Non-fatal argument parsing 🌋

12 files changed, 449 insertions, 896 deletions

diff --git a/src/library/align.rs b/src/library/align.rs
deleted file mode 100644
index ca2c787b..00000000
--- a/src/library/align.rs
+++ /dev/null
@@ -1,35 +0,0 @@
-use crate::func::prelude::*;
-use super::maps::{PosAxisMap, AlignmentKey};
-
-
-function! {
-    /// `align`: Aligns content along the layouting axes.
-    #[derive(Debug, PartialEq)]
-    pub struct AlignFunc {
-        body: Option<SyntaxTree>,
-        map: PosAxisMap<AlignmentKey>,
-    }
-
-    parse(header, body, ctx) {
-        AlignFunc {
-            body: parse!(optional: body, ctx),
-            map: PosAxisMap::new(&mut header.args)?,
-        }
-    }
-
-    layout(self, mut ctx) {
-        ctx.base = ctx.spaces[0].dimensions;
-
-        let map = self.map.dedup(ctx.axes, |alignment| alignment.axis(ctx.axes))?;
-        for &axis in &[Primary, Secondary] {
-            if let Some(alignment) = map.get(axis) {
-                *ctx.alignment.get_mut(axis) = alignment.to_generic(ctx.axes, axis)?;
-            }
-        }
-
-        match &self.body {
-            Some(body) => vec![AddMultiple(layout(&body, ctx).await?)],
-            None => vec![SetAlignment(ctx.alignment)],
-        }
-    }
-}
diff --git a/src/library/boxed.rs b/src/library/boxed.rs
deleted file mode 100644
index af236da4..00000000
--- a/src/library/boxed.rs
+++ /dev/null
@@ -1,57 +0,0 @@
-use smallvec::smallvec;
-
-use crate::func::prelude::*;
-use super::maps::ExtentMap;
-
-
-function! {
-    /// `box`: Layouts content into a box.
-    #[derive(Debug, PartialEq)]
-    pub struct BoxFunc {
-        body: SyntaxTree,
-        map: ExtentMap<PSize>,
-        debug: Option<bool>,
-    }
-
-    parse(header, body, ctx) {
-        BoxFunc {
-            body: parse!(optional: body, ctx).unwrap_or(SyntaxTree::new()),
-            map: ExtentMap::new(&mut header.args, false)?,
-            debug: header.args.get_key_opt::<bool>("debug")?,
-        }
-    }
-
-    layout(self, mut ctx) {
-        ctx.repeat = false;
-
-        if let Some(debug) = self.debug {
-            ctx.debug = debug;
-        }
-
-        let map = self.map.dedup(ctx.axes)?;
-
-        // Try to layout this box in all spaces until it fits into some space.
-        let mut error = None;
-        for &(mut space) in &ctx.spaces {
-            let mut ctx = ctx.clone();
-
-            for &axis in &[Horizontal, Vertical] {
-                if let Some(psize) = map.get(axis) {
-                    let size = psize.scaled(ctx.base.get(axis));
-                    *ctx.base.get_mut(axis) = size;
-                    *space.dimensions.get_mut(axis) = size;
-                    *space.expansion.get_mut(axis) = true;
-                }
-            }
-
-            ctx.spaces = smallvec![space];
-
-            match layout(&self.body, ctx).await {
-                Ok(layouts) => return Ok(vec![AddMultiple(layouts)]),
-                Err(err) => error = Some(err),
-            }
-        }
-
-        return Err(error.expect("expected at least one space"));
-    }
-}
diff --git a/src/library/direction.rs b/src/library/direction.rs
deleted file mode 100644
index b7a6e212..00000000
--- a/src/library/direction.rs
+++ /dev/null
@@ -1,43 +0,0 @@
-use crate::func::prelude::*;
-use super::maps::PosAxisMap;
-
-
-function! {
-    /// `direction`: Sets the directions of the layouting axes.
-    #[derive(Debug, PartialEq)]
-    pub struct DirectionFunc {
-        body: Option<SyntaxTree>,
-        map: PosAxisMap<Direction>,
-    }
-
-    parse(header, body, ctx) {
-        DirectionFunc {
-            body: parse!(optional: body, ctx),
-            map: PosAxisMap::new(&mut header.args)?,
-        }
-    }
-
-    layout(self, mut ctx) {
-        ctx.base = ctx.spaces[0].dimensions;
-
-        let map = self.map.dedup(ctx.axes, |direction| {
-            Some(direction.axis().to_generic(ctx.axes))
-        })?;
-
-        map.with(Primary, |&dir| ctx.axes.primary = dir);
-        map.with(Secondary, |&dir| ctx.axes.secondary = dir);
-
-        if ctx.axes.primary.axis() == ctx.axes.secondary.axis() {
-            error!(
-                "invalid aligned primary and secondary axes: `{}`, `{}`",
-                format!("{:?}", ctx.axes.primary).to_lowercase(),
-                format!("{:?}", ctx.axes.secondary).to_lowercase(),
-            );
-        }
-
-        match &self.body {
-            Some(body) => vec![AddMultiple(layout(&body, ctx).await?)],
-            None => vec![Command::SetAxes(ctx.axes)],
-        }
-    }
-}
diff --git a/src/library/font.rs b/src/library/font.rs
new file mode 100644
index 00000000..b4a6218a
--- /dev/null
+++ b/src/library/font.rs
@@ -0,0 +1,104 @@
+use toddle::query::{FontWeight, FontStyle};
+use super::*;
+
+
+function! {
+    /// `font.family`: Set the font family.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct FontFamilyFunc {
+        body: Option<SyntaxModel>,
+        list: Vec<String>,
+    }
+
+    parse(header, body, ctx, errors, decos) {
+        FontFamilyFunc {
+            body: body!(opt: body, ctx, errors, decos),
+            list: header.args.pos.get_all::<StringLike>(errors).collect(),
+        }
+    }
+
+    layout(self, ctx, errors) {
+        styled(&self.body, ctx, Some(&self.list),
+            |s, l| s.fallback.list = l.clone())
+    }
+}
+
+function! {
+    /// `font.style`: Set the font style (normal / italic).
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct FontStyleFunc {
+        body: Option<SyntaxModel>,
+        style: Option<FontStyle>,
+    }
+
+    parse(header, body, ctx, errors, decos) {
+        FontStyleFunc {
+            body: body!(opt: body, ctx, errors, decos),
+            style: header.args.pos.get::<FontStyle>(errors)
+                .or_missing(errors, header.name.span, "style"),
+        }
+    }
+
+    layout(self, ctx, errors) {
+        styled(&self.body, ctx, self.style, |t, s| t.variant.style = s)
+    }
+}
+
+function! {
+    /// `font.weight`: Set text with a given weight.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct FontWeightFunc {
+        body: Option<SyntaxModel>,
+        weight: Option<FontWeight>,
+    }
+
+    parse(header, body, ctx, errors, decos) {
+        let body = body!(opt: body, ctx, errors, decos);
+        let weight = header.args.pos.get::<Spanned<FontWeight>>(errors)
+            .map(|Spanned { v: (weight, is_clamped), span }| {
+                if is_clamped {
+                    errors.push(err!(@Warning: span;
+                        "weight should be between \
+                         100 and 900, clamped to {}", weight.0));
+                }
+
+                weight
+            })
+            .or_missing(errors, header.name.span, "weight");
+
+        FontWeightFunc { body, weight }
+    }
+
+    layout(self, ctx, errors) {
+        styled(&self.body, ctx, self.weight, |t, w| t.variant.weight = w)
+    }
+}
+
+function! {
+    /// `font.size`: Sets the font size.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct FontSizeFunc {
+        body: Option<SyntaxModel>,
+        size: Option<ScaleSize>,
+    }
+
+    parse(header, body, ctx, errors, decos) {
+        FontSizeFunc {
+            body: body!(opt: body, ctx, errors, decos),
+            size: header.args.pos.get::<FSize>(errors)
+                .or_missing(errors, header.name.span, "size")
+        }
+    }
+
+    layout(self, ctx, errors) {
+        styled(&self.body, ctx, self.size, |t, s| {
+            match s {
+                ScaleSize::Absolute(size) => {
+                    t.base_font_size = size;
+                    t.font_scale = 1.0;
+                }
+                ScaleSize::Scaled(scale) => t.font_scale = scale,
+            }
+        })
+    }
+}
diff --git a/src/library/layout.rs b/src/library/layout.rs
new file mode 100644
index 00000000..fb8633b1
--- /dev/null
+++ b/src/library/layout.rs
@@ -0,0 +1,135 @@
+use smallvec::smallvec;
+use super::*;
+
+
+function! {
+    /// `align`: Aligns content along the layouting axes.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct AlignFunc {
+        body: Option<SyntaxModel>,
+        map: PosAxisMap<AlignmentValue>,
+    }
+
+    parse(header, body, ctx, errors, decos) {
+        AlignFunc {
+            body: body!(opt: body, ctx, errors, decos),
+            map: PosAxisMap::parse::<AxisKey, AlignmentValue>(errors, &mut header.args),
+        }
+    }
+
+    layout(self, ctx, errors) {
+        ctx.base = ctx.spaces[0].dimensions;
+
+        let map = self.map.dedup(errors, ctx.axes, |alignment| alignment.axis(ctx.axes));
+        for &axis in &[Primary, Secondary] {
+            if let Some(Spanned { v: alignment, span }) = map.get_spanned(axis) {
+                if let Some(generic) = alignment.to_generic(ctx.axes, axis) {
+                    *ctx.alignment.get_mut(axis) = generic;
+                } else {
+                    errors.push(err!(span;
+                        "invalid alignment `{}` for {} axis", alignment, axis));
+                }
+            }
+        }
+
+        match &self.body {
+            Some(body) => {
+                let layouted = layout(body, ctx).await;
+                errors.extend(layouted.errors);
+                vec![AddMultiple(layouted.output)]
+            }
+            None => vec![SetAlignment(ctx.alignment)],
+        }
+    }
+}
+
+function! {
+    /// `direction`: Sets the directions of the layouting axes.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct DirectionFunc {
+        name_span: Span,
+        body: Option<SyntaxModel>,
+        map: PosAxisMap<Direction>,
+    }
+
+    parse(header, body, ctx, errors, decos) {
+        DirectionFunc {
+            name_span: header.name.span,
+            body: body!(opt: body, ctx, errors, decos),
+            map: PosAxisMap::parse::<AxisKey, Direction>(errors, &mut header.args),
+        }
+    }
+
+    layout(self, ctx, errors) {
+        ctx.base = ctx.spaces[0].dimensions;
+
+        let map = self.map.dedup(errors, ctx.axes, |direction| {
+            Some(direction.axis().to_generic(ctx.axes))
+        });
+
+        let mut axes = ctx.axes;
+
+        map.with(Primary, |&dir| axes.primary = dir);
+        map.with(Secondary, |&dir| axes.secondary = dir);
+
+        if axes.primary.axis() == axes.secondary.axis() {
+            errors.push(err!(self.name_span;
+                "invalid aligned primary and secondary axes: `{}`, `{}`",
+                ctx.axes.primary, ctx.axes.secondary));
+        } else {
+            ctx.axes = axes;
+        }
+
+        match &self.body {
+            Some(body) => {
+                let layouted = layout(body, ctx).await;
+                errors.extend(layouted.errors);
+                vec![AddMultiple(layouted.output)]
+            }
+            None => vec![SetAxes(ctx.axes)],
+        }
+    }
+}
+
+function! {
+    /// `box`: Layouts content into a box.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct BoxFunc {
+        body: SyntaxModel,
+        extents: AxisMap<PSize>,
+        debug: Option<bool>,
+    }
+
+    parse(header, body, ctx, errors, decos) {
+        BoxFunc {
+            body: body!(opt: body, ctx, errors, decos).unwrap_or(SyntaxModel::new()),
+            extents: AxisMap::parse::<ExtentKey, PSize>(errors, &mut header.args.key),
+            debug: header.args.key.get::<bool>(errors, "debug"),
+        }
+    }
+
+    layout(self, ctx, errors) {
+        ctx.repeat = false;
+        ctx.spaces.truncate(1);
+
+        if let Some(debug) = self.debug {
+            ctx.debug = debug;
+        }
+
+        let map = self.extents.dedup(errors, ctx.axes);
+        for &axis in &[Horizontal, Vertical] {
+            if let Some(psize) = map.get(axis) {
+                let size = psize.scaled(ctx.base.get(axis));
+                *ctx.base.get_mut(axis) = size;
+                *ctx.spaces[0].dimensions.get_mut(axis) = size;
+                *ctx.spaces[0].expansion.get_mut(axis) = true;
+            }
+        }
+
+        let layouted = layout(&self.body, ctx).await;
+        let layout = layouted.output.into_iter().next().unwrap();
+        errors.extend(layouted.errors);
+
+        vec![Add(layout)]
+    }
+}
diff --git a/src/library/maps/alignment.rs b/src/library/maps/alignment.rs
deleted file mode 100644
index 8654e280..00000000
--- a/src/library/maps/alignment.rs
+++ /dev/null
@@ -1,77 +0,0 @@
-use super::*;
-use AlignmentKey::*;
-
-
-/// An argument key which describes a target alignment.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub enum AlignmentKey {
-    Align(Alignment),
-    Left,
-    Top,
-    Right,
-    Bottom,
-}
-
-impl AlignmentKey {
-    /// The generic axis this alignment key corresponds to in the given system
-    /// of layouting axes. `None` if the alignment is generic.
-    pub fn axis(self, axes: LayoutAxes) -> Option<GenericAxis> {
-        match self {
-            Left | Right => Some(Horizontal.to_generic(axes)),
-            Top | Bottom => Some(Vertical.to_generic(axes)),
-            Align(_) => None,
-        }
-    }
-
-    /// The generic version of this alignment in the given system of layouting
-    /// axes.
-    ///
-    /// Returns an error if the alignment is invalid for the given axis.
-    pub fn to_generic(self, axes: LayoutAxes, axis: GenericAxis) -> LayoutResult<Alignment> {
-        let specific = axis.to_specific(axes);
-        let start = match axes.get(axis).is_positive() {
-            true => Origin,
-            false => End,
-        };
-
-        Ok(match (self, specific) {
-            (Align(alignment), _) => alignment,
-            (Left, Horizontal) | (Top, Vertical) => start,
-            (Right, Horizontal) | (Bottom, Vertical) => start.inv(),
-
-            _ => error!(
-                "invalid alignment `{}` for {} axis",
-                format!("{:?}", self).to_lowercase(),
-                format!("{:?}", axis).to_lowercase()
-            )
-        })
-    }
-
-    /// The specific version of this alignment in the given system of layouting
-    /// axes.
-    pub fn to_specific(self, axes: LayoutAxes, axis: SpecificAxis) -> AlignmentKey {
-        let direction = axes.get_specific(axis);
-        if let Align(alignment) = self {
-            match (direction, alignment) {
-                (LeftToRight, Origin) | (RightToLeft, End) => Left,
-                (LeftToRight, End) | (RightToLeft, Origin) => Right,
-                (TopToBottom, Origin) | (BottomToTop, End) => Top,
-                (TopToBottom, End) | (BottomToTop, Origin) => Bottom,
-                (_, Center) => self,
-            }
-        } else {
-            self
-        }
-    }
-}
-
-key!(AlignmentKey, "alignment",
-    "origin" => Align(Origin),
-    "center" => Align(Center),
-    "end"    => Align(End),
-
-    "left"   => Left,
-    "top"    => Top,
-    "right"  => Right,
-    "bottom" => Bottom,
-);
diff --git a/src/library/maps/axis.rs b/src/library/maps/axis.rs
deleted file mode 100644
index 3c3a8c11..00000000
--- a/src/library/maps/axis.rs
+++ /dev/null
@@ -1,130 +0,0 @@
-use super::*;
-use AxisKey::*;
-
-
-/// An argument key which identifies a layouting axis.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub enum AxisKey {
-    Generic(GenericAxis),
-    Specific(SpecificAxis),
-}
-
-impl AxisKey {
-    /// The generic version of this axis key in the given system of axes.
-    pub fn to_generic(self, axes: LayoutAxes) -> GenericAxis {
-        match self {
-            Generic(axis) => axis,
-            Specific(axis) => axis.to_generic(axes),
-        }
-    }
-
-    /// The specific version of this axis key in the given system of axes.
-    pub fn to_specific(self, axes: LayoutAxes) -> SpecificAxis {
-        match self {
-            Generic(axis) => axis.to_specific(axes),
-            Specific(axis) => axis,
-        }
-    }
-}
-
-key!(AxisKey, "axis",
-    "horizontal" | "h" => Specific(Horizontal),
-    "vertical"   | "v" => Specific(Vertical),
-    "primary"    | "p" => Generic(Primary),
-    "secondary"  | "s" => Generic(Secondary),
-);
-
-key!(Direction, "direction",
-    "left-to-right" | "ltr" => LeftToRight,
-    "right-to-left" | "rtl" => RightToLeft,
-    "top-to-bottom" | "ttb" => TopToBottom,
-    "bottom-to-top" | "btt" => BottomToTop,
-);
-
-/// A map for storing extents along axes.
-#[derive(Debug, Clone, PartialEq)]
-pub struct ExtentMap<E: ExpressionKind + Copy>(ConsistentMap<AxisKey, E>);
-
-impl<E: ExpressionKind + Copy> ExtentMap<E> {
-    /// Parse an extent map from the function args.
-    ///
-    /// If `all` is true other arguments will create an error, otherwise
-    /// they are left intact.
-    pub fn new(args: &mut FuncArgs, all: bool) -> ParseResult<ExtentMap<E>> {
-        let mut map = ConsistentMap::new();
-
-        for arg in args.iter_keys() {
-            let key = match arg.key.v.as_str() {
-                "width"          | "w"  => AxisKey::Specific(Horizontal),
-                "height"         | "h"  => AxisKey::Specific(Vertical),
-                "primary-size"   | "ps" => AxisKey::Generic(Primary),
-                "secondary-size" | "ss" => AxisKey::Generic(Secondary),
-
-                _ => if all {
-                    error!("expected dimension")
-                } else {
-                    args.add_key_pair(arg);
-                    continue;
-                }
-            };
-
-            let e = E::from_expr(arg.value)?;
-            map.add(key, e)?;
-        }
-
-        Ok(ExtentMap(map))
-    }
-
-    /// Deduplicate from generic to specific axes.
-    pub fn dedup(&self, axes: LayoutAxes) -> LayoutResult<ConsistentMap<SpecificAxis, E>> {
-        self.0.dedup(|key, &val| Ok((key.to_specific(axes), val)))
-    }
-}
-
-/// An argument key which identifies an axis, but allows for positional
-/// arguments with unspecified axes.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub enum PosAxisKey {
-    /// The first positional argument.
-    First,
-    /// The second positional argument.
-    Second,
-    /// An axis keyword argument.
-    Keyword(AxisKey),
-}
-
-/// A map for storing some data for via keyword or positionally given axes.
-#[derive(Debug, Clone, PartialEq)]
-pub struct PosAxisMap<E: ExpressionKind + Copy>(ConsistentMap<PosAxisKey, E>);
-
-impl<E: ExpressionKind + Copy> PosAxisMap<E> {
-    /// Parse a positional axis map from the function args.
-    pub fn new(args: &mut FuncArgs) -> ParseResult<PosAxisMap<E>> {
-        let mut map = ConsistentMap::new();
-
-        map.add_opt(PosAxisKey::First, args.get_pos_opt::<E>()?)?;
-        map.add_opt(PosAxisKey::Second, args.get_pos_opt::<E>()?)?;
-
-        for arg in args.iter_keys() {
-            let axis = AxisKey::from_ident(&arg.key)?;
-            let value = E::from_expr(arg.value)?;
-
-            map.add(PosAxisKey::Keyword(axis), value)?;
-        }
-
-        Ok(PosAxisMap(map))
-    }
-
-    /// Deduplicate from positional or specific to generic axes.
-    pub fn dedup<F>(&self, axes: LayoutAxes, f: F) -> LayoutResult<ConsistentMap<GenericAxis, E>>
-    where F: Fn(E) -> Option<GenericAxis> {
-        self.0.dedup(|key, &e| {
-            Ok((match key {
-                PosAxisKey::First => f(e).unwrap_or(Primary),
-                PosAxisKey::Second => f(e).unwrap_or(Secondary),
-                PosAxisKey::Keyword(AxisKey::Specific(axis)) => axis.to_generic(axes),
-                PosAxisKey::Keyword(AxisKey::Generic(axis)) => *axis,
-            }, e))
-        })
-    }
-}
diff --git a/src/library/maps/mod.rs b/src/library/maps/mod.rs
deleted file mode 100644
index 3538def7..00000000
--- a/src/library/maps/mod.rs
+++ /dev/null
@@ -1,128 +0,0 @@
-//! Deduplicating maps and keys for argument parsing.
-
-use std::collections::HashMap;
-use std::hash::Hash;
-
-use crate::func::prelude::*;
-
-
-macro_rules! key {
-    ($type:ty, $name:expr, $($patterns:tt)*) => {
-        impl $type {
-            /// Parse this key from an identifier.
-            pub fn from_ident(ident: &Spanned<Ident>) -> ParseResult<Self> {
-                Ok(match ident.v.as_str() {
-                    $($patterns)*
-                    _ => error!("expected {}", <Self as ExpressionKind>::NAME),
-                })
-            }
-        }
-
-        impl ExpressionKind for $type {
-            const NAME: &'static str = $name;
-
-            fn from_expr(expr: Spanned<Expr>) -> ParseResult<Self> {
-                if let Expr::Ident(ident) = expr.v {
-                    Self::from_ident(&Spanned::new(ident, expr.span))
-                } else {
-                    error!("expected {}", Self::NAME);
-                }
-            }
-        }
-    };
-}
-
-pub_use_mod!(axis);
-pub_use_mod!(alignment);
-pub_use_mod!(padding);
-
-
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub enum DefaultKey<T> {
-    Some(T),
-    None,
-}
-
-impl<T> Into<Option<T>> for DefaultKey<T> {
-    fn into(self) -> Option<T> {
-        match self {
-            DefaultKey::Some(v) => Some(v),
-            DefaultKey::None => None,
-        }
-    }
-}
-
-impl<T> ExpressionKind for DefaultKey<T> where T: ExpressionKind {
-    const NAME: &'static str = T::NAME;
-
-    fn from_expr(expr: Spanned<Expr>) -> ParseResult<DefaultKey<T>> {
-        if let Expr::Ident(ident) = &expr.v {
-            match ident.as_str() {
-                "default" => return Ok(DefaultKey::None),
-                _ => {},
-            }
-        }
-
-        T::from_expr(expr).map(|v| DefaultKey::Some(v))
-    }
-}
-
-/// A deduplicating map type useful for storing possibly redundant arguments.
-#[derive(Debug, Clone, PartialEq)]
-pub struct ConsistentMap<K, V> where K: Hash + Eq {
-    map: HashMap<K, V>,
-}
-
-impl<K, V> ConsistentMap<K, V> where K: Hash + Eq {
-    pub fn new() -> ConsistentMap<K, V> {
-        ConsistentMap { map: HashMap::new() }
-    }
-
-    /// Add a key-value pair.
-    pub fn add(&mut self, key: K, value: V) -> ParseResult<()> {
-        match self.map.insert(key, value) {
-            Some(_) => error!("duplicate argument"),
-            None => Ok(())
-        }
-    }
-
-    /// Add a key-value pair if the value is not `None`.
-    pub fn add_opt(&mut self, key: K, value: Option<V>) -> ParseResult<()> {
-        Ok(if let Some(value) = value {
-            self.add(key, value)?;
-        })
-    }
-
-    /// Get the value at a key if it is present.
-    pub fn get(&self, key: K) -> Option<&V> {
-        self.map.get(&key)
-    }
-
-    /// Call a function with the value if the key is present.
-    pub fn with<F>(&self, key: K, callback: F) where F: FnOnce(&V) {
-        if let Some(value) = self.map.get(&key) {
-            callback(value);
-        }
-    }
-
-    /// Create a new consistent map where keys and values are mapped to new keys
-    /// and values.
-    ///
-    /// Returns an error if a new key is duplicate.
-    pub fn dedup<F, K2, V2>(&self, f: F) -> LayoutResult<ConsistentMap<K2, V2>>
-    where F: Fn(&K, &V) -> ParseResult<(K2, V2)>, K2: Hash + Eq {
-        let mut map = ConsistentMap::new();
-
-        for (key, value) in self.map.iter() {
-            let (key, value) = f(key, value)?;
-            map.add(key, value)?;
-        }
-
-        Ok(map)
-    }
-
-    /// Iterate over the (key, value) pairs.
-    pub fn iter(&self) -> std::collections::hash_map::Iter<'_, K, V> {
-        self.map.iter()
-    }
-}
diff --git a/src/library/maps/padding.rs b/src/library/maps/padding.rs
deleted file mode 100644
index e2d0ea09..00000000
--- a/src/library/maps/padding.rs
+++ /dev/null
@@ -1,95 +0,0 @@
-use super::*;
-use AxisKey::*;
-use AlignmentKey::*;
-use PaddingKey::*;
-
-
-/// An argument key which identifies a margin or padding target.
-///
-/// A is the used axis type.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub enum PaddingKey<A> {
-    /// All four sides should have the specified padding.
-    All,
-    /// Both sides of the given axis should have the specified padding.
-    Both(A),
-    /// Only the given side of the given axis should have the specified padding.
-    Side(A, AlignmentKey),
-}
-
-key!(PaddingKey<AxisKey>, "axis or side",
-    "horizontal" | "h" => Both(Specific(Horizontal)),
-    "vertical"   | "v" => Both(Specific(Vertical)),
-    "primary"    | "p" => Both(Generic(Primary)),
-    "secondary"  | "s" => Both(Generic(Secondary)),
-
-    "left"   => Side(Specific(Horizontal), Left),
-    "right"  => Side(Specific(Horizontal), Right),
-    "top"    => Side(Specific(Vertical),   Top),
-    "bottom" => Side(Specific(Vertical),   Bottom),
-
-    "primary-origin"    => Side(Generic(Primary),     Align(Origin)),
-    "primary-end"       => Side(Generic(Primary),     Align(End)),
-    "secondary-origin"  => Side(Generic(Secondary),   Align(Origin)),
-    "secondary-end"     => Side(Generic(Secondary),   Align(End)),
-    "horizontal-origin" => Side(Specific(Horizontal), Align(Origin)),
-    "horizontal-end"    => Side(Specific(Horizontal), Align(End)),
-    "vertical-origin"   => Side(Specific(Vertical),   Align(Origin)),
-    "vertical-end"      => Side(Specific(Vertical),   Align(End)),
-);
-
-/// A map for storing padding at sides.
-#[derive(Debug, Clone, PartialEq)]
-pub struct PaddingMap(ConsistentMap<PaddingKey<AxisKey>, Option<PSize>>);
-
-impl PaddingMap {
-    /// Parse a padding map from the function args.
-    pub fn new(args: &mut FuncArgs) -> ParseResult<PaddingMap> {
-        let mut map = ConsistentMap::new();
-        map.add_opt(PaddingKey::All,
-            args.get_pos_opt::<DefaultKey<PSize>>()?.map(Into::into))?;
-
-        for arg in args.iter_keys() {
-            let key = PaddingKey::from_ident(&arg.key)?;
-            let size = DefaultKey::<PSize>::from_expr(arg.value)?.into();
-            map.add(key, size)?;
-        }
-
-        Ok(PaddingMap(map))
-    }
-
-    /// Apply the specified padding on the size box.
-    pub fn apply(&self, axes: LayoutAxes, padding: &mut ValueBox<Option<PSize>>)
-    -> LayoutResult<()> {
-        use PaddingKey::*;
-
-        let map = self.0.dedup(|key, &val| {
-            Ok((match key {
-                All => All,
-                Both(axis) => Both(axis.to_specific(axes)),
-                Side(axis, alignment) => {
-                    let axis = axis.to_specific(axes);
-                    Side(axis, alignment.to_specific(axes, axis))
-                }
-            }, val))
-        })?;
-
-        map.with(All, |&val| padding.set_all(val));
-        map.with(Both(Horizontal), |&val| padding.set_horizontal(val));
-        map.with(Both(Vertical), |&val| padding.set_vertical(val));
-
-        for (key, &val) in map.iter() {
-            if let Side(_, alignment) = key {
-                match alignment {
-                    AlignmentKey::Left => padding.left = val,
-                    AlignmentKey::Right => padding.right = val,
-                    AlignmentKey::Top => padding.top = val,
-                    AlignmentKey::Bottom => padding.bottom = val,
-                    _ => {},
-                }
-            }
-        }
-
-        Ok(())
-    }
-}
diff --git a/src/library/mod.rs b/src/library/mod.rs
index 8d16ccaf..e706642f 100644
--- a/src/library/mod.rs
+++ b/src/library/mod.rs
@@ -1,34 +1,32 @@
 //! The standard library.
 
-use toddle::query::{FontWeight, FontStyle};
-
 use crate::func::prelude::*;
-use crate::style::{Paper, PaperClass};
-use self::maps::{ExtentMap, PaddingMap, AxisKey};
-
-pub mod maps;
 
-pub_use_mod!(align);
-pub_use_mod!(boxed);
-pub_use_mod!(direction);
+pub_use_mod!(font);
+pub_use_mod!(layout);
+pub_use_mod!(page);
+pub_use_mod!(spacing);
 
 
 /// Create a scope with all standard functions.
 pub fn std() -> Scope {
-    let mut std = Scope::new();
+    let mut std = Scope::new::<ValFunc>();
+
+    // Basics
+    std.add::<ValFunc>("val");
 
     // Font setup
     std.add::<FontFamilyFunc>("font.family");
     std.add::<FontStyleFunc>("font.style");
     std.add::<FontWeightFunc>("font.weight");
     std.add::<FontSizeFunc>("font.size");
+    std.add_with_meta::<ContentSpacingFunc>("word.spacing", ContentKind::Word);
 
     // Layout
+    std.add_with_meta::<ContentSpacingFunc>("line.spacing", ContentKind::Line);
+    std.add_with_meta::<ContentSpacingFunc>("par.spacing", ContentKind::Paragraph);
     std.add::<AlignFunc>("align");
     std.add::<DirectionFunc>("direction");
-    std.add_with_metadata::<ContentSpacingFunc>("par.spacing", ContentKind::Paragraph);
-    std.add_with_metadata::<ContentSpacingFunc>("word.spacing", ContentKind::Word);
-    std.add_with_metadata::<ContentSpacingFunc>("line.spacing", ContentKind::Line);
     std.add::<BoxFunc>("box");
 
     // Spacing
@@ -36,9 +34,9 @@ pub fn std() -> Scope {
     std.add::<LineBreakFunc>("line.break");
     std.add::<ParBreakFunc>("par.break");
     std.add::<PageBreakFunc>("page.break");
-    std.add_with_metadata::<SpacingFunc>("spacing", None);
-    std.add_with_metadata::<SpacingFunc>("h", Some(Horizontal));
-    std.add_with_metadata::<SpacingFunc>("v", Some(Vertical));
+    std.add_with_meta::<SpacingFunc>("spacing", None);
+    std.add_with_meta::<SpacingFunc>("h", Some(Horizontal));
+    std.add_with_meta::<SpacingFunc>("v", Some(Vertical));
 
     // Page setup
     std.add::<PageSizeFunc>("page.size");
@@ -47,331 +45,45 @@ pub fn std() -> Scope {
     std
 }
 
-// -------------------------------------------------------------------------- //
-// Font setup
-
 function! {
-    /// `font.family`: Set the font family.
-    #[derive(Debug, PartialEq)]
-    pub struct FontFamilyFunc {
-        body: Option<SyntaxTree>,
-        list: Vec<String>,
+    /// `val`: Layouts the body with no special effect.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct ValFunc {
+        body: Option<SyntaxModel>,
     }
 
-    parse(header, body, ctx) {
-        FontFamilyFunc {
-            body: parse!(optional: body, ctx),
-            list: {
-                header.args.iter_pos().map(|arg| match arg.v {
-                    Expr::Str(s) |
-                    Expr::Ident(Ident(s)) => Ok(s.to_lowercase()),
-                    _ => error!("expected identifier or string"),
-                }).collect::<LayoutResult<Vec<_>>>()?
-            }
-        }
+    parse(header, body, ctx, errors, decos) {
+        ValFunc { body: body!(opt: body, ctx, errors, decos) }
     }
 
-    layout(self, ctx) {
-        let mut style = ctx.style.text.clone();
-        style.fallback.list = self.list.clone();
-        styled(&self.body, &ctx, style)
-    }
-}
-
-function! {
-    /// `font.style`: Set the font style (normal / italic).
-    #[derive(Debug, PartialEq)]
-    pub struct FontStyleFunc {
-        body: Option<SyntaxTree>,
-        style: FontStyle,
-    }
-
-    parse(header, body, ctx) {
-        FontStyleFunc {
-            body: parse!(optional: body, ctx),
-            style: {
-                let s = header.args.get_pos::<String>()?;
-                match FontStyle::from_str(&s) {
-                    Some(style) => style,
-                    None => error!("invalid font style: `{}`", s),
-                }
-            }
+    layout(self, ctx, errors) {
+        match &self.body {
+            Some(model) => vec![LayoutSyntaxModel(model)],
+            None => vec![],
         }
     }
-
-    layout(self, ctx) {
-        let mut style = ctx.style.text.clone();
-        style.variant.style = self.style;
-        styled(&self.body, &ctx, style)
-    }
 }
 
-function! {
-    /// `font.weight`: Set text with a given weight.
-    #[derive(Debug, PartialEq)]
-    pub struct FontWeightFunc {
-        body: Option<SyntaxTree>,
-        weight: FontWeight,
-    }
-
-    parse(header, body, ctx) {
-        FontWeightFunc {
-            body: parse!(optional: body, ctx),
-            weight: match header.args.get_pos::<Expr>()? {
-                Expr::Number(weight) => {
-                    let weight = weight.round() as i16;
-                    FontWeight(
-                        if weight < 100 { 100 }
-                        else if weight <= 900 { weight }
-                        else { 900 }
-                    )
-                }
-                Expr::Ident(Ident(s)) => {
-                    match FontWeight::from_str(&s) {
-                        Some(weight) => weight,
-                        None => error!("invalid font weight: `{}`", s),
-                    }
-                }
-                _ => error!("expected identifier or number"),
-            },
-        }
-    }
-
-    layout(self, ctx) {
+/// Layout an optional body with a change of the text style.
+fn styled<'a, T, F>(
+    body: &'a Option<SyntaxModel>,
+    ctx: LayoutContext,
+    data: Option<T>,
+    f: F,
+) -> Commands<'a> where F: FnOnce(&mut TextStyle, T) {
+    if let Some(data) = data {
         let mut style = ctx.style.text.clone();
-        style.variant.weight = self.weight;
-        styled(&self.body, &ctx, style)
-    }
-}
-
-function! {
-    /// `font.size`: Sets the font size.
-    #[derive(Debug, PartialEq)]
-    pub struct FontSizeFunc {
-        body: Option<SyntaxTree>,
-        size: ScaleSize,
-    }
-
-    parse(header, body, ctx) {
-        FontSizeFunc {
-            body: parse!(optional: body, ctx),
-            size: header.args.get_pos::<ScaleSize>()?,
+        f(&mut style, data);
+
+        match body {
+            Some(model) => vec![
+                SetTextStyle(style),
+                LayoutSyntaxModel(model),
+                SetTextStyle(ctx.style.text.clone()),
+            ],
+            None => vec![SetTextStyle(style)],
         }
-    }
-
-    layout(self, ctx) {
-        let mut style = ctx.style.text.clone();
-        match self.size {
-            ScaleSize::Absolute(size) => {
-                style.base_font_size = size;
-                style.font_scale = 1.0;
-            }
-            ScaleSize::Scaled(scale) => style.font_scale = scale,
-        }
-        styled(&self.body, &ctx, style)
-    }
-}
-
-// -------------------------------------------------------------------------- //
-// Layout
-
-function! {
-    /// `word.spacing`, `line.spacing`, `par.spacing`: The spacing between
-    /// words, lines or paragraphs as a multiple of the font size.
-    #[derive(Debug, PartialEq)]
-    pub struct ContentSpacingFunc {
-        body: Option<SyntaxTree>,
-        content: ContentKind,
-        spacing: f32,
-    }
-
-    type Meta = ContentKind;
-
-    parse(header, body, ctx, meta) {
-        ContentSpacingFunc {
-            body: parse!(optional: body, ctx),
-            content: meta,
-            spacing: header.args.get_pos::<f64>()? as f32,
-        }
-    }
-
-    layout(self, ctx) {
-        let mut style = ctx.style.text.clone();
-        match self.content {
-            ContentKind::Word => style.word_spacing_scale = self.spacing,
-            ContentKind::Line => style.line_spacing_scale = self.spacing,
-            ContentKind::Paragraph => style.paragraph_spacing_scale = self.spacing,
-        }
-        styled(&self.body, &ctx, style)
-    }
-}
-
-/// The different kinds of content that can be spaced.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-pub enum ContentKind {
-    Word,
-    Line,
-    Paragraph,
-}
-
-// -------------------------------------------------------------------------- //
-// Spacing
-
-function! {
-    /// `line.break`, `n`: Ends the current line.
-    #[derive(Debug, Default, PartialEq)]
-    pub struct LineBreakFunc;
-
-    parse(default)
-    layout() { vec![FinishLine] }
-}
-
-function! {
-    /// `par.break`: Ends the current paragraph.
-    ///
-    /// self has the same effect as two subsequent newlines.
-    #[derive(Debug, Default, PartialEq)]
-    pub struct ParBreakFunc;
-
-    parse(default)
-    layout() { vec![BreakParagraph] }
-}
-
-function! {
-    /// `page.break`: Ends the current page.
-    #[derive(Debug, Default, PartialEq)]
-    pub struct PageBreakFunc;
-
-    parse(default)
-    layout() { vec![BreakPage] }
-}
-
-function! {
-    /// `spacing`, `h`, `v`: Adds spacing along an axis.
-    #[derive(Debug, PartialEq)]
-    pub struct SpacingFunc {
-        axis: AxisKey,
-        spacing: FSize,
-    }
-
-    type Meta = Option<SpecificAxis>;
-
-    parse(header, body, _, meta) {
-        parse!(forbidden: body);
-
-        if let Some(axis) = meta {
-            SpacingFunc {
-                axis: AxisKey::Specific(axis),
-                spacing: FSize::from_expr(
-                    header.args.get_pos::<Spanned<Expr>>()?
-                )?,
-            }
-        } else {
-            for arg in header.args.iter_keys() {
-                let axis = AxisKey::from_ident(&arg.key)
-                    .map_err(|_| error!(@unexpected_argument))?;
-
-                let spacing = FSize::from_expr(arg.value)?;
-                return Ok(SpacingFunc { axis, spacing });
-            }
-
-            error!("expected axis and spacing")
-        }
-    }
-
-    layout(self, ctx) {
-        let axis = self.axis.to_generic(ctx.axes);
-        let spacing = self.spacing.scaled(ctx.style.text.font_size());
-        vec![SpacingFunc(spacing, SpacingKind::Hard, axis)]
-    }
-}
-
-// -------------------------------------------------------------------------- //
-// Page setup
-
-function! {
-    /// `page.size`: Set the size of pages.
-    #[derive(Debug, PartialEq)]
-    pub enum PageSizeFunc {
-        Paper(Paper, bool),
-        Custom(ExtentMap<PSize>),
-    }
-
-    parse(header, body) {
-        parse!(forbidden: body);
-
-        if let Some(name) = header.args.get_pos_opt::<Ident>()? {
-            let flip = header.args.get_key_opt::<bool>("flip")?.unwrap_or(false);
-            let paper = Paper::from_name(name.as_str())
-                .ok_or_else(|| error!(@"invalid paper name: `{}`", name))?;
-            PageSizeFunc::Paper(paper, flip)
-        } else {
-            PageSizeFunc::Custom(ExtentMap::new(&mut header.args, true)?)
-        }
-    }
-
-    layout(self, ctx) {
-        let mut style = ctx.style.page;
-
-        match self {
-            PageSizeFunc::Paper(paper, flip) => {
-                style.class = paper.class;
-                style.dimensions = paper.dimensions;
-                if *flip {
-                    style.dimensions.swap();
-                }
-            }
-
-            PageSizeFunc::Custom(map) => {
-                style.class = PaperClass::Custom;
-
-                let map = map.dedup(ctx.axes)?;
-                let dims = &mut style.dimensions;
-                map.with(Horizontal, |&psize| dims.x = psize.scaled(dims.x));
-                map.with(Vertical, |&psize| dims.y = psize.scaled(dims.y));
-            }
-        }
-
-        vec![SetPageStyle(style)]
-    }
-}
-
-function! {
-    /// `page.margins`: Sets the page margins.
-    #[derive(Debug, PartialEq)]
-    pub struct PageMarginsFunc {
-        map: PaddingMap,
-    }
-
-    parse(header, body) {
-        parse!(forbidden: body);
-        PageMarginsFunc {
-            map: PaddingMap::new(&mut header.args)?,
-        }
-    }
-
-    layout(self, ctx) {
-        let mut style = ctx.style.page;
-        self.map.apply(ctx.axes, &mut style.margins)?;
-        vec![SetPageStyle(style)]
-    }
-}
-
-// -------------------------------------------------------------------------- //
-// Helpers
-
-/// Layout the body with the style or update the style if there is no body.
-fn styled<'a>(
-    body: &'a Option<SyntaxTree>,
-    ctx: &LayoutContext,
-    style: TextStyle
-) -> Commands<'a> {
-    match &body {
-        Some(body) => vec![
-            SetTextStyle(style),
-            LayoutTree(body),
-            SetTextStyle(ctx.style.text.clone()),
-        ],
-        None => vec![SetTextStyle(style)]
+    } else {
+        vec![]
     }
 }
diff --git a/src/library/page.rs b/src/library/page.rs
new file mode 100644
index 00000000..25f81bc1
--- /dev/null
+++ b/src/library/page.rs
@@ -0,0 +1,64 @@
+use crate::style::{Paper, PaperClass};
+use super::*;
+
+
+function! {
+    /// `page.size`: Set the size of pages.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct PageSizeFunc {
+        paper: Option<Paper>,
+        extents: AxisMap<Size>,
+        flip: bool,
+    }
+
+    parse(header, body, ctx, errors, decos) {
+        body!(nope: body, errors);
+        PageSizeFunc {
+            paper: header.args.pos.get::<Paper>(errors),
+            extents: AxisMap::parse::<ExtentKey, Size>(errors, &mut header.args.key),
+            flip: header.args.key.get::<bool>(errors, "flip").unwrap_or(false),
+        }
+    }
+
+    layout(self, ctx, errors) {
+        let mut style = ctx.style.page;
+
+        if let Some(paper) = self.paper {
+            style.class = paper.class;
+            style.dimensions = paper.dimensions;
+        } else {
+            style.class = PaperClass::Custom;
+        }
+
+        let map = self.extents.dedup(errors, ctx.axes);
+        map.with(Horizontal, |&width| style.dimensions.x = width);
+        map.with(Vertical, |&height| style.dimensions.y = height);
+
+        if self.flip {
+            style.dimensions.swap();
+        }
+
+        vec![SetPageStyle(style)]
+    }
+}
+
+function! {
+    /// `page.margins`: Sets the page margins.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct PageMarginsFunc {
+        padding: PaddingMap,
+    }
+
+    parse(header, body, ctx, errors, decos) {
+        body!(nope: body, errors);
+        PageMarginsFunc {
+            padding: PaddingMap::parse(errors, &mut header.args),
+        }
+    }
+
+    layout(self, ctx, errors) {
+        let mut style = ctx.style.page;
+        self.padding.apply(errors, ctx.axes, &mut style.margins);
+        vec![SetPageStyle(style)]
+    }
+}
diff --git a/src/library/spacing.rs b/src/library/spacing.rs
new file mode 100644
index 00000000..6c818292
--- /dev/null
+++ b/src/library/spacing.rs
@@ -0,0 +1,103 @@
+use super::*;
+use ContentKind::*;
+
+
+function! {
+    /// `line.break`, `n`: Ends the current line.
+    #[derive(Debug, Default, Clone, PartialEq)]
+    pub struct LineBreakFunc;
+
+    parse(default)
+    layout(self, ctx, errors) { vec![FinishLine] }
+}
+
+function! {
+    /// `par.break`: Ends the current paragraph.
+    ///
+    /// self has the same effect as two subsequent newlines.
+    #[derive(Debug, Default, Clone, PartialEq)]
+    pub struct ParBreakFunc;
+
+    parse(default)
+    layout(self, ctx, errors) { vec![BreakParagraph] }
+}
+
+function! {
+    /// `page.break`: Ends the current page.
+    #[derive(Debug, Default, Clone, PartialEq)]
+    pub struct PageBreakFunc;
+
+    parse(default)
+    layout(self, ctx, errors) { vec![BreakPage] }
+}
+
+function! {
+    /// `word.spacing`, `line.spacing`, `par.spacing`: The spacing between
+    /// words, lines or paragraphs as a multiple of the font size.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct ContentSpacingFunc {
+        body: Option<SyntaxModel>,
+        content: ContentKind,
+        spacing: Option<f32>,
+    }
+
+    type Meta = ContentKind;
+
+    parse(header, body, ctx, errors, decos, meta) {
+        ContentSpacingFunc {
+            body: body!(opt: body, ctx, errors, decos),
+            content: meta,
+            spacing: header.args.pos.get::<f64>(errors)
+                .map(|num| num as f32)
+                .or_missing(errors, header.name.span, "spacing"),
+        }
+    }
+
+    layout(self, ctx, errors) {
+        styled(&self.body, ctx, self.spacing, |t, s| match self.content {
+            Word => t.word_spacing_scale = s,
+            Line => t.line_spacing_scale = s,
+            Paragraph => t.paragraph_spacing_scale = s,
+        })
+    }
+}
+
+/// The different kinds of content that can be spaced.
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub enum ContentKind {
+    Word,
+    Line,
+    Paragraph,
+}
+
+function! {
+    /// `spacing`, `h`, `v`: Adds spacing along an axis.
+    #[derive(Debug, Clone, PartialEq)]
+    pub struct SpacingFunc {
+        spacing: Option<(AxisKey, FSize)>,
+    }
+
+    type Meta = Option<SpecificAxis>;
+
+    parse(header, body, ctx, errors, decos, meta) {
+        body!(nope: body, errors);
+        SpacingFunc {
+            spacing: if let Some(axis) = meta {
+                header.args.pos.get::<FSize>(errors)
+                    .map(|s| (AxisKey::Specific(axis), s))
+            } else {
+                header.args.key.get_with_key::<AxisKey, FSize>(errors)
+            }.or_missing(errors, header.name.span, "spacing"),
+        }
+    }
+
+    layout(self, ctx, errors) {
+        if let Some((axis, spacing)) = self.spacing {
+            let axis = axis.to_generic(ctx.axes);
+            let spacing = spacing.scaled(ctx.style.text.font_size());
+            vec![AddSpacing(spacing, SpacingKind::Hard, axis)]
+        } else {
+            vec![]
+        }
+    }
+}