug, Formatter};
 
 use super::prelude::*;
diff --git a/src/library/grid.rs b/src/library/grid.rs
index d341cf5b..3292cfe0 100644
--- a/src/library/grid.rs
+++ b/src/library/grid.rs
@@ -1,47 +1,20 @@
+//! Layout along a row and column raster.
+
 use super::prelude::*;
 
 /// `grid`: Arrange children into a grid.
 pub fn grid(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    castable! {
-        Vec<TrackSizing>,
-        Expected: "integer or (auto, linear, fractional, or array thereof)",
-        Value::Auto => vec![TrackSizing::Auto],
-        Value::Length(v) => vec![TrackSizing::Linear(v.into())],
-        Value::Relative(v) => vec![TrackSizing::Linear(v.into())],
-        Value::Linear(v) => vec![TrackSizing::Linear(v)],
-        Value::Fractional(v) => vec![TrackSizing::Fractional(v)],
-        Value::Int(v) => vec![TrackSizing::Auto; Value::Int(v).cast()?],
-        Value::Array(values) => values
-            .into_iter()
-            .filter_map(|v| v.cast().ok())
-            .collect(),
-    }
-
-    castable! {
-        TrackSizing,
-        Expected: "auto, linear, or fractional",
-        Value::Auto => Self::Auto,
-        Value::Length(v) => Self::Linear(v.into()),
-        Value::Relative(v) => Self::Linear(v.into()),
-        Value::Linear(v) => Self::Linear(v),
-        Value::Fractional(v) => Self::Fractional(v),
-    }
-
     let columns = args.named("columns")?.unwrap_or_default();
     let rows = args.named("rows")?.unwrap_or_default();
-    let tracks = Spec::new(columns, rows);
-
     let base_gutter: Vec<TrackSizing> = args.named("gutter")?.unwrap_or_default();
     let column_gutter = args.named("column-gutter")?;
     let row_gutter = args.named("row-gutter")?;
-    let gutter = Spec::new(
-        column_gutter.unwrap_or_else(|| base_gutter.clone()),
-        row_gutter.unwrap_or(base_gutter),
-    );
-
     Ok(Value::block(GridNode {
-        tracks,
-        gutter,
+        tracks: Spec::new(columns, rows),
+        gutter: Spec::new(
+            column_gutter.unwrap_or_else(|| base_gutter.clone()),
+            row_gutter.unwrap_or(base_gutter),
+        ),
         children: args.all().map(Node::into_block).collect(),
     }))
 }
@@ -57,17 +30,6 @@ pub struct GridNode {
     pub children: Vec<PackedNode>,
 }
 
-/// Defines how to size a grid cell along an axis.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub enum TrackSizing {
-    /// Fit the cell to its contents.
-    Auto,
-    /// A length stated in absolute values and/or relative to the parent's size.
-    Linear(Linear),
-    /// A length that is the fraction of the remaining free space in the parent.
-    Fractional(Fractional),
-}
-
 impl Layout for GridNode {
     fn layout(
         &self,
@@ -85,6 +47,42 @@ impl Layout for GridNode {
     }
 }
 
+/// Defines how to size a grid cell along an axis.
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+pub enum TrackSizing {
+    /// Fit the cell to its contents.
+    Auto,
+    /// A length stated in absolute values and/or relative to the parent's size.
+    Linear(Linear),
+    /// A length that is the fraction of the remaining free space in the parent.
+    Fractional(Fractional),
+}
+
+castable! {
+    Vec<TrackSizing>,
+    Expected: "integer or (auto, linear, fractional, or array thereof)",
+    Value::Auto => vec![TrackSizing::Auto],
+    Value::Length(v) => vec![TrackSizing::Linear(v.into())],
+    Value::Relative(v) => vec![TrackSizing::Linear(v.into())],
+    Value::Linear(v) => vec![TrackSizing::Linear(v)],
+    Value::Fractional(v) => vec![TrackSizing::Fractional(v)],
+    Value::Int(v) => vec![TrackSizing::Auto; Value::Int(v).cast()?],
+    Value::Array(values) => values
+        .into_iter()
+        .filter_map(|v| v.cast().ok())
+        .collect(),
+}
+
+castable! {
+    TrackSizing,
+    Expected: "auto, linear, or fractional",
+    Value::Auto => Self::Auto,
+    Value::Length(v) => Self::Linear(v.into()),
+    Value::Relative(v) => Self::Linear(v.into()),
+    Value::Linear(v) => Self::Linear(v),
+    Value::Fractional(v) => Self::Fractional(v),
+}
+
 /// Performs grid layout.
 struct GridLayouter<'a> {
     /// The children of the grid.
diff --git a/src/library/heading.rs b/src/library/heading.rs
index 96ff2688..a0b787f3 100644
--- a/src/library/heading.rs
+++ b/src/library/heading.rs
@@ -1,3 +1,5 @@
+//! Document-structuring section headings.
+
 use super::prelude::*;
 use super::{FontFamily, TextNode};
 
diff --git a/src/library/image.rs b/src/library/image.rs
index efb246a1..4e5acdc6 100644
--- a/src/library/image.rs
+++ b/src/library/image.rs
@@ -1,3 +1,5 @@
+//! Raster and vector graphics.
+
 use std::io;
 
 use super::prelude::*;
@@ -106,6 +108,12 @@ pub enum ImageFit {
     Stretch,
 }
 
+impl Default for ImageFit {
+    fn default() -> Self {
+        Self::Cover
+    }
+}
+
 castable! {
     ImageFit,
     Expected: "string",
@@ -116,9 +124,3 @@ castable! {
         _ => Err(r#"expected "cover", "contain" or "stretch""#)?,
     },
 }
-
-impl Default for ImageFit {
-    fn default() -> Self {
-        Self::Cover
-    }
-}
diff --git a/src/library/link.rs b/src/library/link.rs
index 40604a62..0f341793 100644
--- a/src/library/link.rs
+++ b/src/library/link.rs
@@ -1,3 +1,5 @@
+//! Hyperlinking.
+
 use super::prelude::*;
 use crate::util::EcoString;
 
diff --git a/src/library/list.rs b/src/library/list.rs
index 25eb3600..f407d8e9 100644
--- a/src/library/list.rs
+++ b/src/library/list.rs
@@ -1,3 +1,5 @@
+//! Unordered (bulleted) and ordered (numbered) lists.
+
 use std::hash::Hash;
 
 use super::prelude::*;
diff --git a/src/library/mod.rs b/src/library/mod.rs
index 1c97f529..61d3ccc0 100644
--- a/src/library/mod.rs
+++ b/src/library/mod.rs
@@ -3,44 +3,25 @@
 //! Call [`new`] to obtain a [`Scope`] containing all standard library
 //! definitions.
 
-mod align;
-mod columns;
-mod flow;
-mod grid;
-mod heading;
-mod image;
-mod link;
-mod list;
-mod pad;
-mod page;
-mod par;
-mod placed;
-mod shape;
-mod sized;
-mod spacing;
-mod stack;
-mod text;
-mod transform;
-mod utility;
-
-/// Helpful imports for creating library functionality.
-mod prelude {
-    pub use std::fmt::{self, Debug, Formatter};
-    pub use std::num::NonZeroUsize;
-    pub use std::rc::Rc;
-
-    pub use typst_macros::properties;
-
-    pub use crate::diag::{At, TypResult};
-    pub use crate::eval::{
-        Args, Construct, EvalContext, Node, Property, Set, Smart, Styles, Value,
-    };
-    pub use crate::frame::*;
-    pub use crate::geom::*;
-    pub use crate::layout::*;
-    pub use crate::syntax::{Span, Spanned};
-    pub use crate::util::{EcoString, OptionExt};
-}
+pub mod align;
+pub mod columns;
+pub mod flow;
+pub mod grid;
+pub mod heading;
+pub mod image;
+pub mod link;
+pub mod list;
+pub mod pad;
+pub mod page;
+pub mod par;
+pub mod placed;
+pub mod shape;
+pub mod sized;
+pub mod spacing;
+pub mod stack;
+pub mod text;
+pub mod transform;
+pub mod utility;
 
 pub use self::image::*;
 pub use align::*;
@@ -62,8 +43,37 @@ pub use text::*;
 pub use transform::*;
 pub use utility::*;
 
-use crate::eval::{Scope, Value};
-use crate::geom::*;
+macro_rules! prelude {
+    ($($reexport:item)*) => {
+        /// Helpful imports for creating library functionality.
+        pub mod prelude {
+            $(#[doc(no_inline)] $reexport)*
+        }
+    };
+}
+
+prelude! {
+    pub use std::fmt::{self, Debug, Formatter};
+    pub use std::num::NonZeroUsize;
+    pub use std::rc::Rc;
+
+    pub use typst_macros::properties;
+
+    pub use crate::diag::{At, TypResult};
+    pub use crate::eval::{
+        Args, Construct, EvalContext, Node, Property, Set, Smart, Styles, Value,
+    };
+    pub use crate::frame::*;
+    pub use crate::geom::*;
+    pub use crate::layout::{
+        Constrain, Constrained, Constraints, Layout, LayoutContext, PackedNode, Regions,
+    };
+    pub use crate::syntax::{Span, Spanned};
+    pub use crate::util::{EcoString, OptionExt};
+}
+
+use crate::eval::Scope;
+use prelude::*;
 
 /// Construct a scope containing all standard library definitions.
 pub fn new() -> Scope {
@@ -78,9 +88,8 @@ pub fn new() -> Scope {
     std.def_class::<ListNode<Ordered>>("enum");
 
     // Text functions.
-    // TODO(style): These should be classes, once that works for inline nodes.
-    std.def_func("strike", strike);
     std.def_func("underline", underline);
+    std.def_func("strike", strike);
     std.def_func("overline", overline);
     std.def_func("link", link);
 
@@ -93,8 +102,6 @@ pub fn new() -> Scope {
     std.def_func("v", v);
 
     // Layout functions.
-    // TODO(style): Decide which of these should be classes
-    // (and which of their properties should be settable).
     std.def_func("box", box_);
     std.def_func("block", block);
     std.def_func("stack", stack);
@@ -161,27 +168,27 @@ dynamic! {
 }
 
 castable! {
-    Paint,
-    Expected: "color",
-    Value::Color(color) => Paint::Solid(color),
-}
-
-castable! {
     usize,
     Expected: "non-negative integer",
     Value::Int(int) => int.try_into().map_err(|_| "must be at least zero")?,
 }
 
 castable! {
-    prelude::NonZeroUsize,
+    NonZeroUsize,
     Expected: "positive integer",
     Value::Int(int) => int
         .try_into()
-        .and_then(|n: usize| n.try_into())
+        .and_then(usize::try_into)
         .map_err(|_| "must be positive")?,
 }
 
 castable! {
+    Paint,
+    Expected: "color",
+    Value::Color(color) => Paint::Solid(color),
+}
+
+castable! {
     String,
     Expected: "string",
     Value::Str(string) => string.into(),
diff --git a/src/library/pad.rs b/src/library/pad.rs
index 75fea2e5..70d88b41 100644
--- a/src/library/pad.rs
+++ b/src/library/pad.rs
@@ -1,3 +1,5 @@
+//! Surrounding nodes with extra space.
+
 use super::prelude::*;
 
 /// `pad`: Pad content at the sides.
diff --git a/src/library/page.rs b/src/library/page.rs
index 100b4d0c..00f2dfc6 100644
--- a/src/library/page.rs
+++ b/src/library/page.rs
@@ -1,4 +1,4 @@
-#![allow(unused)]
+//! Pages of paper.
 
 use std::fmt::{self, Display, Formatter};
 use std::str::FromStr;
@@ -6,11 +6,6 @@ use std::str::FromStr;
 use super::prelude::*;
 use super::{ColumnsNode, PadNode};
 
-/// `pagebreak`: Start a new page.
-pub fn pagebreak(_: &mut EvalContext, _: &mut Args) -> TypResult<Value> {
-    Ok(Value::Node(Node::Pagebreak))
-}
-
 /// Layouts its child onto one or multiple pages.
 #[derive(Clone, PartialEq, Hash)]
 pub struct PageNode {
@@ -42,7 +37,7 @@ impl PageNode {
     pub const FILL: Option<Paint> = None;
     /// How many columns the page has.
     pub const COLUMNS: NonZeroUsize = NonZeroUsize::new(1).unwrap();
-    /// How many columns the page has.
+    /// How much space is between the page's columns.
     pub const COLUMN_GUTTER: Linear = Relative::new(0.04).into();
 }
 
@@ -74,11 +69,12 @@ impl Set for PageNode {
         }
 
         let margins = args.named("margins")?;
-        styles.set_opt(Self::FLIPPED, args.named("flipped")?);
         styles.set_opt(Self::LEFT, args.named("left")?.or(margins));
         styles.set_opt(Self::TOP, args.named("top")?.or(margins));
         styles.set_opt(Self::RIGHT, args.named("right")?.or(margins));
         styles.set_opt(Self::BOTTOM, args.named("bottom")?.or(margins));
+
+        styles.set_opt(Self::FLIPPED, args.named("flipped")?);
         styles.set_opt(Self::FILL, args.named("fill")?);
         styles.set_opt(Self::COLUMNS, args.named("columns")?);
         styles.set_opt(Self::COLUMN_GUTTER, args.named("column-gutter")?);
@@ -163,6 +159,36 @@ impl Debug for PageNode {
     }
 }
 
+/// `pagebreak`: Start a new page.
+pub fn pagebreak(_: &mut EvalContext, _: &mut Args) -> TypResult<Value> {
+    Ok(Value::Node(Node::Pagebreak))
+}
+
+/// Defines default margins for a class of related papers.
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+pub enum PaperClass {
+    Custom,
+    Base,
+    US,
+    Newspaper,
+    Book,
+}
+
+impl PaperClass {
+    /// The default margins for this page class.
+    fn default_margins(self) -> Sides<Linear> {
+        let f = |r| Relative::new(r).into();
+        let s = |l, t, r, b| Sides::new(f(l), f(t), f(r), f(b));
+        match self {
+            Self::Custom => s(0.1190, 0.0842, 0.1190, 0.0842),
+            Self::Base => s(0.1190, 0.0842, 0.1190, 0.0842),
+            Self::US => s(0.1760, 0.1092, 0.1760, 0.0910),
+            Self::Newspaper => s(0.0455, 0.0587, 0.0455, 0.0294),
+            Self::Book => s(0.1200, 0.0852, 0.1500, 0.0965),
+        }
+    }
+}
+
 /// Specification of a paper.
 #[derive(Debug, Copy, Clone)]
 pub struct Paper {
@@ -197,37 +223,6 @@ impl Default for Paper {
     }
 }
 
-castable! {
-    Paper,
-    Expected: "string",
-    Value::Str(string) => Paper::from_str(&string).map_err(|e| e.to_string())?,
-}
-
-/// Defines default margins for a class of related papers.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub enum PaperClass {
-    Custom,
-    Base,
-    US,
-    Newspaper,
-    Book,
-}
-
-impl PaperClass {
-    /// The default margins for this page class.
-    fn default_margins(self) -> Sides<Linear> {
-        let f = |r| Relative::new(r).into();
-        let s = |l, t, r, b| Sides::new(f(l), f(t), f(r), f(b));
-        match self {
-            Self::Custom => s(0.1190, 0.0842, 0.1190, 0.0842),
-            Self::Base => s(0.1190, 0.0842, 0.1190, 0.0842),
-            Self::US => s(0.1760, 0.1092, 0.1760, 0.0910),
-            Self::Newspaper => s(0.0455, 0.0587, 0.0455, 0.0294),
-            Self::Book => s(0.1200, 0.0852, 0.1500, 0.0965),
-        }
-    }
-}
-
 /// Defines paper constants and a paper parsing implementation.
 macro_rules! papers {
     ($(($var:ident: $class:ident, $width:expr, $height: expr, $($pats:tt)*))*) => {
@@ -252,18 +247,6 @@ macro_rules! papers {
                 }
             }
         }
-
-        /// The error when parsing a [`Paper`] from a string fails.
-        #[derive(Debug, Copy, Clone, Eq, PartialEq)]
-        pub struct ParsePaperError;
-
-        impl Display for ParsePaperError {
-            fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-                f.pad("invalid paper name")
-            }
-        }
-
-        impl std::error::Error for ParsePaperError {}
     };
 }
 
@@ -421,3 +404,21 @@ papers! {
     (PRESENTATION_16_9:    Base,      297.0, 167.0625, "presentation-16-9")
     (PRESENTATION_4_3:     Base,      280.0, 210.0,    "presentation-4-3")
 }
+
+castable! {
+    Paper,
+    Expected: "string",
+    Value::Str(string) => Paper::from_str(&string).map_err(|e| e.to_string())?,
+}
+
+/// The error when parsing a [`Paper`] from a string fails.
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub struct ParsePaperError;
+
+impl Display for ParsePaperError {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        f.pad("invalid paper name")
+    }
+}
+
+impl std::error::Error for ParsePaperError {}
diff --git a/src/library/par.rs b/src/library/par.rs
index 26280d8e..2c12f9f6 100644
--- a/src/library/par.rs
+++ b/src/library/par.rs
@@ -1,3 +1,5 @@
+//! Paragraph layout.
+
 use std::fmt::{self, Debug, Formatter};
 use std::rc::Rc;
 
@@ -9,16 +11,6 @@ use super::prelude::*;
 use super::{shape, ShapedText, SpacingKind, SpacingNode, TextNode};
 use crate::util::{EcoString, RangeExt, RcExt, SliceExt};
 
-/// `parbreak`: Start a new paragraph.
-pub fn parbreak(_: &mut EvalContext, _: &mut Args) -> TypResult<Value> {
-    Ok(Value::Node(Node::Parbreak))
-}
-
-/// `linebreak`: Start a new line.
-pub fn linebreak(_: &mut EvalContext, _: &mut Args) -> TypResult<Value> {
-    Ok(Value::Node(Node::Linebreak))
-}
-
 /// A node that arranges its children into a paragraph.
 #[derive(Hash)]
 pub struct ParNode(pub Vec<ParChild>);
@@ -62,17 +54,17 @@ impl Set for ParNode {
             dir = Some(v);
         }
 
-        let mut align = None;
-        if let Some(Spanned { v, span }) = args.named::<Spanned<Align>>("align")? {
-            if v.axis() != SpecAxis::Horizontal {
-                bail!(span, "must be horizontal");
-            }
-            align = Some(v);
-        }
-
-        if let (Some(dir), None) = (dir, align) {
-            align = Some(if dir == Dir::LTR { Align::Left } else { Align::Right });
-        }
+        let align =
+            if let Some(Spanned { v, span }) = args.named::<Spanned<Align>>("align")? {
+                if v.axis() != SpecAxis::Horizontal {
+                    bail!(span, "must be horizontal");
+                }
+                Some(v)
+            } else if let Some(dir) = dir {
+                Some(if dir == Dir::LTR { Align::Left } else { Align::Right })
+            } else {
+                None
+            };
 
         styles.set_opt(Self::DIR, dir);
         styles.set_opt(Self::ALIGN, align);
@@ -107,8 +99,7 @@ impl Layout for ParNode {
 impl ParNode {
     /// Concatenate all text in the paragraph into one string, replacing spacing
     /// with a space character and other non-text nodes with the object
-    /// replacement character. Returns the full text alongside the range each
-    /// child spans in the text.
+    /// replacement character.
     fn collect_text(&self) -> String {
         let mut text = String::new();
         for string in self.strings() {
@@ -190,6 +181,16 @@ impl Debug for ParChild {
     }
 }
 
+/// `parbreak`: Start a new paragraph.
+pub fn parbreak(_: &mut EvalContext, _: &mut Args) -> TypResult<Value> {
+    Ok(Value::Node(Node::Parbreak))
+}
+
+/// `linebreak`: Start a new line.
+pub fn linebreak(_: &mut EvalContext, _: &mut Args) -> TypResult<Value> {
+    Ok(Value::Node(Node::Linebreak))
+}
+
 /// A paragraph representation in which children are already layouted and text
 /// is separated into shapable runs.
 struct ParLayouter<'a> {
diff --git a/src/library/placed.rs b/src/library/placed.rs
index 589a299b..bdf3e2cd 100644
--- a/src/library/placed.rs
+++ b/src/library/placed.rs
@@ -1,3 +1,5 @@
+//! Absolute placement of nodes.
+
 use super::prelude::*;
 use super::AlignNode;
 
diff --git a/src/library/shape.rs b/src/library/shape.rs
index a9c9b333..3eb1a794 100644
--- a/src/library/shape.rs
+++ b/src/library/shape.rs
@@ -1,3 +1,5 @@
+//! Colorable geometrical shapes.
+
 use std::f64::consts::SQRT_2;
 
 use super::prelude::*;
diff --git a/src/library/sized.rs b/src/library/sized.rs
index 6d677ca8..49b515cf 100644
--- a/src/library/sized.rs
+++ b/src/library/sized.rs
@@ -1,3 +1,5 @@
+//! Horizontal and vertical sizing of nodes.
+
 use super::prelude::*;
 
 /// `box`: Size content and place it into a paragraph.
diff --git a/src/library/spacing.rs b/src/library/spacing.rs
index b5ecce69..e552828c 100644
--- a/src/library/spacing.rs
+++ b/src/library/spacing.rs
@@ -1,3 +1,5 @@
+//! Horizontal and vertical spacing between nodes.
+
 use super::prelude::*;
 
 /// `h`: Horizontal spacing.
diff --git a/src/library/stack.rs b/src/library/stack.rs
index 8a1f0fd5..dfe5e245 100644
--- a/src/library/stack.rs
+++ b/src/library/stack.rs
@@ -1,3 +1,5 @@
+//! Side-by-side layout of nodes along an axis.
+
 use std::fmt::{self, Debug, Formatter};
 
 use super::prelude::*;
@@ -215,17 +217,17 @@ impl<'a> StackLayouter<'a> {
         }
 
         let mut output = Frame::new(size);
-        let mut before = Length::zero();
+        let mut cursor = Length::zero();
         let mut ruler: Align = self.stack.dir.start().into();
 
         // Place all frames.
         for item in self.items.drain(..) {
             match item {
                 StackItem::Absolute(v) => {
-                    before += v;
+                    cursor += v;
                 }
                 StackItem::Fractional(v) => {
-                    before += v.resolve(self.fr, remaining);
+                    cursor += v.resolve(self.fr, remaining);
                 }
                 StackItem::Frame(frame, align) => {
                     if self.stack.dir.is_positive() {
@@ -239,13 +241,13 @@ impl<'a> StackLayouter<'a> {
                     let child = frame.size.get(self.axis);
                     let block = ruler.resolve(parent - self.used.main)
                         + if self.stack.dir.is_positive() {
-                            before
+                            cursor
                         } else {
-                            self.used.main - child - before
+                            self.used.main - child - cursor
                         };
 
                     let pos = Gen::new(Length::zero(), block).to_point(self.axis);
-                    before += child;
+                    cursor += child;
                     output.push_frame(pos, frame);
                 }
             }
diff --git a/src/library/text.rs b/src/library/text.rs
index 99c68f79..df71fec9 100644
--- a/src/library/text.rs
+++ b/src/library/text.rs
@@ -1,3 +1,5 @@
+//! Text shaping and styling.
+
 use std::borrow::Cow;
 use std::convert::TryInto;
 use std::fmt::{self, Debug, Formatter};
@@ -15,33 +17,6 @@ use crate::font::{
 use crate::geom::{Dir, Em, Length, Point, Size};
 use crate::util::{EcoString, SliceExt};
 
-/// `strike`: Typeset striken-through text.
-pub fn strike(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    line_impl(args, LineKind::Strikethrough)
-}
-
-/// `underline`: Typeset underlined text.
-pub fn underline(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    line_impl(args, LineKind::Underline)
-}
-
-/// `overline`: Typeset text with an overline.
-pub fn overline(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    line_impl(args, LineKind::Overline)
-}
-
-fn line_impl(args: &mut Args, kind: LineKind) -> TypResult<Value> {
-    let stroke = args.named("stroke")?.or_else(|| args.find());
-    let thickness = args.named::<Linear>("thickness")?.or_else(|| args.find());
-    let offset = args.named("offset")?;
-    let extent = args.named("extent")?.unwrap_or_default();
-    let body: Node = args.expect("body")?;
-    let deco = LineDecoration { kind, stroke, thickness, offset, extent };
-    Ok(Value::Node(
-        body.styled(Styles::one(TextNode::LINES, vec![deco])),
-    ))
-}
-
 /// A single run of text with the same style.
 #[derive(Hash)]
 pub struct TextNode {
@@ -216,6 +191,21 @@ impl Debug for FontFamily {
     }
 }
 
+dynamic! {
+    FontFamily: "font family",
+    Value::Str(string) => Self::named(&string),
+}
+
+castable! {
+    Vec<FontFamily>,
+    Expected: "string, generic family or array thereof",
+    Value::Str(string) => vec![FontFamily::named(&string)],
+    Value::Array(values) => {
+        values.into_iter().filter_map(|v| v.cast().ok()).collect()
+    },
+    @family: FontFamily => vec![family.clone()],
+}
+
 /// A specific font family like "Arial".
 #[derive(Clone, Eq, PartialEq, Hash)]
 pub struct NamedFamily(String);
@@ -238,21 +228,6 @@ impl Debug for NamedFamily {
     }
 }
 
-dynamic! {
-    FontFamily: "font family",
-    Value::Str(string) => Self::named(&string),
-}
-
-castable! {
-    Vec<FontFamily>,
-    Expected: "string, generic family or array thereof",
-    Value::Str(string) => vec![FontFamily::named(&string)],
-    Value::Array(values) => {
-        values.into_iter().filter_map(|v| v.cast().ok()).collect()
-    },
-    @family: FontFamily => vec![family.clone()],
-}
-
 castable! {
     Vec<NamedFamily>,
     Expected: "string or array of strings",
@@ -421,6 +396,33 @@ castable! {
         .collect(),
 }
 
+/// `strike`: Typeset striken-through text.
+pub fn strike(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+    line_impl(args, LineKind::Strikethrough)
+}
+
+/// `underline`: Typeset underlined text.
+pub fn underline(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+    line_impl(args, LineKind::Underline)
+}
+
+/// `overline`: Typeset text with an overline.
+pub fn overline(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+    line_impl(args, LineKind::Overline)
+}
+
+fn line_impl(args: &mut Args, kind: LineKind) -> TypResult<Value> {
+    let stroke = args.named("stroke")?.or_else(|| args.find());
+    let thickness = args.named::<Linear>("thickness")?.or_else(|| args.find());
+    let offset = args.named("offset")?;
+    let extent = args.named("extent")?.unwrap_or_default();
+    let body: Node = args.expect("body")?;
+    let deco = LineDecoration { kind, stroke, thickness, offset, extent };
+    Ok(Value::Node(
+        body.styled(Styles::one(TextNode::LINES, vec![deco])),
+    ))
+}
+
 /// Defines a line that is positioned over, under or on top of text.
 #[derive(Debug, Clone, Eq, PartialEq, Hash)]
 pub struct LineDecoration {
diff --git a/src/library/transform.rs b/src/library/transform.rs
index 6a6b4034..ef468d7b 100644
--- a/src/library/transform.rs
+++ b/src/library/transform.rs
@@ -1,3 +1,5 @@
+//! Affine transformations on nodes.
+
 use super::prelude::*;
 use crate::geom::Transform;
 
@@ -20,7 +22,7 @@ pub fn scale(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 
 /// `rotate`: Rotate content without affecting layout.
 pub fn rotate(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
-    let angle = args.expect("angle")?;
+    let angle = args.named("angle")?.or_else(|| args.find()).unwrap_or_default();
     let transform = Transform::rotation(angle);
     transform_impl(args, transform)
 }
diff --git a/src/library/utility.rs b/src/library/utility.rs
index b2435e8a..4e4632c4 100644
--- a/src/library/utility.rs
+++ b/src/library/utility.rs
@@ -1,3 +1,5 @@
+//! Computational utility functions.
+
 use std::cmp::Ordering;
 use std::str::FromStr;
 
@@ -44,7 +46,7 @@ pub fn join(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     Ok(result)
 }
 
-/// `int`: Try to convert a value to a integer.
+/// `int`: Convert a value to a integer.
 pub fn int(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect("value")?;
     Ok(Value::Int(match v {
@@ -59,7 +61,7 @@ pub fn int(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     }))
 }
 
-/// `float`: Try to convert a value to a float.
+/// `float`: Convert a value to a float.
 pub fn float(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect("value")?;
     Ok(Value::Float(match v {