Merge eval and layout contexts into `Vm`

33 files changed, 465 insertions, 506 deletions

diff --git a/src/eval/capture.rs b/src/eval/capture.rs
index 8585776a..d62ec55c 100644
--- a/src/eval/capture.rs
+++ b/src/eval/capture.rs
@@ -28,7 +28,7 @@ impl<'a> CapturesVisitor<'a> {
 
     /// Bind a new internal variable.
     pub fn bind(&mut self, ident: Ident) {
-        self.internal.def_mut(ident.take(), Value::None);
+        self.internal.top.def_mut(ident.take(), Value::None);
     }
 
     /// Capture a variable if it isn't internal.
@@ -135,9 +135,9 @@ mod tests {
         let red = RedNode::from_root(green, SourceId::from_raw(0));
 
         let mut scopes = Scopes::new(None);
-        scopes.def_const("x", 0);
-        scopes.def_const("y", 0);
-        scopes.def_const("z", 0);
+        scopes.top.def_const("x", 0);
+        scopes.top.def_const("y", 0);
+        scopes.top.def_const("z", 0);
 
         let mut visitor = CapturesVisitor::new(&scopes);
         visitor.visit(red.as_ref());
diff --git a/src/eval/class.rs b/src/eval/class.rs
index c4880e9a..28e49a99 100644
--- a/src/eval/class.rs
+++ b/src/eval/class.rs
@@ -1,7 +1,7 @@
 use std::fmt::{self, Debug, Formatter, Write};
 use std::hash::{Hash, Hasher};
 
-use super::{Args, EvalContext, Func, StyleMap, Template, Value};
+use super::{Args, Func, StyleMap, Template, Value, Vm};
 use crate::diag::TypResult;
 
 /// A class of nodes.
@@ -36,7 +36,7 @@ use crate::diag::TypResult;
 #[derive(Clone)]
 pub struct Class {
     name: &'static str,
-    construct: fn(&mut EvalContext, &mut Args) -> TypResult<Value>,
+    construct: fn(&mut Vm, &mut Args) -> TypResult<Value>,
     set: fn(&mut Args, &mut StyleMap) -> TypResult<()>,
 }
 
@@ -73,8 +73,8 @@ impl Class {
     /// This parses both property and data arguments (in this order), styles the
     /// template constructed from the data with the style properties and wraps
     /// it in a value.
-    pub fn construct(&self, ctx: &mut EvalContext, mut args: Args) -> TypResult<Value> {
-        let value = (self.construct)(ctx, &mut args)?;
+    pub fn construct(&self, vm: &mut Vm, mut args: Args) -> TypResult<Value> {
+        let value = (self.construct)(vm, &mut args)?;
         args.finish()?;
         Ok(value)
     }
@@ -117,7 +117,7 @@ pub trait Construct {
     ///
     /// This is passed only the arguments that remain after execution of the
     /// class's set rule.
-    fn construct(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Template>;
+    fn construct(vm: &mut Vm, args: &mut Args) -> TypResult<Template>;
 }
 
 /// Set style properties of a class.
diff --git a/src/eval/func.rs b/src/eval/func.rs
index a4a733b3..9a8a9c94 100644
--- a/src/eval/func.rs
+++ b/src/eval/func.rs
@@ -2,7 +2,7 @@ use std::fmt::{self, Debug, Formatter, Write};
 use std::hash::{Hash, Hasher};
 use std::sync::Arc;
 
-use super::{Cast, Eval, EvalContext, Scope, Value};
+use super::{Cast, Eval, Scope, Value, Vm};
 use crate::diag::{At, TypResult};
 use crate::syntax::ast::Expr;
 use crate::syntax::{Span, Spanned};
@@ -27,7 +27,7 @@ impl Func {
     /// Create a new function from a native rust function.
     pub fn native(
         name: &'static str,
-        func: fn(&mut EvalContext, &mut Args) -> TypResult<Value>,
+        func: fn(&mut Vm, &mut Args) -> TypResult<Value>,
     ) -> Self {
         Self(Arc::new(Repr::Native(Native { name, func })))
     }
@@ -47,13 +47,13 @@ impl Func {
     }
 
     /// Call the function in the context with the arguments.
-    pub fn call(&self, ctx: &mut EvalContext, mut args: Args) -> TypResult<Value> {
+    pub fn call(&self, vm: &mut Vm, mut args: Args) -> TypResult<Value> {
         let value = match self.0.as_ref() {
-            Repr::Native(native) => (native.func)(ctx, &mut args)?,
-            Repr::Closure(closure) => closure.call(ctx, &mut args)?,
+            Repr::Native(native) => (native.func)(vm, &mut args)?,
+            Repr::Closure(closure) => closure.call(vm, &mut args)?,
             Repr::With(wrapped, applied) => {
                 args.items.splice(.. 0, applied.items.iter().cloned());
-                return wrapped.call(ctx, args);
+                return wrapped.call(vm, args);
             }
         };
         args.finish()?;
@@ -88,7 +88,7 @@ struct Native {
     /// The name of the function.
     pub name: &'static str,
     /// The function pointer.
-    pub func: fn(&mut EvalContext, &mut Args) -> TypResult<Value>,
+    pub func: fn(&mut Vm, &mut Args) -> TypResult<Value>,
 }
 
 impl Hash for Native {
@@ -115,15 +115,15 @@ pub struct Closure {
 
 impl Closure {
     /// Call the function in the context with the arguments.
-    pub fn call(&self, ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+    pub fn call(&self, vm: &mut Vm, args: &mut Args) -> TypResult<Value> {
         // Don't leak the scopes from the call site. Instead, we use the
         // scope of captured variables we collected earlier.
-        let prev_scopes = std::mem::take(&mut ctx.scopes);
-        ctx.scopes.top = self.captured.clone();
+        let prev_scopes = std::mem::take(&mut vm.scopes);
+        vm.scopes.top = self.captured.clone();
 
         // Parse the arguments according to the parameter list.
         for (param, default) in &self.params {
-            ctx.scopes.def_mut(param, match default {
+            vm.scopes.top.def_mut(param, match default {
                 None => args.expect::<Value>(param)?,
                 Some(default) => {
                     args.named::<Value>(param)?.unwrap_or_else(|| default.clone())
@@ -133,14 +133,14 @@ impl Closure {
 
         // Put the remaining arguments into the sink.
         if let Some(sink) = &self.sink {
-            ctx.scopes.def_mut(sink, args.take());
+            vm.scopes.top.def_mut(sink, args.take());
         }
 
         // Evaluate the body.
-        let value = self.body.eval(ctx)?;
+        let value = self.body.eval(vm)?;
 
         // Restore the call site scopes.
-        ctx.scopes = prev_scopes;
+        vm.scopes = prev_scopes;
 
         Ok(value)
     }
diff --git a/src/eval/mod.rs b/src/eval/mod.rs
index 5f339bc8..98f84082 100644
--- a/src/eval/mod.rs
+++ b/src/eval/mod.rs
@@ -29,24 +29,19 @@ pub use styles::*;
 pub use template::*;
 pub use value::*;
 
-use std::collections::HashMap;
 use std::io;
 use std::mem;
-use std::path::PathBuf;
 
 use unicode_segmentation::UnicodeSegmentation;
 
 use crate::diag::{At, Error, StrResult, Trace, Tracepoint, TypResult};
 use crate::geom::{Angle, Fractional, Length, Relative};
-use crate::image::ImageStore;
 use crate::layout::Layout;
 use crate::library::{self, ORDERED, UNORDERED};
-use crate::loading::Loader;
-use crate::source::{SourceId, SourceStore};
 use crate::syntax::ast::*;
 use crate::syntax::{Span, Spanned};
 use crate::util::EcoString;
-use crate::Context;
+use crate::Vm;
 
 /// An evaluated module, ready for importing or conversion to a root layout
 /// tree.
@@ -64,106 +59,20 @@ pub trait Eval {
     type Output;
 
     /// Evaluate the expression to the output value.
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output>;
-}
-
-/// The context for evaluation.
-pub struct EvalContext<'a> {
-    /// The loader from which resources (files and images) are loaded.
-    pub loader: &'a dyn Loader,
-    /// Stores loaded source files.
-    pub sources: &'a mut SourceStore,
-    /// Stores decoded images.
-    pub images: &'a mut ImageStore,
-    /// The stack of imported files that led to evaluation of the current file.
-    pub route: Vec<SourceId>,
-    /// Caches imported modules.
-    pub modules: HashMap<SourceId, Module>,
-    /// The active scopes.
-    pub scopes: Scopes<'a>,
-}
-
-impl<'a> EvalContext<'a> {
-    /// Create a new evaluation context.
-    pub fn new(ctx: &'a mut Context, source: SourceId) -> Self {
-        Self {
-            loader: ctx.loader.as_ref(),
-            sources: &mut ctx.sources,
-            images: &mut ctx.images,
-            route: vec![source],
-            modules: HashMap::new(),
-            scopes: Scopes::new(Some(&ctx.std)),
-        }
-    }
-
-    /// Process an import of a module relative to the current location.
-    pub fn import(&mut self, path: &str, span: Span) -> TypResult<SourceId> {
-        // Load the source file.
-        let full = self.make_path(path);
-        let id = self.sources.load(&full).map_err(|err| {
-            Error::boxed(span, match err.kind() {
-                io::ErrorKind::NotFound => "file not found".into(),
-                _ => format!("failed to load source file ({})", err),
-            })
-        })?;
-
-        // Prevent cyclic importing.
-        if self.route.contains(&id) {
-            bail!(span, "cyclic import");
-        }
-
-        // Check whether the module was already loaded.
-        if self.modules.get(&id).is_some() {
-            return Ok(id);
-        }
-
-        // Parse the file.
-        let source = self.sources.get(id);
-        let ast = source.ast()?;
-
-        // Prepare the new context.
-        let new_scopes = Scopes::new(self.scopes.base);
-        let prev_scopes = mem::replace(&mut self.scopes, new_scopes);
-        self.route.push(id);
-
-        // Evaluate the module.
-        let template = ast.eval(self).trace(|| Tracepoint::Import, span)?;
-
-        // Restore the old context.
-        let new_scopes = mem::replace(&mut self.scopes, prev_scopes);
-        self.route.pop().unwrap();
-
-        // Save the evaluated module.
-        let module = Module { scope: new_scopes.top, template };
-        self.modules.insert(id, module);
-
-        Ok(id)
-    }
-
-    /// Complete a user-entered path (relative to the source file) to be
-    /// relative to the compilation environment's root.
-    pub fn make_path(&self, path: &str) -> PathBuf {
-        if let Some(&id) = self.route.last() {
-            if let Some(dir) = self.sources.get(id).path().parent() {
-                return dir.join(path);
-            }
-        }
-
-        path.into()
-    }
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output>;
 }
 
 impl Eval for Markup {
     type Output = Template;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        eval_markup(ctx, &mut self.nodes())
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        eval_markup(vm, &mut self.nodes())
     }
 }
 
 /// Evaluate a stream of markup nodes.
 fn eval_markup(
-    ctx: &mut EvalContext,
+    vm: &mut Vm,
     nodes: &mut impl Iterator<Item = MarkupNode>,
 ) -> TypResult<Template> {
     let mut seq = Vec::with_capacity(nodes.size_hint().1.unwrap_or_default());
@@ -172,21 +81,21 @@ fn eval_markup(
         seq.push(match node {
             MarkupNode::Expr(Expr::Set(set)) => {
                 let class = set.class();
-                let class = class.eval(ctx)?.cast::<Class>().at(class.span())?;
-                let args = set.args().eval(ctx)?;
+                let class = class.eval(vm)?.cast::<Class>().at(class.span())?;
+                let args = set.args().eval(vm)?;
                 let styles = class.set(args)?;
-                let tail = eval_markup(ctx, nodes)?;
+                let tail = eval_markup(vm, nodes)?;
                 tail.styled_with_map(styles)
             }
             MarkupNode::Expr(Expr::Show(show)) => {
                 return Err("show rules are not yet implemented").at(show.span());
             }
             MarkupNode::Expr(Expr::Wrap(wrap)) => {
-                let tail = eval_markup(ctx, nodes)?;
-                ctx.scopes.def_mut(wrap.binding().take(), tail);
-                wrap.body().eval(ctx)?.display()
+                let tail = eval_markup(vm, nodes)?;
+                vm.scopes.top.def_mut(wrap.binding().take(), tail);
+                wrap.body().eval(vm)?.display()
             }
-            _ => node.eval(ctx)?,
+            _ => node.eval(vm)?,
         });
     }
 
@@ -196,20 +105,20 @@ fn eval_markup(
 impl Eval for MarkupNode {
     type Output = Template;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         Ok(match self {
             Self::Space => Template::Space,
             Self::Linebreak => Template::Linebreak,
             Self::Parbreak => Template::Parbreak,
             Self::Text(text) => Template::Text(text.clone()),
-            Self::Strong(strong) => strong.eval(ctx)?,
-            Self::Emph(emph) => emph.eval(ctx)?,
-            Self::Raw(raw) => raw.eval(ctx)?,
-            Self::Math(math) => math.eval(ctx)?,
-            Self::Heading(heading) => heading.eval(ctx)?,
-            Self::List(list) => list.eval(ctx)?,
-            Self::Enum(enum_) => enum_.eval(ctx)?,
-            Self::Expr(expr) => expr.eval(ctx)?.display(),
+            Self::Strong(strong) => strong.eval(vm)?,
+            Self::Emph(emph) => emph.eval(vm)?,
+            Self::Raw(raw) => raw.eval(vm)?,
+            Self::Math(math) => math.eval(vm)?,
+            Self::Heading(heading) => heading.eval(vm)?,
+            Self::List(list) => list.eval(vm)?,
+            Self::Enum(enum_) => enum_.eval(vm)?,
+            Self::Expr(expr) => expr.eval(vm)?.display(),
         })
     }
 }
@@ -217,23 +126,23 @@ impl Eval for MarkupNode {
 impl Eval for StrongNode {
     type Output = Template;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        Ok(Template::show(library::StrongNode(self.body().eval(ctx)?)))
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        Ok(Template::show(library::StrongNode(self.body().eval(vm)?)))
     }
 }
 
 impl Eval for EmphNode {
     type Output = Template;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        Ok(Template::show(library::EmphNode(self.body().eval(ctx)?)))
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        Ok(Template::show(library::EmphNode(self.body().eval(vm)?)))
     }
 }
 
 impl Eval for RawNode {
     type Output = Template;
 
-    fn eval(&self, _: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, _: &mut Vm) -> TypResult<Self::Output> {
         let template = Template::show(library::RawNode {
             text: self.text.clone(),
             block: self.block,
@@ -248,7 +157,7 @@ impl Eval for RawNode {
 impl Eval for MathNode {
     type Output = Template;
 
-    fn eval(&self, _: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, _: &mut Vm) -> TypResult<Self::Output> {
         Ok(Template::show(library::MathNode {
             formula: self.formula.clone(),
             display: self.display,
@@ -259,9 +168,9 @@ impl Eval for MathNode {
 impl Eval for HeadingNode {
     type Output = Template;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         Ok(Template::show(library::HeadingNode {
-            body: self.body().eval(ctx)?,
+            body: self.body().eval(vm)?,
             level: self.level(),
         }))
     }
@@ -270,10 +179,10 @@ impl Eval for HeadingNode {
 impl Eval for ListNode {
     type Output = Template;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         Ok(Template::show(library::ListNode::<UNORDERED> {
             number: None,
-            child: self.body().eval(ctx)?.pack(),
+            child: self.body().eval(vm)?.pack(),
         }))
     }
 }
@@ -281,10 +190,10 @@ impl Eval for ListNode {
 impl Eval for EnumNode {
     type Output = Template;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         Ok(Template::show(library::ListNode::<ORDERED> {
             number: self.number(),
-            child: self.body().eval(ctx)?.pack(),
+            child: self.body().eval(vm)?.pack(),
         }))
     }
 }
@@ -292,32 +201,32 @@ impl Eval for EnumNode {
 impl Eval for Expr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         match self {
-            Self::Lit(v) => v.eval(ctx),
-            Self::Ident(v) => v.eval(ctx),
-            Self::Array(v) => v.eval(ctx).map(Value::Array),
-            Self::Dict(v) => v.eval(ctx).map(Value::Dict),
-            Self::Template(v) => v.eval(ctx).map(Value::Template),
-            Self::Group(v) => v.eval(ctx),
-            Self::Block(v) => v.eval(ctx),
-            Self::Call(v) => v.eval(ctx),
-            Self::Closure(v) => v.eval(ctx),
-            Self::With(v) => v.eval(ctx),
-            Self::Unary(v) => v.eval(ctx),
-            Self::Binary(v) => v.eval(ctx),
-            Self::Let(v) => v.eval(ctx),
-            Self::Set(v) => v.eval(ctx),
-            Self::Show(v) => v.eval(ctx),
-            Self::Wrap(v) => v.eval(ctx),
-            Self::If(v) => v.eval(ctx),
-            Self::While(v) => v.eval(ctx),
-            Self::For(v) => v.eval(ctx),
-            Self::Import(v) => v.eval(ctx),
-            Self::Include(v) => v.eval(ctx),
-            Self::Break(v) => v.eval(ctx),
-            Self::Continue(v) => v.eval(ctx),
-            Self::Return(v) => v.eval(ctx),
+            Self::Lit(v) => v.eval(vm),
+            Self::Ident(v) => v.eval(vm),
+            Self::Array(v) => v.eval(vm).map(Value::Array),
+            Self::Dict(v) => v.eval(vm).map(Value::Dict),
+            Self::Template(v) => v.eval(vm).map(Value::Template),
+            Self::Group(v) => v.eval(vm),
+            Self::Block(v) => v.eval(vm),
+            Self::Call(v) => v.eval(vm),
+            Self::Closure(v) => v.eval(vm),
+            Self::With(v) => v.eval(vm),
+            Self::Unary(v) => v.eval(vm),
+            Self::Binary(v) => v.eval(vm),
+            Self::Let(v) => v.eval(vm),
+            Self::Set(v) => v.eval(vm),
+            Self::Show(v) => v.eval(vm),
+            Self::Wrap(v) => v.eval(vm),
+            Self::If(v) => v.eval(vm),
+            Self::While(v) => v.eval(vm),
+            Self::For(v) => v.eval(vm),
+            Self::Import(v) => v.eval(vm),
+            Self::Include(v) => v.eval(vm),
+            Self::Break(v) => v.eval(vm),
+            Self::Continue(v) => v.eval(vm),
+            Self::Return(v) => v.eval(vm),
         }
     }
 }
@@ -325,7 +234,7 @@ impl Eval for Expr {
 impl Eval for Lit {
     type Output = Value;
 
-    fn eval(&self, _: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, _: &mut Vm) -> TypResult<Self::Output> {
         Ok(match self.kind() {
             LitKind::None => Value::None,
             LitKind::Auto => Value::Auto,
@@ -344,8 +253,8 @@ impl Eval for Lit {
 impl Eval for Ident {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        match ctx.scopes.get(self) {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        match vm.scopes.get(self) {
             Some(slot) => Ok(slot.read().unwrap().clone()),
             None => bail!(self.span(), "unknown variable"),
         }
@@ -355,17 +264,17 @@ impl Eval for Ident {
 impl Eval for ArrayExpr {
     type Output = Array;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        self.items().map(|expr| expr.eval(ctx)).collect()
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        self.items().map(|expr| expr.eval(vm)).collect()
     }
 }
 
 impl Eval for DictExpr {
     type Output = Dict;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         self.items()
-            .map(|x| Ok((x.name().take(), x.expr().eval(ctx)?)))
+            .map(|x| Ok((x.name().take(), x.expr().eval(vm)?)))
             .collect()
     }
 }
@@ -373,10 +282,10 @@ impl Eval for DictExpr {
 impl Eval for TemplateExpr {
     type Output = Template;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        ctx.scopes.enter();
-        let template = self.body().eval(ctx)?;
-        ctx.scopes.exit();
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        vm.scopes.enter();
+        let template = self.body().eval(vm)?;
+        vm.scopes.exit();
         Ok(template)
     }
 }
@@ -384,24 +293,24 @@ impl Eval for TemplateExpr {
 impl Eval for GroupExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        self.expr().eval(ctx)
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        self.expr().eval(vm)
     }
 }
 
 impl Eval for BlockExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        ctx.scopes.enter();
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        vm.scopes.enter();
 
         let mut output = Value::None;
         for expr in self.exprs() {
-            let value = expr.eval(ctx)?;
+            let value = expr.eval(vm)?;
             output = ops::join(output, value).at(expr.span())?;
         }
 
-        ctx.scopes.exit();
+        vm.scopes.exit();
 
         Ok(output)
     }
@@ -410,8 +319,8 @@ impl Eval for BlockExpr {
 impl Eval for UnaryExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        let value = self.expr().eval(ctx)?;
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        let value = self.expr().eval(vm)?;
         let result = match self.op() {
             UnOp::Pos => ops::pos(value),
             UnOp::Neg => ops::neg(value),
@@ -424,25 +333,25 @@ impl Eval for UnaryExpr {
 impl Eval for BinaryExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         match self.op() {
-            BinOp::Add => self.apply(ctx, ops::add),
-            BinOp::Sub => self.apply(ctx, ops::sub),
-            BinOp::Mul => self.apply(ctx, ops::mul),
-            BinOp::Div => self.apply(ctx, ops::div),
-            BinOp::And => self.apply(ctx, ops::and),
-            BinOp::Or => self.apply(ctx, ops::or),
-            BinOp::Eq => self.apply(ctx, ops::eq),
-            BinOp::Neq => self.apply(ctx, ops::neq),
-            BinOp::Lt => self.apply(ctx, ops::lt),
-            BinOp::Leq => self.apply(ctx, ops::leq),
-            BinOp::Gt => self.apply(ctx, ops::gt),
-            BinOp::Geq => self.apply(ctx, ops::geq),
-            BinOp::Assign => self.assign(ctx, |_, b| Ok(b)),
-            BinOp::AddAssign => self.assign(ctx, ops::add),
-            BinOp::SubAssign => self.assign(ctx, ops::sub),
-            BinOp::MulAssign => self.assign(ctx, ops::mul),
-            BinOp::DivAssign => self.assign(ctx, ops::div),
+            BinOp::Add => self.apply(vm, ops::add),
+            BinOp::Sub => self.apply(vm, ops::sub),
+            BinOp::Mul => self.apply(vm, ops::mul),
+            BinOp::Div => self.apply(vm, ops::div),
+            BinOp::And => self.apply(vm, ops::and),
+            BinOp::Or => self.apply(vm, ops::or),
+            BinOp::Eq => self.apply(vm, ops::eq),
+            BinOp::Neq => self.apply(vm, ops::neq),
+            BinOp::Lt => self.apply(vm, ops::lt),
+            BinOp::Leq => self.apply(vm, ops::leq),
+            BinOp::Gt => self.apply(vm, ops::gt),
+            BinOp::Geq => self.apply(vm, ops::geq),
+            BinOp::Assign => self.assign(vm, |_, b| Ok(b)),
+            BinOp::AddAssign => self.assign(vm, ops::add),
+            BinOp::SubAssign => self.assign(vm, ops::sub),
+            BinOp::MulAssign => self.assign(vm, ops::mul),
+            BinOp::DivAssign => self.assign(vm, ops::div),
         }
     }
 }
@@ -451,10 +360,10 @@ impl BinaryExpr {
     /// Apply a basic binary operation.
     fn apply(
         &self,
-        ctx: &mut EvalContext,
+        vm: &mut Vm,
         op: fn(Value, Value) -> StrResult<Value>,
     ) -> TypResult<Value> {
-        let lhs = self.lhs().eval(ctx)?;
+        let lhs = self.lhs().eval(vm)?;
 
         // Short-circuit boolean operations.
         if (self.op() == BinOp::And && lhs == Value::Bool(false))
@@ -463,19 +372,19 @@ impl BinaryExpr {
             return Ok(lhs);
         }
 
-        let rhs = self.rhs().eval(ctx)?;
+        let rhs = self.rhs().eval(vm)?;
         op(lhs, rhs).at(self.span())
     }
 
     /// Apply an assignment operation.
     fn assign(
         &self,
-        ctx: &mut EvalContext,
+        vm: &mut Vm,
         op: fn(Value, Value) -> StrResult<Value>,
     ) -> TypResult<Value> {
-        let rhs = self.rhs().eval(ctx)?;
+        let rhs = self.rhs().eval(vm)?;
         self.lhs().access(
-            ctx,
+            vm,
             Box::new(|target| {
                 let lhs = mem::take(&mut *target);
                 *target = op(lhs, rhs).at(self.span())?;
@@ -489,10 +398,10 @@ impl BinaryExpr {
 impl Eval for CallExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         let span = self.callee().span();
-        let callee = self.callee().eval(ctx)?;
-        let args = self.args().eval(ctx)?;
+        let callee = self.callee().eval(vm)?;
+        let args = self.args().eval(vm)?;
 
         match callee {
             Value::Array(array) => {
@@ -505,12 +414,12 @@ impl Eval for CallExpr {
 
             Value::Func(func) => {
                 let point = || Tracepoint::Call(func.name().map(ToString::to_string));
-                func.call(ctx, args).trace(point, self.span())
+                func.call(vm, args).trace(point, self.span())
             }
 
             Value::Class(class) => {
                 let point = || Tracepoint::Call(Some(class.name().to_string()));
-                class.construct(ctx, args).trace(point, self.span())
+                class.construct(vm, args).trace(point, self.span())
             }
 
             v => bail!(
@@ -525,7 +434,7 @@ impl Eval for CallExpr {
 impl Eval for CallArgs {
     type Output = Args;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         let mut items = Vec::new();
 
         for arg in self.items() {
@@ -535,17 +444,17 @@ impl Eval for CallArgs {
                     items.push(Arg {
                         span,
                         name: None,
-                        value: Spanned::new(expr.eval(ctx)?, expr.span()),
+                        value: Spanned::new(expr.eval(vm)?, expr.span()),
                     });
                 }
                 CallArg::Named(named) => {
                     items.push(Arg {
                         span,
                         name: Some(named.name().take()),
-                        value: Spanned::new(named.expr().eval(ctx)?, named.expr().span()),
+                        value: Spanned::new(named.expr().eval(vm)?, named.expr().span()),
                     });
                 }
-                CallArg::Spread(expr) => match expr.eval(ctx)? {
+                CallArg::Spread(expr) => match expr.eval(vm)? {
                     Value::None => {}
                     Value::Array(array) => {
                         items.extend(array.into_iter().map(|value| Arg {
@@ -574,13 +483,13 @@ impl Eval for CallArgs {
 impl Eval for ClosureExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         // The closure's name is defined by its let binding if there's one.
         let name = self.name().map(Ident::take);
 
         // Collect captured variables.
         let captured = {
-            let mut visitor = CapturesVisitor::new(&ctx.scopes);
+            let mut visitor = CapturesVisitor::new(&vm.scopes);
             visitor.visit(self.as_red());
             visitor.finish()
         };
@@ -595,7 +504,7 @@ impl Eval for ClosureExpr {
                     params.push((name.take(), None));
                 }
                 ClosureParam::Named(named) => {
-                    params.push((named.name().take(), Some(named.expr().eval(ctx)?)));
+                    params.push((named.name().take(), Some(named.expr().eval(vm)?)));
                 }
                 ClosureParam::Sink(name) => {
                     if sink.is_some() {
@@ -620,10 +529,10 @@ impl Eval for ClosureExpr {
 impl Eval for WithExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         let callee = self.callee();
-        let func = callee.eval(ctx)?.cast::<Func>().at(callee.span())?;
-        let args = self.args().eval(ctx)?;
+        let func = callee.eval(vm)?.cast::<Func>().at(callee.span())?;
+        let args = self.args().eval(vm)?;
         Ok(Value::Func(func.with(args)))
     }
 }
@@ -631,12 +540,12 @@ impl Eval for WithExpr {
 impl Eval for LetExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         let value = match self.init() {
-            Some(expr) => expr.eval(ctx)?,
+            Some(expr) => expr.eval(vm)?,
             None => Value::None,
         };
-        ctx.scopes.def_mut(self.binding().take(), value);
+        vm.scopes.top.def_mut(self.binding().take(), value);
         Ok(Value::None)
     }
 }
@@ -644,7 +553,7 @@ impl Eval for LetExpr {
 impl Eval for SetExpr {
     type Output = Value;
 
-    fn eval(&self, _: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, _: &mut Vm) -> TypResult<Self::Output> {
         Err("set is only allowed directly in markup").at(self.span())
     }
 }
@@ -652,7 +561,7 @@ impl Eval for SetExpr {
 impl Eval for ShowExpr {
     type Output = Value;
 
-    fn eval(&self, _: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, _: &mut Vm) -> TypResult<Self::Output> {
         Err("show is only allowed directly in markup").at(self.span())
     }
 }
@@ -660,7 +569,7 @@ impl Eval for ShowExpr {
 impl Eval for WrapExpr {
     type Output = Value;
 
-    fn eval(&self, _: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, _: &mut Vm) -> TypResult<Self::Output> {
         Err("wrap is only allowed directly in markup").at(self.span())
     }
 }
@@ -668,12 +577,12 @@ impl Eval for WrapExpr {
 impl Eval for IfExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         let condition = self.condition();
-        if condition.eval(ctx)?.cast::<bool>().at(condition.span())? {
-            self.if_body().eval(ctx)
+        if condition.eval(vm)?.cast::<bool>().at(condition.span())? {
+            self.if_body().eval(vm)
         } else if let Some(else_body) = self.else_body() {
-            else_body.eval(ctx)
+            else_body.eval(vm)
         } else {
             Ok(Value::None)
         }
@@ -683,13 +592,13 @@ impl Eval for IfExpr {
 impl Eval for WhileExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         let mut output = Value::None;
 
         let condition = self.condition();
-        while condition.eval(ctx)?.cast::<bool>().at(condition.span())? {
+        while condition.eval(vm)?.cast::<bool>().at(condition.span())? {
             let body = self.body();
-            let value = body.eval(ctx)?;
+            let value = body.eval(vm)?;
             output = ops::join(output, value).at(body.span())?;
         }
 
@@ -700,27 +609,27 @@ impl Eval for WhileExpr {
 impl Eval for ForExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
         macro_rules! iter {
             (for ($($binding:ident => $value:ident),*) in $iter:expr) => {{
                 let mut output = Value::None;
-                ctx.scopes.enter();
+                vm.scopes.enter();
 
                 #[allow(unused_parens)]
                 for ($($value),*) in $iter {
-                    $(ctx.scopes.def_mut(&$binding, $value);)*
+                    $(vm.scopes.top.def_mut(&$binding, $value);)*
 
-                    let value = self.body().eval(ctx)?;
+                    let value = self.body().eval(vm)?;
                     output = ops::join(output, value)
                         .at(self.body().span())?;
                 }
 
-                ctx.scopes.exit();
+                vm.scopes.exit();
                 return Ok(output);
             }};
         }
 
-        let iter = self.iter().eval(ctx)?;
+        let iter = self.iter().eval(vm)?;
         let pattern = self.pattern();
         let key = pattern.key().map(Ident::take);
         let value = pattern.value().take();
@@ -763,22 +672,21 @@ impl Eval for ForExpr {
 impl Eval for ImportExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        let path = self.path();
-        let resolved = path.eval(ctx)?.cast::<EcoString>().at(path.span())?;
-        let file = ctx.import(&resolved, path.span())?;
-        let module = &ctx.modules[&file];
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        let span = self.path().span();
+        let path = self.path().eval(vm)?.cast::<EcoString>().at(span)?;
+        let module = import(vm, &path, span)?;
 
         match self.imports() {
             Imports::Wildcard => {
                 for (var, slot) in module.scope.iter() {
-                    ctx.scopes.def_mut(var, slot.read().unwrap().clone());
+                    vm.scopes.top.def_mut(var, slot.read().unwrap().clone());
                 }
             }
             Imports::Items(idents) => {
                 for ident in idents {
                     if let Some(slot) = module.scope.get(&ident) {
-                        ctx.scopes.def_mut(ident.take(), slot.read().unwrap().clone());
+                        vm.scopes.top.def_mut(ident.take(), slot.read().unwrap().clone());
                     } else {
                         bail!(ident.span(), "unresolved import");
                     }
@@ -793,19 +701,38 @@ impl Eval for ImportExpr {
 impl Eval for IncludeExpr {
     type Output = Value;
 
-    fn eval(&self, ctx: &mut EvalContext) -> TypResult<Self::Output> {
-        let path = self.path();
-        let resolved = path.eval(ctx)?.cast::<EcoString>().at(path.span())?;
-        let file = ctx.import(&resolved, path.span())?;
-        let module = &ctx.modules[&file];
+    fn eval(&self, vm: &mut Vm) -> TypResult<Self::Output> {
+        let span = self.path().span();
+        let path = self.path().eval(vm)?.cast::<EcoString>().at(span)?;
+        let module = import(vm, &path, span)?;
         Ok(Value::Template(module.template.clone()))
     }
 }
 
+/// Process an import of a module relative to the current location.
+fn import(vm: &mut Vm, path: &str, span: Span) -> TypResult<Module> {
+    // Load the source file.
+    let full = vm.resolve(path);
+    let id = vm.sources.load(&full).map_err(|err| {
+        Error::boxed(span, match err.kind() {
+            io::ErrorKind::NotFound => "file not found".into(),
+            _ => format!("failed to load source file ({})", err),
+        })
+    })?;
+
+    // Prevent cyclic importing.
+    if vm.route.contains(&id) {
+        bail!(span, "cyclic import");
+    }
+
+    // Evaluate the file.
+    vm.evaluate(id).trace(|| Tracepoint::Import, span)
+}
+
 impl Eval for BreakExpr {
     type Output = Value;
 
-    fn eval(&self, _: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, _: &mut Vm) -> TypResult<Self::Output> {
         Err("break is not yet implemented").at(self.span())
     }
 }
@@ -813,7 +740,7 @@ impl Eval for BreakExpr {
 impl Eval for ContinueExpr {
     type Output = Value;
 
-    fn eval(&self, _: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, _: &mut Vm) -> TypResult<Self::Output> {
         Err("continue is not yet implemented").at(self.span())
     }
 }
@@ -821,7 +748,7 @@ impl Eval for ContinueExpr {
 impl Eval for ReturnExpr {
     type Output = Value;
 
-    fn eval(&self, _: &mut EvalContext) -> TypResult<Self::Output> {
+    fn eval(&self, _: &mut Vm) -> TypResult<Self::Output> {
         Err("return is not yet implemented").at(self.span())
     }
 }
@@ -831,25 +758,25 @@ impl Eval for ReturnExpr {
 /// This only works if the expression is a valid lvalue.
 pub trait Access {
     /// Try to access the value.
-    fn access(&self, ctx: &mut EvalContext, f: Handler) -> TypResult<()>;
+    fn access(&self, vm: &mut Vm, f: Handler) -> TypResult<()>;
 }
 
 /// Process an accessed value.
 type Handler<'a> = Box<dyn FnOnce(&mut Value) -> TypResult<()> + 'a>;
 
 impl Access for Expr {
-    fn access(&self, ctx: &mut EvalContext, f: Handler) -> TypResult<()> {
+    fn access(&self, vm: &mut Vm, f: Handler) -> TypResult<()> {
         match self {
-            Expr::Ident(ident) => ident.access(ctx, f),
-            Expr::Call(call) => call.access(ctx, f),
+            Expr::Ident(ident) => ident.access(vm, f),
+            Expr::Call(call) => call.access(vm, f),
             _ => bail!(self.span(), "cannot access this expression mutably"),
         }
     }
 }
 
 impl Access for Ident {
-    fn access(&self, ctx: &mut EvalContext, f: Handler) -> TypResult<()> {
-        match ctx.scopes.get(self) {
+    fn access(&self, vm: &mut Vm, f: Handler) -> TypResult<()> {
+        match vm.scopes.get(self) {
             Some(slot) => match slot.try_write() {
                 Ok(mut guard) => f(&mut guard),
                 Err(_) => bail!(self.span(), "cannot mutate a constant"),
@@ -860,10 +787,10 @@ impl Access for Ident {
 }
 
 impl Access for CallExpr {
-    fn access(&self, ctx: &mut EvalContext, f: Handler) -> TypResult<()> {
-        let args = self.args().eval(ctx)?;
+    fn access(&self, vm: &mut Vm, f: Handler) -> TypResult<()> {
+        let args = self.args().eval(vm)?;
         self.callee().access(
-            ctx,
+            vm,
             Box::new(|value| match value {
                 Value::Array(array) => {
                     f(array.get_mut(args.into_index()?).at(self.span())?)
diff --git a/src/eval/scope.rs b/src/eval/scope.rs
index ed4ff70d..0df4c4df 100644
--- a/src/eval/scope.rs
+++ b/src/eval/scope.rs
@@ -4,7 +4,7 @@ use std::hash::{Hash, Hasher};
 use std::iter;
 use std::sync::{Arc, RwLock};
 
-use super::{Args, Class, Construct, EvalContext, Func, Set, Value};
+use super::{Args, Class, Construct, Func, Set, Value, Vm};
 use crate::diag::TypResult;
 use crate::util::EcoString;
 
@@ -40,21 +40,6 @@ impl<'a> Scopes<'a> {
         self.top = self.scopes.pop().expect("no pushed scope");
     }
 
-    /// Define a constant variable with a value in the active scope.
-    pub fn def_const(&mut self, var: impl Into<EcoString>, value: impl Into<Value>) {
-        self.top.def_const(var, value);
-    }
-
-    /// Define a mutable variable with a value in the active scope.
-    pub fn def_mut(&mut self, var: impl Into<EcoString>, value: impl Into<Value>) {
-        self.top.def_mut(var, value);
-    }
-
-    /// Define a variable with a slot in the active scope.
-    pub fn def_slot(&mut self, var: impl Into<EcoString>, slot: Slot) {
-        self.top.def_slot(var, slot);
-    }
-
     /// Look up the slot of a variable.
     pub fn get(&self, var: &str) -> Option<&Slot> {
         iter::once(&self.top)
@@ -101,7 +86,7 @@ impl Scope {
     pub fn def_func(
         &mut self,
         name: &'static str,
-        func: fn(&mut EvalContext, &mut Args) -> TypResult<Value>,
+        func: fn(&mut Vm, &mut Args) -> TypResult<Value>,
     ) {
         self.def_const(name, Func::native(name, func));
     }
diff --git a/src/eval/template.rs b/src/eval/template.rs
index f953287d..2cd6797a 100644
--- a/src/eval/template.rs
+++ b/src/eval/template.rs
@@ -17,7 +17,6 @@ use crate::library::{
     TextNode, UNDERLINE,
 };
 use crate::util::EcoString;
-use crate::Context;
 
 /// Composable representation of styled content.
 ///
@@ -166,19 +165,19 @@ impl Template {
     }
 
     /// Layout this template into a collection of pages.
-    pub fn layout(&self, ctx: &mut Context) -> Vec<Arc<Frame>> {
+    pub fn layout(&self, vm: &mut Vm) -> Vec<Arc<Frame>> {
         let style_arena = Arena::new();
         let template_arena = Arena::new();
-        let (mut ctx, styles) = LayoutContext::new(ctx);
 
         let mut builder = Builder::new(&style_arena, &template_arena, true);
-        builder.process(self, styles);
-        builder.finish_page(true, false, styles);
+        let chain = StyleChain::new(vm.styles);
+        builder.process(self, chain);
+        builder.finish_page(true, false, chain);
 
         let (pages, shared) = builder.pages.unwrap().finish();
         pages
             .iter()
-            .flat_map(|(page, map)| page.layout(&mut ctx, map.chain(&shared)))
+            .flat_map(|(page, map)| page.layout(vm, map.chain(&shared)))
             .collect()
     }
 }
@@ -267,7 +266,7 @@ impl Sum for Template {
 impl Layout for Template {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -279,7 +278,7 @@ impl Layout for Template {
         builder.finish_par(styles);
 
         let (flow, shared) = builder.flow.finish();
-        FlowNode(flow).layout(ctx, regions, shared)
+        FlowNode(flow).layout(vm, regions, shared)
     }
 
     fn pack(self) -> LayoutNode {
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index c334433e..d47e37bb 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -16,13 +16,11 @@ use std::hash::{Hash, Hasher};
 use std::sync::Arc;
 
 use crate::eval::StyleChain;
-use crate::font::FontStore;
 use crate::frame::{Element, Frame, Geometry, Shape, Stroke};
 use crate::geom::{Align, Linear, Paint, Point, Sides, Size, Spec, Transform};
-use crate::image::ImageStore;
 use crate::library::{AlignNode, PadNode, TransformNode, MOVE};
 use crate::util::Prehashed;
-use crate::Context;
+use crate::Vm;
 
 /// A node that can be layouted into a sequence of regions.
 ///
@@ -32,7 +30,7 @@ pub trait Layout {
     /// Layout the node into the given regions, producing constrained frames.
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>>;
@@ -46,35 +44,6 @@ pub trait Layout {
     }
 }
 
-/// The context for layouting.
-pub struct LayoutContext<'a> {
-    /// Stores parsed font faces.
-    pub fonts: &'a mut FontStore,
-    /// Stores decoded images.
-    pub images: &'a mut ImageStore,
-    /// Caches layouting artifacts.
-    #[cfg(feature = "layout-cache")]
-    pub layout_cache: &'a mut LayoutCache,
-    /// How deeply nested the current layout tree position is.
-    #[cfg(feature = "layout-cache")]
-    level: usize,
-}
-
-impl<'a> LayoutContext<'a> {
-    /// Create a new layout context and style chain.
-    pub fn new(ctx: &'a mut Context) -> (Self, StyleChain<'a>) {
-        let this = Self {
-            fonts: &mut ctx.fonts,
-            images: &mut ctx.images,
-            #[cfg(feature = "layout-cache")]
-            layout_cache: &mut ctx.layout_cache,
-            #[cfg(feature = "layout-cache")]
-            level: 0,
-        };
-        (this, StyleChain::new(&ctx.styles))
-    }
-}
-
 /// A type-erased layouting node with a precomputed hash.
 #[derive(Clone, Hash)]
 pub struct LayoutNode(Arc<Prehashed<dyn Bounds>>);
@@ -165,7 +134,7 @@ impl Layout for LayoutNode {
     #[track_caller]
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -185,14 +154,14 @@ impl Layout for LayoutNode {
         // This is not written with `unwrap_or_else`, because then the
         // #[track_caller] annotation doesn't work.
         #[cfg(feature = "layout-cache")]
-        if let Some(frames) = ctx.layout_cache.get(hash, regions) {
+        if let Some(frames) = vm.layout_cache.get(hash, regions) {
             frames
         } else {
-            ctx.level += 1;
-            let frames = self.0.layout(ctx, regions, styles);
-            ctx.level -= 1;
+            vm.level += 1;
+            let frames = self.0.layout(vm, regions, styles);
+            vm.level -= 1;
 
-            let entry = FramesEntry::new(frames.clone(), ctx.level);
+            let entry = FramesEntry::new(frames.clone(), vm.level);
 
             #[cfg(debug_assertions)]
             if !entry.check(regions) {
@@ -205,7 +174,7 @@ impl Layout for LayoutNode {
                 panic!("constraints did not match regions they were created for");
             }
 
-            ctx.layout_cache.insert(hash, entry);
+            vm.layout_cache.insert(hash, entry);
             frames
         }
     }
@@ -276,7 +245,7 @@ struct EmptyNode;
 impl Layout for EmptyNode {
     fn layout(
         &self,
-        _: &mut LayoutContext,
+        _: &mut Vm,
         regions: &Regions,
         _: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -299,7 +268,7 @@ struct SizedNode {
 impl Layout for SizedNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -323,7 +292,7 @@ impl Layout for SizedNode {
             Regions::one(size, base, expand)
         };
 
-        let mut frames = self.child.layout(ctx, &pod, styles);
+        let mut frames = self.child.layout(vm, &pod, styles);
         let Constrained { item: frame, cts } = &mut frames[0];
 
         // Ensure frame size matches regions size if expansion is on.
@@ -353,11 +322,11 @@ struct FillNode {
 impl Layout for FillNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
-        let mut frames = self.child.layout(ctx, regions, styles);
+        let mut frames = self.child.layout(vm, regions, styles);
         for Constrained { item: frame, .. } in &mut frames {
             let shape = Shape::filled(Geometry::Rect(frame.size), self.fill);
             Arc::make_mut(frame).prepend(Point::zero(), Element::Shape(shape));
@@ -378,11 +347,11 @@ struct StrokeNode {
 impl Layout for StrokeNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
-        let mut frames = self.child.layout(ctx, regions, styles);
+        let mut frames = self.child.layout(vm, regions, styles);
         for Constrained { item: frame, .. } in &mut frames {
             let shape = Shape::stroked(Geometry::Rect(frame.size), self.stroke);
             Arc::make_mut(frame).prepend(Point::zero(), Element::Shape(shape));
diff --git a/src/lib.rs b/src/lib.rs
index 99958aac..d4a8fba5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,7 +22,7 @@
 //! [parsed]: parse::parse
 //! [green tree]: syntax::GreenNode
 //! [AST]: syntax::ast
-//! [evaluate]: Context::evaluate
+//! [evaluate]: Vm::evaluate
 //! [module]: eval::Module
 //! [template]: eval::Template
 //! [layouted]: eval::Template::layout
@@ -51,10 +51,12 @@ pub mod parse;
 pub mod source;
 pub mod syntax;
 
+use std::collections::HashMap;
+use std::path::PathBuf;
 use std::sync::Arc;
 
 use crate::diag::TypResult;
-use crate::eval::{Eval, EvalContext, Module, Scope, StyleMap};
+use crate::eval::{Eval, Module, Scope, Scopes, StyleMap};
 use crate::export::RenderCache;
 use crate::font::FontStore;
 use crate::frame::Frame;
@@ -106,27 +108,13 @@ impl Context {
         &self.styles
     }
 
-    /// Evaluate a source file and return the resulting module.
-    ///
-    /// Returns either a module containing a scope with top-level bindings and a
-    /// layoutable template or diagnostics in the form of a vector of error
-    /// message with file and span information.
-    pub fn evaluate(&mut self, id: SourceId) -> TypResult<Module> {
-        let markup = self.sources.get(id).ast()?;
-        let mut ctx = EvalContext::new(self, id);
-        let template = markup.eval(&mut ctx)?;
-        Ok(Module { scope: ctx.scopes.top, template })
-    }
-
     /// Typeset a source file into a collection of layouted frames.
     ///
     /// Returns either a vector of frames representing individual pages or
     /// diagnostics in the form of a vector of error message with file and span
     /// information.
     pub fn typeset(&mut self, id: SourceId) -> TypResult<Vec<Arc<Frame>>> {
-        let module = self.evaluate(id)?;
-        let frames = module.template.layout(self);
-        Ok(frames)
+        Vm::new(self).typeset(id)
     }
 
     /// Garbage-collect caches.
@@ -208,3 +196,107 @@ impl Default for ContextBuilder {
         }
     }
 }
+
+/// A virtual machine for a single typesetting process.
+pub struct Vm<'a> {
+    /// The loader the context was created with.
+    pub loader: &'a dyn Loader,
+    /// Stores loaded source files.
+    pub sources: &'a mut SourceStore,
+    /// Stores parsed font faces.
+    pub fonts: &'a mut FontStore,
+    /// Stores decoded images.
+    pub images: &'a mut ImageStore,
+    /// Caches layouting artifacts.
+    #[cfg(feature = "layout-cache")]
+    pub layout_cache: &'a mut LayoutCache,
+    /// The default styles.
+    pub styles: &'a StyleMap,
+    /// The stack of imported files that led to evaluation of the current file.
+    pub route: Vec<SourceId>,
+    /// Caches imported modules.
+    pub modules: HashMap<SourceId, Module>,
+    /// The active scopes.
+    pub scopes: Scopes<'a>,
+    /// How deeply nested the current layout tree position is.
+    #[cfg(feature = "layout-cache")]
+    pub level: usize,
+}
+
+impl<'a> Vm<'a> {
+    /// Create a new virtual machine.
+    pub fn new(ctx: &'a mut Context) -> Self {
+        Self {
+            loader: ctx.loader.as_ref(),
+            sources: &mut ctx.sources,
+            fonts: &mut ctx.fonts,
+            images: &mut ctx.images,
+            layout_cache: &mut ctx.layout_cache,
+            styles: &ctx.styles,
+            route: vec![],
+            modules: HashMap::new(),
+            scopes: Scopes::new(Some(&ctx.std)),
+            level: 0,
+        }
+    }
+
+    /// Evaluate a source file and return the resulting module.
+    ///
+    /// Returns either a module containing a scope with top-level bindings and a
+    /// layoutable template or diagnostics in the form of a vector of error
+    /// message with file and span information.
+    pub fn evaluate(&mut self, id: SourceId) -> TypResult<Module> {
+        // Prevent cyclic evaluation.
+        assert!(!self.route.contains(&id));
+
+        // Check whether the module was already loaded.
+        if let Some(module) = self.modules.get(&id) {
+            return Ok(module.clone());
+        }
+
+        // Parse the file.
+        let source = self.sources.get(id);
+        let ast = source.ast()?;
+
+        // Prepare the new context.
+        let fresh = Scopes::new(self.scopes.base);
+        let prev = std::mem::replace(&mut self.scopes, fresh);
+        self.route.push(id);
+
+        // Evaluate the module.
+        let template = ast.eval(self)?;
+
+        // Restore the old context.
+        let scope = std::mem::replace(&mut self.scopes, prev).top;
+        self.route.pop().unwrap();
+
+        // Save the evaluated module.
+        let module = Module { scope, template };
+        self.modules.insert(id, module.clone());
+
+        Ok(module)
+    }
+
+    /// Typeset a source file into a collection of layouted frames.
+    ///
+    /// Returns either a vector of frames representing individual pages or
+    /// diagnostics in the form of a vector of error message with file and span
+    /// information.
+    pub fn typeset(&mut self, id: SourceId) -> TypResult<Vec<Arc<Frame>>> {
+        let module = self.evaluate(id)?;
+        let frames = module.template.layout(self);
+        Ok(frames)
+    }
+
+    /// Resolve a user-entered path (relative to the source file) to be
+    /// relative to the compilation environment's root.
+    pub fn resolve(&self, path: &str) -> PathBuf {
+        if let Some(&id) = self.route.last() {
+            if let Some(dir) = self.sources.get(id).path().parent() {
+                return dir.join(path);
+            }
+        }
+
+        path.into()
+    }
+}
diff --git a/src/library/align.rs b/src/library/align.rs
index 1fb91138..5b50937e 100644
--- a/src/library/align.rs
+++ b/src/library/align.rs
@@ -14,7 +14,7 @@ pub struct AlignNode {
 
 #[class]
 impl AlignNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let aligns: Spec<_> = args.find()?.unwrap_or_default();
         let body: LayoutNode = args.expect("body")?;
         Ok(Template::block(body.aligned(aligns)))
@@ -24,7 +24,7 @@ impl AlignNode {
 impl Layout for AlignNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -39,7 +39,7 @@ impl Layout for AlignNode {
         }
 
         // Layout the child.
-        let mut frames = self.child.layout(ctx, &pod, passed.chain(&styles));
+        let mut frames = self.child.layout(vm, &pod, passed.chain(&styles));
 
         for ((current, base), Constrained { item: frame, cts }) in
             regions.iter().zip(&mut frames)
diff --git a/src/library/columns.rs b/src/library/columns.rs
index 98989c5a..61da6177 100644
--- a/src/library/columns.rs
+++ b/src/library/columns.rs
@@ -18,7 +18,7 @@ impl ColumnsNode {
     /// The size of the gutter space between each column.
     pub const GUTTER: Linear = Relative::new(0.04).into();
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::block(Self {
             columns: args.expect("column count")?,
             child: args.expect("body")?,
@@ -29,14 +29,14 @@ impl ColumnsNode {
 impl Layout for ColumnsNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
         // Separating the infinite space into infinite columns does not make
         // much sense.
         if regions.current.x.is_infinite() {
-            return self.child.layout(ctx, regions, styles);
+            return self.child.layout(vm, regions, styles);
         }
 
         // Determine the width of the gutter and each column.
@@ -59,7 +59,7 @@ impl Layout for ColumnsNode {
         };
 
         // Layout the children.
-        let mut frames = self.child.layout(ctx, &pod, styles).into_iter();
+        let mut frames = self.child.layout(vm, &pod, styles).into_iter();
 
         let dir = styles.get(ParNode::DIR);
         let total_regions = (frames.len() as f32 / columns as f32).ceil() as usize;
@@ -111,7 +111,7 @@ pub struct ColbreakNode;
 
 #[class]
 impl ColbreakNode {
-    fn construct(_: &mut EvalContext, _: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, _: &mut Args) -> TypResult<Template> {
         Ok(Template::Colbreak)
     }
 }
diff --git a/src/library/container.rs b/src/library/container.rs
index 382be262..fafa7103 100644
--- a/src/library/container.rs
+++ b/src/library/container.rs
@@ -7,7 +7,7 @@ pub struct BoxNode;
 
 #[class]
 impl BoxNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let width = args.named("width")?;
         let height = args.named("height")?;
         let body: LayoutNode = args.find()?.unwrap_or_default();
@@ -20,7 +20,7 @@ pub struct BlockNode;
 
 #[class]
 impl BlockNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::Block(args.find()?.unwrap_or_default()))
     }
 }
diff --git a/src/library/deco.rs b/src/library/deco.rs
index 5e438d54..92fcf09f 100644
--- a/src/library/deco.rs
+++ b/src/library/deco.rs
@@ -26,7 +26,7 @@ impl<const L: DecoLine> DecoNode<L> {
     /// with the glyphs. Does not apply to strikethrough.
     pub const EVADE: bool = true;
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::show(Self(args.expect::<Template>("body")?)))
     }
 }
diff --git a/src/library/flow.rs b/src/library/flow.rs
index ca554033..95469b65 100644
--- a/src/library/flow.rs
+++ b/src/library/flow.rs
@@ -28,7 +28,7 @@ pub enum FlowChild {
 impl Layout for FlowNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -56,7 +56,7 @@ impl Layout for FlowNode {
                     layouter.layout_spacing(*kind);
                 }
                 FlowChild::Node(ref node) => {
-                    layouter.layout_node(ctx, node, styles);
+                    layouter.layout_node(vm, node, styles);
                 }
             }
         }
@@ -161,12 +161,7 @@ impl FlowLayouter {
     }
 
     /// Layout a node.
-    pub fn layout_node(
-        &mut self,
-        ctx: &mut LayoutContext,
-        node: &LayoutNode,
-        styles: StyleChain,
-    ) {
+    pub fn layout_node(&mut self, vm: &mut Vm, node: &LayoutNode, styles: StyleChain) {
         // Don't even try layouting into a full region.
         if self.regions.is_full() {
             self.finish_region();
@@ -176,7 +171,7 @@ impl FlowLayouter {
         // aligned later.
         if let Some(placed) = node.downcast::<PlaceNode>() {
             if placed.out_of_flow() {
-                let frame = node.layout(ctx, &self.regions, styles).remove(0);
+                let frame = node.layout(vm, &self.regions, styles).remove(0);
                 self.items.push(FlowItem::Placed(frame.item));
                 return;
             }
@@ -193,7 +188,7 @@ impl FlowLayouter {
                 .unwrap_or(Align::Top),
         );
 
-        let frames = node.layout(ctx, &self.regions, styles);
+        let frames = node.layout(vm, &self.regions, styles);
         let len = frames.len();
         for (i, frame) in frames.into_iter().enumerate() {
             // Grow our size, shrink the region and save the frame for later.
diff --git a/src/library/grid.rs b/src/library/grid.rs
index c9904a5f..78ac375f 100644
--- a/src/library/grid.rs
+++ b/src/library/grid.rs
@@ -15,7 +15,7 @@ pub struct GridNode {
 
 #[class]
 impl GridNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let columns = args.named("columns")?.unwrap_or_default();
         let rows = args.named("rows")?.unwrap_or_default();
         let base_gutter: Vec<TrackSizing> = args.named("gutter")?.unwrap_or_default();
@@ -35,7 +35,7 @@ impl GridNode {
 impl Layout for GridNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -49,7 +49,7 @@ impl Layout for GridNode {
         );
 
         // Measure the columsna nd layout the grid row-by-row.
-        layouter.layout(ctx)
+        layouter.layout(vm)
     }
 }
 
@@ -205,19 +205,19 @@ impl<'a> GridLayouter<'a> {
     }
 
     /// Determines the columns sizes and then layouts the grid row-by-row.
-    pub fn layout(mut self, ctx: &mut LayoutContext) -> Vec<Constrained<Arc<Frame>>> {
-        self.measure_columns(ctx);
+    pub fn layout(mut self, vm: &mut Vm) -> Vec<Constrained<Arc<Frame>>> {
+        self.measure_columns(vm);
 
         for y in 0 .. self.rows.len() {
             // Skip to next region if current one is full, but only for content
             // rows, not for gutter rows.
             if y % 2 == 0 && self.regions.is_full() {
-                self.finish_region(ctx);
+                self.finish_region(vm);
             }
 
             match self.rows[y] {
-                TrackSizing::Auto => self.layout_auto_row(ctx, y),
-                TrackSizing::Linear(v) => self.layout_linear_row(ctx, v, y),
+                TrackSizing::Auto => self.layout_auto_row(vm, y),
+                TrackSizing::Linear(v) => self.layout_linear_row(vm, v, y),
                 TrackSizing::Fractional(v) => {
                     self.cts.exact.y = Some(self.full);
                     self.lrows.push(Row::Fr(v, y));
@@ -226,12 +226,12 @@ impl<'a> GridLayouter<'a> {
             }
         }
 
-        self.finish_region(ctx);
+        self.finish_region(vm);
         self.finished
     }
 
     /// Determine all column sizes.
-    fn measure_columns(&mut self, ctx: &mut LayoutContext) {
+    fn measure_columns(&mut self, vm: &mut Vm) {
         enum Case {
             /// The column sizing is only determined by specified linear sizes.
             PurelyLinear,
@@ -277,7 +277,7 @@ impl<'a> GridLayouter<'a> {
         let available = self.regions.current.x - linear;
         if available >= Length::zero() {
             // Determine size of auto columns.
-            let (auto, count) = self.measure_auto_columns(ctx, available);
+            let (auto, count) = self.measure_auto_columns(vm, available);
 
             // If there is remaining space, distribute it to fractional columns,
             // otherwise shrink auto columns.
@@ -313,7 +313,7 @@ impl<'a> GridLayouter<'a> {
     /// Measure the size that is available to auto columns.
     fn measure_auto_columns(
         &mut self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         available: Length,
     ) -> (Length, usize) {
         let mut auto = Length::zero();
@@ -340,7 +340,7 @@ impl<'a> GridLayouter<'a> {
                         pod.base.y = v.resolve(self.regions.base.y);
                     }
 
-                    let frame = node.layout(ctx, &pod, self.styles).remove(0).item;
+                    let frame = node.layout(vm, &pod, self.styles).remove(0).item;
                     resolved.set_max(frame.size.x);
                 }
             }
@@ -394,7 +394,7 @@ impl<'a> GridLayouter<'a> {
 
     /// Layout a row with automatic height. Such a row may break across multiple
     /// regions.
-    fn layout_auto_row(&mut self, ctx: &mut LayoutContext, y: usize) {
+    fn layout_auto_row(&mut self, vm: &mut Vm, y: usize) {
         let mut resolved: Vec<Length> = vec![];
 
         // Determine the size for each region of the row.
@@ -409,7 +409,7 @@ impl<'a> GridLayouter<'a> {
                 }
 
                 let mut sizes = node
-                    .layout(ctx, &pod, self.styles)
+                    .layout(vm, &pod, self.styles)
                     .into_iter()
                     .map(|frame| frame.item.size.y);
 
@@ -432,7 +432,7 @@ impl<'a> GridLayouter<'a> {
 
         // Layout into a single region.
         if let &[first] = resolved.as_slice() {
-            let frame = self.layout_single_row(ctx, first, y);
+            let frame = self.layout_single_row(vm, first, y);
             self.push_row(frame);
             return;
         }
@@ -449,28 +449,28 @@ impl<'a> GridLayouter<'a> {
         }
 
         // Layout into multiple regions.
-        let frames = self.layout_multi_row(ctx, &resolved, y);
+        let frames = self.layout_multi_row(vm, &resolved, y);
         let len = frames.len();
         for (i, frame) in frames.into_iter().enumerate() {
             self.push_row(frame);
             if i + 1 < len {
                 self.cts.exact.y = Some(self.full);
-                self.finish_region(ctx);
+                self.finish_region(vm);
             }
         }
     }
 
     /// Layout a row with linear height. Such a row cannot break across multiple
     /// regions, but it may force a region break.
-    fn layout_linear_row(&mut self, ctx: &mut LayoutContext, v: Linear, y: usize) {
+    fn layout_linear_row(&mut self, vm: &mut Vm, v: Linear, y: usize) {
         let resolved = v.resolve(self.regions.base.y);
-        let frame = self.layout_single_row(ctx, resolved, y);
+        let frame = self.layout_single_row(vm, resolved, y);
 
         // Skip to fitting region.
         let height = frame.size.y;
         while !self.regions.current.y.fits(height) && !self.regions.in_last() {
             self.cts.max.y = Some(self.used.y + height);
-            self.finish_region(ctx);
+            self.finish_region(vm);
 
             // Don't skip multiple regions for gutter and don't push a row.
             if y % 2 == 1 {
@@ -484,7 +484,7 @@ impl<'a> GridLayouter<'a> {
     /// Layout a row with fixed height and return its frame.
     fn layout_single_row(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         height: Length,
         y: usize,
     ) -> Frame {
@@ -502,7 +502,7 @@ impl<'a> GridLayouter<'a> {
                     .select(self.regions.base, size);
 
                 let pod = Regions::one(size, base, Spec::splat(true));
-                let frame = node.layout(ctx, &pod, self.styles).remove(0);
+                let frame = node.layout(vm, &pod, self.styles).remove(0);
                 output.push_frame(pos, frame.item);
             }
 
@@ -515,7 +515,7 @@ impl<'a> GridLayouter<'a> {
     /// Layout a row spanning multiple regions.
     fn layout_multi_row(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         heights: &[Length],
         y: usize,
     ) -> Vec<Frame> {
@@ -542,7 +542,7 @@ impl<'a> GridLayouter<'a> {
                 }
 
                 // Push the layouted frames into the individual output frames.
-                let frames = node.layout(ctx, &pod, self.styles);
+                let frames = node.layout(vm, &pod, self.styles);
                 for (output, frame) in outputs.iter_mut().zip(frames) {
                     output.push_frame(pos, frame.item);
                 }
@@ -562,7 +562,7 @@ impl<'a> GridLayouter<'a> {
     }
 
     /// Finish rows for one region.
-    fn finish_region(&mut self, ctx: &mut LayoutContext) {
+    fn finish_region(&mut self, vm: &mut Vm) {
         // Determine the size of the grid in this region, expanding fully if
         // there are fr rows.
         let mut size = self.used;
@@ -584,7 +584,7 @@ impl<'a> GridLayouter<'a> {
                 Row::Fr(v, y) => {
                     let remaining = self.full - self.used.y;
                     let height = v.resolve(self.fr, remaining);
-                    self.layout_single_row(ctx, height, y)
+                    self.layout_single_row(vm, height, y)
                 }
             };
 
diff --git a/src/library/heading.rs b/src/library/heading.rs
index 00a48021..2123116b 100644
--- a/src/library/heading.rs
+++ b/src/library/heading.rs
@@ -34,7 +34,7 @@ impl HeadingNode {
     /// The extra padding below the heading.
     pub const BELOW: Length = Length::zero();
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::show(Self {
             body: args.expect("body")?,
             level: args.named("level")?.unwrap_or(1),
diff --git a/src/library/hide.rs b/src/library/hide.rs
index 72d8e52b..230300d2 100644
--- a/src/library/hide.rs
+++ b/src/library/hide.rs
@@ -8,7 +8,7 @@ pub struct HideNode(pub LayoutNode);
 
 #[class]
 impl HideNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::inline(Self(args.expect("body")?)))
     }
 }
@@ -16,11 +16,11 @@ impl HideNode {
 impl Layout for HideNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
-        let mut frames = self.0.layout(ctx, regions, styles);
+        let mut frames = self.0.layout(vm, regions, styles);
 
         // Clear the frames.
         for Constrained { item: frame, .. } in &mut frames {
diff --git a/src/library/image.rs b/src/library/image.rs
index 59e30364..5527fbdc 100644
--- a/src/library/image.rs
+++ b/src/library/image.rs
@@ -14,10 +14,10 @@ impl ImageNode {
     /// How the image should adjust itself to a given area.
     pub const FIT: ImageFit = ImageFit::Cover;
 
-    fn construct(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(vm: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let path = args.expect::<Spanned<EcoString>>("path to image file")?;
-        let full = ctx.make_path(&path.v);
-        let id = ctx.images.load(&full).map_err(|err| {
+        let full = vm.resolve(&path.v);
+        let id = vm.images.load(&full).map_err(|err| {
             Error::boxed(path.span, match err.kind() {
                 std::io::ErrorKind::NotFound => "file not found".into(),
                 _ => format!("failed to load image ({})", err),
@@ -36,11 +36,11 @@ impl ImageNode {
 impl Layout for ImageNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
-        let img = ctx.images.get(self.0);
+        let img = vm.images.get(self.0);
         let pxw = img.width() as f64;
         let pxh = img.height() as f64;
         let px_ratio = pxw / pxh;
diff --git a/src/library/link.rs b/src/library/link.rs
index 42c630f6..58c7e550 100644
--- a/src/library/link.rs
+++ b/src/library/link.rs
@@ -21,7 +21,7 @@ impl LinkNode {
     /// Whether to underline link.
     pub const UNDERLINE: bool = true;
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let url = args.expect::<EcoString>("url")?;
         let body = args.find()?.unwrap_or_else(|| {
             let mut text = url.as_str();
diff --git a/src/library/list.rs b/src/library/list.rs
index e07177f4..7f76a178 100644
--- a/src/library/list.rs
+++ b/src/library/list.rs
@@ -19,7 +19,7 @@ impl<const L: Labelling> ListNode<L> {
     /// The space between the label and the body of each item.
     pub const BODY_INDENT: Linear = Relative::new(0.5).into();
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(args
             .all()?
             .into_iter()
diff --git a/src/library/math.rs b/src/library/math.rs
index c75cdea8..29367cd5 100644
--- a/src/library/math.rs
+++ b/src/library/math.rs
@@ -13,7 +13,7 @@ pub struct MathNode {
 
 #[class]
 impl MathNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::show(Self {
             formula: args.expect("formula")?,
             display: args.named("display")?.unwrap_or(false),
diff --git a/src/library/mod.rs b/src/library/mod.rs
index db173daf..d90c96da 100644
--- a/src/library/mod.rs
+++ b/src/library/mod.rs
@@ -64,16 +64,17 @@ pub mod prelude {
 
     pub use crate::diag::{At, TypResult};
     pub use crate::eval::{
-        Args, Construct, EvalContext, Merge, Property, Scope, Set, Show, ShowNode, Smart,
-        StyleChain, StyleMap, StyleVec, Template, Value,
+        Args, Construct, Merge, Property, Scope, Set, Show, ShowNode, Smart, StyleChain,
+        StyleMap, StyleVec, Template, Value,
     };
     pub use crate::frame::*;
     pub use crate::geom::*;
     pub use crate::layout::{
-        Constrain, Constrained, Constraints, Layout, LayoutContext, LayoutNode, Regions,
+        Constrain, Constrained, Constraints, Layout, LayoutNode, Regions,
     };
     pub use crate::syntax::{Span, Spanned};
     pub use crate::util::{EcoString, OptionExt};
+    pub use crate::Vm;
 }
 
 use prelude::*;
diff --git a/src/library/pad.rs b/src/library/pad.rs
index 684e1172..84e83939 100644
--- a/src/library/pad.rs
+++ b/src/library/pad.rs
@@ -13,7 +13,7 @@ pub struct PadNode {
 
 #[class]
 impl PadNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let all = args.find()?;
         let left = args.named("left")?;
         let top = args.named("top")?;
@@ -34,13 +34,13 @@ impl PadNode {
 impl Layout for PadNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
         // Layout child into padded regions.
         let pod = regions.map(|size| shrink(size, self.padding));
-        let mut frames = self.child.layout(ctx, &pod, styles);
+        let mut frames = self.child.layout(vm, &pod, styles);
 
         for ((current, base), Constrained { item: frame, cts }) in
             regions.iter().zip(&mut frames)
diff --git a/src/library/page.rs b/src/library/page.rs
index 7f0f7332..155f60dd 100644
--- a/src/library/page.rs
+++ b/src/library/page.rs
@@ -31,7 +31,7 @@ impl PageNode {
     /// How many columns the page has.
     pub const COLUMNS: NonZeroUsize = NonZeroUsize::new(1).unwrap();
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::Page(Self(args.expect("body")?)))
     }
 
@@ -60,7 +60,7 @@ impl PageNode {
 
 impl PageNode {
     /// Layout the page run into a sequence of frames, one per page.
-    pub fn layout(&self, ctx: &mut LayoutContext, styles: StyleChain) -> Vec<Arc<Frame>> {
+    pub fn layout(&self, vm: &mut Vm, styles: StyleChain) -> Vec<Arc<Frame>> {
         // When one of the lengths is infinite the page fits its content along
         // that axis.
         let width = styles.get(Self::WIDTH).unwrap_or(Length::inf());
@@ -104,7 +104,7 @@ impl PageNode {
         let expand = size.map(Length::is_finite);
         let regions = Regions::repeat(size, size, expand);
         child
-            .layout(ctx, &regions, styles)
+            .layout(vm, &regions, styles)
             .into_iter()
             .map(|c| c.item)
             .collect()
@@ -124,7 +124,7 @@ pub struct PagebreakNode;
 
 #[class]
 impl PagebreakNode {
-    fn construct(_: &mut EvalContext, _: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, _: &mut Args) -> TypResult<Template> {
         Ok(Template::Pagebreak)
     }
 }
diff --git a/src/library/par.rs b/src/library/par.rs
index 2a4b4d08..02633612 100644
--- a/src/library/par.rs
+++ b/src/library/par.rs
@@ -36,7 +36,7 @@ impl ParNode {
     /// The extra spacing between paragraphs (dependent on scaled font size).
     pub const SPACING: Linear = Relative::new(0.55).into();
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         // The paragraph constructor is special: It doesn't create a paragraph
         // since that happens automatically through markup. Instead, it just
         // lifts the passed body to the block level so that it won't merge with
@@ -82,7 +82,7 @@ impl ParNode {
 impl Layout for ParNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -95,10 +95,10 @@ impl Layout for ParNode {
 
         // Prepare paragraph layout by building a representation on which we can
         // do line breaking without layouting each and every line from scratch.
-        let layouter = ParLayouter::new(self, ctx, regions, &styles, bidi);
+        let layouter = ParLayouter::new(self, vm, regions, &styles, bidi);
 
         // Find suitable linebreaks.
-        layouter.layout(ctx, regions.clone())
+        layouter.layout(vm, regions.clone())
     }
 }
 
@@ -167,7 +167,7 @@ pub struct ParbreakNode;
 
 #[class]
 impl ParbreakNode {
-    fn construct(_: &mut EvalContext, _: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, _: &mut Args) -> TypResult<Template> {
         Ok(Template::Parbreak)
     }
 }
@@ -177,7 +177,7 @@ pub struct LinebreakNode;
 
 #[class]
 impl LinebreakNode {
-    fn construct(_: &mut EvalContext, _: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, _: &mut Args) -> TypResult<Template> {
         Ok(Template::Linebreak)
     }
 }
@@ -216,7 +216,7 @@ impl<'a> ParLayouter<'a> {
     /// Prepare initial shaped text and layouted children.
     fn new(
         par: &'a ParNode,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: &'a StyleChain<'a>,
         bidi: BidiInfo<'a>,
@@ -236,7 +236,7 @@ impl<'a> ParLayouter<'a> {
                         cursor += count;
                         let subrange = start .. cursor;
                         let text = &bidi.text[subrange.clone()];
-                        let shaped = shape(ctx.fonts, text, styles, level.dir());
+                        let shaped = shape(vm.fonts, text, styles, level.dir());
                         items.push(ParItem::Text(shaped));
                         ranges.push(subrange);
                     }
@@ -255,7 +255,7 @@ impl<'a> ParLayouter<'a> {
                 ParChild::Node(node) => {
                     let size = Size::new(regions.current.x, regions.base.y);
                     let pod = Regions::one(size, regions.base, Spec::splat(false));
-                    let frame = node.layout(ctx, &pod, styles).remove(0);
+                    let frame = node.layout(vm, &pod, styles).remove(0);
                     items.push(ParItem::Frame(Arc::take(frame.item)));
                     ranges.push(range);
                 }
@@ -270,11 +270,7 @@ impl<'a> ParLayouter<'a> {
     }
 
     /// Find first-fit line breaks and build the paragraph.
-    fn layout(
-        self,
-        ctx: &mut LayoutContext,
-        regions: Regions,
-    ) -> Vec<Constrained<Arc<Frame>>> {
+    fn layout(self, vm: &mut Vm, regions: Regions) -> Vec<Constrained<Arc<Frame>>> {
         let mut stack = LineStack::new(self.leading, regions);
 
         // The current line attempt.
@@ -288,7 +284,7 @@ impl<'a> ParLayouter<'a> {
         // TODO: Provide line break opportunities on alignment changes.
         for (end, mandatory) in LineBreakIterator::new(self.bidi.text) {
             // Compute the line and its size.
-            let mut line = LineLayout::new(ctx, &self, start .. end);
+            let mut line = LineLayout::new(vm, &self, start .. end);
 
             // If the line doesn't fit anymore, we push the last fitting attempt
             // into the stack and rebuild the line from its end. The resulting
@@ -318,7 +314,7 @@ impl<'a> ParLayouter<'a> {
                         stack.push(last_line);
                         stack.cts.min.y = Some(stack.size.y);
                         start = last_end;
-                        line = LineLayout::new(ctx, &self, start .. end);
+                        line = LineLayout::new(vm, &self, start .. end);
                     }
                 }
             }
@@ -335,7 +331,7 @@ impl<'a> ParLayouter<'a> {
                 // below.
                 let too_large = stack.size.y + self.leading + line.size.y;
                 stack.cts.max.y.set_min(too_large);
-                stack.finish_region(ctx);
+                stack.finish_region(vm);
             }
 
             // If the line does not fit horizontally or we have a mandatory
@@ -350,7 +346,7 @@ impl<'a> ParLayouter<'a> {
                 // If there is a trailing line break at the end of the
                 // paragraph, we want to force an empty line.
                 if mandatory && end == self.bidi.text.len() {
-                    let line = LineLayout::new(ctx, &self, end .. end);
+                    let line = LineLayout::new(vm, &self, end .. end);
                     if stack.regions.current.y.fits(line.size.y) {
                         stack.push(line);
                     }
@@ -370,7 +366,7 @@ impl<'a> ParLayouter<'a> {
             stack.cts.min.y = Some(stack.size.y);
         }
 
-        stack.finish(ctx)
+        stack.finish(vm)
     }
 
     /// Find the index of the item whose range contains the `text_offset`.
@@ -408,7 +404,7 @@ struct LineLayout<'a> {
 
 impl<'a> LineLayout<'a> {
     /// Create a line which spans the given range.
-    fn new(ctx: &mut LayoutContext, par: &'a ParLayouter<'a>, mut line: Range) -> Self {
+    fn new(vm: &mut Vm, par: &'a ParLayouter<'a>, mut line: Range) -> Self {
         // Find the items which bound the text range.
         let last_idx = par.find(line.end.saturating_sub(1)).unwrap();
         let first_idx = if line.is_empty() {
@@ -438,7 +434,7 @@ impl<'a> LineLayout<'a> {
                 // empty string.
                 if !range.is_empty() || rest.is_empty() {
                     // Reshape that part.
-                    let reshaped = shaped.reshape(ctx.fonts, range);
+                    let reshaped = shaped.reshape(vm.fonts, range);
                     last = Some(ParItem::Text(reshaped));
                 }
 
@@ -459,7 +455,7 @@ impl<'a> LineLayout<'a> {
             // Reshape if necessary.
             if range.len() < shaped.text.len() {
                 if !range.is_empty() {
-                    let reshaped = shaped.reshape(ctx.fonts, range);
+                    let reshaped = shaped.reshape(vm.fonts, range);
                     first = Some(ParItem::Text(reshaped));
                 }
 
@@ -504,7 +500,7 @@ impl<'a> LineLayout<'a> {
     }
 
     /// Build the line's frame.
-    fn build(&self, ctx: &LayoutContext, width: Length) -> Frame {
+    fn build(&self, ctx: &Vm, width: Length) -> Frame {
         let size = Size::new(self.size.x.max(width), self.size.y);
         let remaining = size.x - self.size.x;
 
@@ -622,7 +618,7 @@ impl<'a> LineStack<'a> {
     }
 
     /// Finish the frame for one region.
-    fn finish_region(&mut self, ctx: &LayoutContext) {
+    fn finish_region(&mut self, ctx: &Vm) {
         if self.regions.expand.x || self.fractional {
             self.size.x = self.regions.current.x;
             self.cts.exact.x = Some(self.regions.current.x);
@@ -653,7 +649,7 @@ impl<'a> LineStack<'a> {
     }
 
     /// Finish the last region and return the built frames.
-    fn finish(mut self, ctx: &LayoutContext) -> Vec<Constrained<Arc<Frame>>> {
+    fn finish(mut self, ctx: &Vm) -> Vec<Constrained<Arc<Frame>>> {
         self.finish_region(ctx);
         self.finished
     }
diff --git a/src/library/place.rs b/src/library/place.rs
index 52bbeb21..c2c9ac25 100644
--- a/src/library/place.rs
+++ b/src/library/place.rs
@@ -9,7 +9,7 @@ pub struct PlaceNode(pub LayoutNode);
 
 #[class]
 impl PlaceNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let aligns = args.find()?.unwrap_or(Spec::with_x(Some(Align::Left)));
         let tx = args.named("dx")?.unwrap_or_default();
         let ty = args.named("dy")?.unwrap_or_default();
@@ -23,7 +23,7 @@ impl PlaceNode {
 impl Layout for PlaceNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -37,7 +37,7 @@ impl Layout for PlaceNode {
             Regions::one(regions.base, regions.base, expand)
         };
 
-        let mut frames = self.0.layout(ctx, &pod, styles);
+        let mut frames = self.0.layout(vm, &pod, styles);
         let Constrained { item: frame, cts } = &mut frames[0];
 
         // If expansion is off, zero all sizes so that we don't take up any
diff --git a/src/library/raw.rs b/src/library/raw.rs
index e2ae259b..45733fd0 100644
--- a/src/library/raw.rs
+++ b/src/library/raw.rs
@@ -31,7 +31,7 @@ impl RawNode {
     /// The language to syntax-highlight in.
     pub const LANG: Option<EcoString> = None;
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::show(Self {
             text: args.expect("text")?,
             block: args.named("block")?.unwrap_or(false),
diff --git a/src/library/shape.rs b/src/library/shape.rs
index dd306f91..acb011ea 100644
--- a/src/library/shape.rs
+++ b/src/library/shape.rs
@@ -20,7 +20,7 @@ impl<const S: ShapeKind> ShapeNode<S> {
     /// How much to pad the shape's content.
     pub const PADDING: Linear = Linear::zero();
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let size = match S {
             SQUARE => args.named::<Length>("size")?.map(Linear::from),
             CIRCLE => args.named::<Length>("radius")?.map(|r| 2.0 * Linear::from(r)),
@@ -46,7 +46,7 @@ impl<const S: ShapeKind> ShapeNode<S> {
 impl<const S: ShapeKind> Layout for ShapeNode<S> {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -61,7 +61,7 @@ impl<const S: ShapeKind> Layout for ShapeNode<S> {
             let child = child.clone().padded(Sides::splat(padding));
 
             let mut pod = Regions::one(regions.current, regions.base, regions.expand);
-            frames = child.layout(ctx, &pod, styles);
+            frames = child.layout(vm, &pod, styles);
 
             // Relayout with full expansion into square region to make sure
             // the result is really a square or circle.
@@ -77,7 +77,7 @@ impl<const S: ShapeKind> Layout for ShapeNode<S> {
 
                 pod.current = Size::splat(length);
                 pod.expand = Spec::splat(true);
-                frames = child.layout(ctx, &pod, styles);
+                frames = child.layout(vm, &pod, styles);
                 frames[0].cts = Constraints::tight(regions);
             }
         } else {
diff --git a/src/library/spacing.rs b/src/library/spacing.rs
index 3e26cb3c..f9676d4c 100644
--- a/src/library/spacing.rs
+++ b/src/library/spacing.rs
@@ -7,7 +7,7 @@ pub struct HNode;
 
 #[class]
 impl HNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::Horizontal(args.expect("spacing")?))
     }
 }
@@ -17,7 +17,7 @@ pub struct VNode;
 
 #[class]
 impl VNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::Vertical(args.expect("spacing")?))
     }
 }
diff --git a/src/library/stack.rs b/src/library/stack.rs
index 88605a30..287731b8 100644
--- a/src/library/stack.rs
+++ b/src/library/stack.rs
@@ -16,7 +16,7 @@ pub struct StackNode {
 
 #[class]
 impl StackNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::block(Self {
             dir: args.named("dir")?.unwrap_or(Dir::TTB),
             spacing: args.named("spacing")?,
@@ -28,7 +28,7 @@ impl StackNode {
 impl Layout for StackNode {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
@@ -48,7 +48,7 @@ impl Layout for StackNode {
                         layouter.layout_spacing(kind);
                     }
 
-                    layouter.layout_node(ctx, node, styles);
+                    layouter.layout_node(vm, node, styles);
                     deferred = self.spacing;
                 }
             }
@@ -163,12 +163,7 @@ impl StackLayouter {
     }
 
     /// Layout an arbitrary node.
-    pub fn layout_node(
-        &mut self,
-        ctx: &mut LayoutContext,
-        node: &LayoutNode,
-        styles: StyleChain,
-    ) {
+    pub fn layout_node(&mut self, vm: &mut Vm, node: &LayoutNode, styles: StyleChain) {
         if self.regions.is_full() {
             self.finish_region();
         }
@@ -179,7 +174,7 @@ impl StackLayouter {
             .and_then(|node| node.aligns.get(self.axis))
             .unwrap_or(self.dir.start().into());
 
-        let frames = node.layout(ctx, &self.regions, styles);
+        let frames = node.layout(vm, &self.regions, styles);
         let len = frames.len();
         for (i, frame) in frames.into_iter().enumerate() {
             // Grow our size, shrink the region and save the frame for later.
diff --git a/src/library/table.rs b/src/library/table.rs
index 3f30dd9e..dfefa21d 100644
--- a/src/library/table.rs
+++ b/src/library/table.rs
@@ -27,7 +27,7 @@ impl TableNode {
     /// How much to pad the cells's content.
     pub const PADDING: Linear = Length::pt(5.0).into();
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let columns = args.named("columns")?.unwrap_or_default();
         let rows = args.named("rows")?.unwrap_or_default();
         let base_gutter: Vec<TrackSizing> = args.named("gutter")?.unwrap_or_default();
diff --git a/src/library/text.rs b/src/library/text.rs
index 4ee64e7a..9fbc8605 100644
--- a/src/library/text.rs
+++ b/src/library/text.rs
@@ -103,7 +103,7 @@ impl TextNode {
     #[skip]
     pub const LINK: Option<EcoString> = None;
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         // The text constructor is special: It doesn't create a text node.
         // Instead, it leaves the passed argument structurally unchanged, but
         // styles all text in it.
@@ -117,7 +117,7 @@ pub struct StrongNode(pub Template);
 
 #[class]
 impl StrongNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::show(Self(args.expect("body")?)))
     }
 }
@@ -134,7 +134,7 @@ pub struct EmphNode(pub Template);
 
 #[class]
 impl EmphNode {
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         Ok(Template::show(Self(args.expect("body")?)))
     }
 }
diff --git a/src/library/transform.rs b/src/library/transform.rs
index cc40921b..91d4b574 100644
--- a/src/library/transform.rs
+++ b/src/library/transform.rs
@@ -17,7 +17,7 @@ impl<const T: TransformKind> TransformNode<T> {
     /// The origin of the transformation.
     pub const ORIGIN: Spec<Option<Align>> = Spec::default();
 
-    fn construct(_: &mut EvalContext, args: &mut Args) -> TypResult<Template> {
+    fn construct(_: &mut Vm, args: &mut Args) -> TypResult<Template> {
         let transform = match T {
             MOVE => {
                 let tx = args.named("x")?.unwrap_or_default();
@@ -46,12 +46,12 @@ impl<const T: TransformKind> TransformNode<T> {
 impl<const T: TransformKind> Layout for TransformNode<T> {
     fn layout(
         &self,
-        ctx: &mut LayoutContext,
+        vm: &mut Vm,
         regions: &Regions,
         styles: StyleChain,
     ) -> Vec<Constrained<Arc<Frame>>> {
         let origin = styles.get(Self::ORIGIN).unwrap_or(Align::CENTER_HORIZON);
-        let mut frames = self.child.layout(ctx, regions, styles);
+        let mut frames = self.child.layout(vm, regions, styles);
 
         for Constrained { item: frame, .. } in &mut frames {
             let Spec { x, y } = origin.zip(frame.size).map(|(o, s)| o.resolve(s));
diff --git a/src/library/utility.rs b/src/library/utility.rs
index 3b9b8b04..91f0e3ad 100644
--- a/src/library/utility.rs
+++ b/src/library/utility.rs
@@ -7,7 +7,7 @@ use super::prelude::*;
 use crate::eval::Array;
 
 /// Ensure that a condition is fulfilled.
-pub fn assert(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn assert(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect::<Spanned<bool>>("condition")?;
     if !v {
         bail!(span, "assertion failed");
@@ -16,17 +16,17 @@ pub fn assert(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// The name of a value's type.
-pub fn type_(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn type_(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     Ok(args.expect::<Value>("value")?.type_name().into())
 }
 
 /// The string representation of a value.
-pub fn repr(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn repr(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     Ok(args.expect::<Value>("value")?.repr().into())
 }
 
 /// Join a sequence of values, optionally interspersing it with another value.
-pub fn join(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn join(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let span = args.span;
     let sep = args.named::<Value>("sep")?.unwrap_or(Value::None);
 
@@ -46,7 +46,7 @@ pub fn join(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// Convert a value to a integer.
-pub fn int(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn int(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect("value")?;
     Ok(Value::Int(match v {
         Value::Bool(v) => v as i64,
@@ -61,7 +61,7 @@ pub fn int(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// Convert a value to a float.
-pub fn float(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn float(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect("value")?;
     Ok(Value::Float(match v {
         Value::Int(v) => v as f64,
@@ -75,7 +75,7 @@ pub fn float(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// Try to convert a value to a string.
-pub fn str(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn str(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect("value")?;
     Ok(Value::Str(match v {
         Value::Int(v) => format_eco!("{}", v),
@@ -86,7 +86,7 @@ pub fn str(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// Create an RGB(A) color.
-pub fn rgb(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn rgb(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     Ok(Value::from(
         if let Some(string) = args.find::<Spanned<EcoString>>()? {
             match RgbaColor::from_str(&string.v) {
@@ -120,7 +120,7 @@ pub fn rgb(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// Create a CMYK color.
-pub fn cmyk(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn cmyk(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     struct Component(u8);
 
     castable! {
@@ -141,7 +141,7 @@ pub fn cmyk(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// The absolute value of a numeric value.
-pub fn abs(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn abs(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect("numeric value")?;
     Ok(match v {
         Value::Int(v) => Value::Int(v.abs()),
@@ -156,27 +156,27 @@ pub fn abs(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// The minimum of a sequence of values.
-pub fn min(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn min(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     minmax(args, Ordering::Less)
 }
 
 /// The maximum of a sequence of values.
-pub fn max(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn max(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     minmax(args, Ordering::Greater)
 }
 
 /// Whether an integer is even.
-pub fn even(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn even(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     Ok(Value::Bool(args.expect::<i64>("integer")? % 2 == 0))
 }
 
 /// Whether an integer is odd.
-pub fn odd(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn odd(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     Ok(Value::Bool(args.expect::<i64>("integer")? % 2 != 0))
 }
 
 /// The modulo of two numbers.
-pub fn modulo(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn modulo(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let Spanned { v: v1, span: span1 } = args.expect("integer or float")?;
     let Spanned { v: v2, span: span2 } = args.expect("integer or float")?;
 
@@ -227,7 +227,7 @@ fn minmax(args: &mut Args, goal: Ordering) -> TypResult<Value> {
 }
 
 /// Create a sequence of numbers.
-pub fn range(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn range(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let first = args.expect::<i64>("end")?;
     let (start, end) = match args.eat::<i64>()? {
         Some(second) => (first, second),
@@ -252,19 +252,19 @@ pub fn range(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// Convert a string to lowercase.
-pub fn lower(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn lower(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     Ok(args.expect::<EcoString>("string")?.to_lowercase().into())
 }
 
 /// Convert a string to uppercase.
-pub fn upper(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn upper(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     Ok(args.expect::<EcoString>("string")?.to_uppercase().into())
 }
 
 /// Converts an integer into a roman numeral.
 ///
 /// Works for integer between 0 and 3,999,999.
-pub fn roman(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn roman(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     // Adapted from Yann Villessuzanne's roman.rs under the Unlicense, at
     // https://github.com/linfir/roman.rs/
     static PAIRS: &'static [(&'static str, usize)] = &[
@@ -314,7 +314,7 @@ pub fn roman(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// Convert a number into a roman numeral.
-pub fn symbol(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn symbol(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     static SYMBOLS: &'static [char] = &['*', '†', '‡', '§', '‖', '¶'];
 
     let n = args.expect::<usize>("non-negative integer")?;
@@ -327,7 +327,7 @@ pub fn symbol(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// The length of a string, an array or a dictionary.
-pub fn len(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn len(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect("collection")?;
     Ok(Value::Int(match v {
         Value::Str(v) => v.len() as i64,
@@ -342,7 +342,7 @@ pub fn len(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
 }
 
 /// The sorted version of an array.
-pub fn sorted(_: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
+pub fn sorted(_: &mut Vm, args: &mut Args) -> TypResult<Value> {
     let Spanned { v, span } = args.expect::<Spanned<Array>>("array")?;
     Ok(Value::Array(v.sorted().at(span)?))
 }