Make AST borrowed

crates/typst-syntax/src/node.rs

@@ -105,22 +105,22 @@ impl SyntaxNode {
     }
 
     /// Whether the node can be cast to the given AST node.
-    pub fn is<T: AstNode>(&self) -> bool {
+    pub fn is<'a, T: AstNode<'a>>(&'a self) -> bool {
         self.cast::<T>().is_some()
     }
 
     /// Try to convert the node to a typed AST node.
-    pub fn cast<T: AstNode>(&self) -> Option<T> {
+    pub fn cast<'a, T: AstNode<'a>>(&'a self) -> Option<T> {
         T::from_untyped(self)
     }
 
     /// Cast the first child that can cast to the AST type `T`.
-    pub fn cast_first_match<T: AstNode>(&self) -> Option<T> {
+    pub fn cast_first_match<'a, T: AstNode<'a>>(&'a self) -> Option<T> {
         self.children().find_map(Self::cast)
     }
 
     /// Cast the last child that can cast to the AST type `T`.
-    pub fn cast_last_match<T: AstNode>(&self) -> Option<T> {
+    pub fn cast_last_match<'a, T: AstNode<'a>>(&'a self) -> Option<T> {
         self.children().rev().find_map(Self::cast)
     }
 
@@ -273,6 +273,17 @@ impl SyntaxNode {
             Repr::Error(node) => node.error.span.number() + 1,
         }
     }
+
+    /// An arbitrary node just for filling a slot in memory.
+    ///
+    /// In contrast to `default()`, this is a const fn.
+    pub(super) const fn arbitrary() -> Self {
+        Self(Repr::Leaf(LeafNode {
+            kind: SyntaxKind::Eof,
+            text: EcoString::new(),
+            span: Span::detached(),
+        }))
+    }
 }
 
 impl Debug for SyntaxNode {
@@ -287,7 +298,7 @@ impl Debug for SyntaxNode {
 
 impl Default for SyntaxNode {
     fn default() -> Self {
-        Self::error("", "")
+        Self::arbitrary()
     }
 }
 
@@ -802,6 +813,8 @@ impl<'a> LinkedNode<'a> {
 impl Deref for LinkedNode<'_> {
     type Target = SyntaxNode;
 
+    /// Dereference to a syntax node. Note that this shortens the lifetime, so
+    /// you may need to use [`get()`](Self::get) instead in some situations.
     fn deref(&self) -> &Self::Target {
         self.get()
     }

crates/typst/src/eval/func.rs

@@ -12,7 +12,7 @@ use super::{
 };
 use crate::diag::{bail, SourceResult, StrResult};
 use crate::model::{DelayedErrors, ElemFunc, Introspector, Locator, Vt};
-use crate::syntax::ast::{self, AstNode, Expr, Ident};
+use crate::syntax::ast::{self, AstNode};
 use crate::syntax::{FileId, Span, SyntaxNode};
 use crate::World;
 
@@ -45,7 +45,7 @@ impl Func {
         match &self.repr {
             Repr::Native(native) => Some(native.info.name),
             Repr::Elem(func) => Some(func.info().name),
-            Repr::Closure(closure) => closure.name.as_deref(),
+            Repr::Closure(closure) => closure.name(),
             Repr::With(arc) => arc.0.name(),
         }
     }
@@ -295,36 +295,32 @@ pub struct ParamInfo {
 /// A user-defined closure.
 #[derive(Hash)]
 pub(super) struct Closure {
+    /// The closure's syntax node. Must be castable to `ast::Closure`.
+    pub node: SyntaxNode,
     /// The source file where the closure was defined.
     pub location: FileId,
-    /// The name of the closure.
-    pub name: Option<Ident>,
+    /// Default values of named parameters.
+    pub defaults: Vec<Value>,
     /// Captured values from outer scopes.
     pub captured: Scope,
-    /// The list of parameters.
-    pub params: Vec<Param>,
-    /// The expression the closure should evaluate to.
-    pub body: Expr,
-}
-
-/// A closure parameter.
-#[derive(Hash)]
-pub enum Param {
-    /// A positional parameter: `x`.
-    Pos(ast::Pattern),
-    /// A named parameter with a default value: `draw: false`.
-    Named(Ident, Value),
-    /// An argument sink: `..args`.
-    Sink(Option<Ident>),
 }
 
 impl Closure {
+    /// The name of the closure.
+    pub fn name(&self) -> Option<&str> {
+        self.node
+            .cast::<ast::Closure>()
+            .unwrap()
+            .name()
+            .map(|ident| ident.as_str())
+    }
+
     /// Call the function in the context with the arguments.
     #[comemo::memoize]
     #[tracing::instrument(skip_all)]
     #[allow(clippy::too_many_arguments)]
     fn call(
-        this: &Func,
+        func: &Func,
         world: Tracked<dyn World + '_>,
         route: Tracked<Route>,
         introspector: Tracked<Introspector>,
@@ -334,15 +330,15 @@ impl Closure {
         depth: usize,
         mut args: Args,
     ) -> SourceResult<Value> {
-        let closure = match &this.repr {
-            Repr::Closure(closure) => closure,
-            _ => panic!("`this` must be a closure"),
+        let Repr::Closure(this) = &func.repr else {
+            panic!("`this` must be a closure");
         };
+        let closure = this.node.cast::<ast::Closure>().unwrap();
 
         // Don't leak the scopes from the call site. Instead, we use the scope
         // of captured variables we collected earlier.
         let mut scopes = Scopes::new(None);
-        scopes.top = closure.captured.clone();
+        scopes.top = this.captured.clone();
 
         // Prepare VT.
         let mut locator = Locator::chained(locator);
@@ -355,30 +351,34 @@ impl Closure {
         };
 
         // Prepare VM.
-        let mut vm = Vm::new(vt, route, closure.location, scopes);
+        let mut vm = Vm::new(vt, route, this.location, scopes);
         vm.depth = depth;
 
         // Provide the closure itself for recursive calls.
-        if let Some(name) = &closure.name {
-            vm.define(name.clone(), Value::Func(this.clone()));
+        if let Some(name) = closure.name() {
+            vm.define(name, Value::Func(func.clone()));
         }
 
         // Parse the arguments according to the parameter list.
-        let num_pos_params =
-            closure.params.iter().filter(|p| matches!(p, Param::Pos(_))).count();
+        let num_pos_params = closure
+            .params()
+            .children()
+            .filter(|p| matches!(p, ast::Param::Pos(_)))
+            .count();
         let num_pos_args = args.to_pos().len();
         let sink_size = num_pos_args.checked_sub(num_pos_params);
 
         let mut sink = None;
         let mut sink_pos_values = None;
-        for p in &closure.params {
+        let mut defaults = this.defaults.iter();
+        for p in closure.params().children() {
             match p {
-                Param::Pos(pattern) => match pattern {
+                ast::Param::Pos(pattern) => match pattern {
                     ast::Pattern::Normal(ast::Expr::Ident(ident)) => {
-                        vm.define(ident.clone(), args.expect::<Value>(ident)?)
+                        vm.define(ident, args.expect::<Value>(&ident)?)
                     }
                     ast::Pattern::Normal(_) => unreachable!(),
-                    _ => {
+                    pattern => {
                         super::define_pattern(
                             &mut vm,
                             pattern,
@@ -386,16 +386,18 @@ impl Closure {
                         )?;
                     }
                 },
-                Param::Sink(ident) => {
-                    sink = ident.clone();
+                ast::Param::Sink(ident) => {
+                    sink = ident.name();
                     if let Some(sink_size) = sink_size {
                         sink_pos_values = Some(args.consume(sink_size)?);
                     }
                 }
-                Param::Named(ident, default) => {
+                ast::Param::Named(named) => {
+                    let name = named.name();
+                    let default = defaults.next().unwrap();
                     let value =
-                        args.named::<Value>(ident)?.unwrap_or_else(|| default.clone());
-                    vm.define(ident.clone(), value);
+                        args.named::<Value>(&name)?.unwrap_or_else(|| default.clone());
+                    vm.define(name, value);
                 }
             }
         }
@@ -412,7 +414,7 @@ impl Closure {
         args.finish()?;
 
         // Handle control flow.
-        let result = closure.body.eval(&mut vm);
+        let result = closure.body().eval(&mut vm);
         match vm.flow {
             Some(FlowEvent::Return(_, Some(explicit))) => return Ok(explicit),
             Some(FlowEvent::Return(_, None)) => {}
@@ -483,7 +485,7 @@ impl<'a> CapturesVisitor<'a> {
             Some(ast::Expr::Closure(expr)) => {
                 for param in expr.params().children() {
                     if let ast::Param::Named(named) = param {
-                        self.visit(named.expr().as_untyped());
+                        self.visit(named.expr().to_untyped());
                     }
                 }
 
@@ -506,7 +508,7 @@ impl<'a> CapturesVisitor<'a> {
                     }
                 }
 
-                self.visit(expr.body().as_untyped());
+                self.visit(expr.body().to_untyped());
                 self.internal.exit();
             }
 
@@ -514,7 +516,7 @@ impl<'a> CapturesVisitor<'a> {
             // active after the body is evaluated.
             Some(ast::Expr::Let(expr)) => {
                 if let Some(init) = expr.init() {
-                    self.visit(init.as_untyped());
+                    self.visit(init.to_untyped());
                 }
 
                 for ident in expr.kind().idents() {
@@ -526,7 +528,7 @@ impl<'a> CapturesVisitor<'a> {
             // active after the iterable is evaluated but before the body is
             // evaluated.
             Some(ast::Expr::For(expr)) => {
-                self.visit(expr.iter().as_untyped());
+                self.visit(expr.iter().to_untyped());
                 self.internal.enter();
 
                 let pattern = expr.pattern();
@@ -534,16 +536,16 @@ impl<'a> CapturesVisitor<'a> {
                     self.bind(ident);
                 }
 
-                self.visit(expr.body().as_untyped());
+                self.visit(expr.body().to_untyped());
                 self.internal.exit();
             }
 
             // An import contains items, but these are active only after the
             // path is evaluated.
             Some(ast::Expr::Import(expr)) => {
-                self.visit(expr.source().as_untyped());
+                self.visit(expr.source().to_untyped());
                 if let Some(ast::Imports::Items(items)) = expr.imports() {
-                    for item in items {
+                    for item in items.idents() {
                         self.bind(item);
                     }
                 }
@@ -560,14 +562,14 @@ impl<'a> CapturesVisitor<'a> {
 
     /// Bind a new internal variable.
     fn bind(&mut self, ident: ast::Ident) {
-        self.internal.top.define(ident.take(), Value::None);
+        self.internal.top.define(ident.get().clone(), Value::None);
     }
 
     /// Capture a variable if it isn't internal.
     fn capture(&mut self, ident: ast::Ident) {
         if self.internal.get(&ident).is_err() {
             if let Ok(value) = self.external.get(&ident) {
-                self.captures.define_captured(ident.take(), value.clone());
+                self.captures.define_captured(ident.get().clone(), value.clone());
             }
         }
     }
@@ -576,7 +578,7 @@ impl<'a> CapturesVisitor<'a> {
     fn capture_in_math(&mut self, ident: ast::MathIdent) {
         if self.internal.get(&ident).is_err() {
             if let Ok(value) = self.external.get_in_math(&ident) {
-                self.captures.define_captured(ident.take(), value.clone());
+                self.captures.define_captured(ident.get().clone(), value.clone());
             }
         }
     }

crates/typst/src/ide/complete.rs

@@ -442,13 +442,13 @@ fn complete_imports(ctx: &mut CompletionContext) -> bool {
     // "#import "path.typ": a, b, |".
     if_chain! {
         if let Some(prev) = ctx.leaf.prev_sibling();
-        if let Some(ast::Expr::Import(import)) = prev.cast();
+        if let Some(ast::Expr::Import(import)) = prev.get().cast();
         if let Some(ast::Imports::Items(items)) = import.imports();
         if let Some(source) = prev.children().find(|child| child.is::<ast::Expr>());
         if let Some(value) = analyze_expr(ctx.world, &source).into_iter().next();
         then {
             ctx.from = ctx.cursor;
-            import_item_completions(ctx, &items, &value);
+            import_item_completions(ctx, items, &value);
             return true;
         }
     }
@@ -460,13 +460,13 @@ fn complete_imports(ctx: &mut CompletionContext) -> bool {
         if let Some(parent) = ctx.leaf.parent();
         if parent.kind() == SyntaxKind::ImportItems;
         if let Some(grand) = parent.parent();
-        if let Some(ast::Expr::Import(import)) = grand.cast();
+        if let Some(ast::Expr::Import(import)) = grand.get().cast();
         if let Some(ast::Imports::Items(items)) = import.imports();
         if let Some(source) = grand.children().find(|child| child.is::<ast::Expr>());
         if let Some(value) = analyze_expr(ctx.world, &source).into_iter().next();
         then {
             ctx.from = ctx.leaf.offset();
-            import_item_completions(ctx, &items, &value);
+            import_item_completions(ctx, items, &value);
             return true;
         }
     }
@@ -475,9 +475,9 @@ fn complete_imports(ctx: &mut CompletionContext) -> bool {
 }
 
 /// Add completions for all exports of a module.
-fn import_item_completions(
-    ctx: &mut CompletionContext,
-    existing: &[ast::Ident],
+fn import_item_completions<'a>(
+    ctx: &mut CompletionContext<'a>,
+    existing: ast::ImportItems<'a>,
     value: &Value,
 ) {
     let module = match value {
@@ -489,12 +489,12 @@ fn import_item_completions(
         _ => return,
     };
 
-    if existing.is_empty() {
+    if existing.idents().next().is_none() {
         ctx.snippet_completion("*", "*", "Import everything.");
     }
 
     for (name, value) in module.scope().iter() {
-        if existing.iter().all(|ident| ident.as_str() != name) {
+        if existing.idents().all(|ident| ident.as_str() != name) {
             ctx.value_completion(Some(name.clone()), value, false, None);
         }
     }
@@ -604,9 +604,9 @@ fn complete_params(ctx: &mut CompletionContext) -> bool {
             SyntaxKind::Named => parent.parent(),
             _ => Some(parent),
         };
-        if let Some(args) = parent.cast::<ast::Args>();
+        if let Some(args) = parent.get().cast::<ast::Args>();
         if let Some(grand) = parent.parent();
-        if let Some(expr) = grand.cast::<ast::Expr>();
+        if let Some(expr) = grand.get().cast::<ast::Expr>();
         let set = matches!(expr, ast::Expr::Set(_));
         if let Some(callee) = match expr {
             ast::Expr::FuncCall(call) => Some(call.callee()),
@@ -634,13 +634,13 @@ fn complete_params(ctx: &mut CompletionContext) -> bool {
     if_chain! {
         if deciding.kind() == SyntaxKind::Colon;
         if let Some(prev) = deciding.prev_leaf();
-        if let Some(param) = prev.cast::<ast::Ident>();
+        if let Some(param) = prev.get().cast::<ast::Ident>();
         then {
             if let Some(next) = deciding.next_leaf() {
                 ctx.from = ctx.cursor.min(next.offset());
             }
 
-            named_param_value_completions(ctx, &callee, &param);
+            named_param_value_completions(ctx, callee, &param);
             return true;
         }
     }
@@ -655,12 +655,15 @@ fn complete_params(ctx: &mut CompletionContext) -> bool {
             }
 
             // Exclude arguments which are already present.
-            let exclude: Vec<_> = args.items().filter_map(|arg| match arg {
-                ast::Arg::Named(named) => Some(named.name()),
-                _ => None,
-            }).collect();
+            let exclude: Vec<_> = args
+                .items()
+                .filter_map(|arg| match arg {
+                    ast::Arg::Named(named) => Some(named.name()),
+                    _ => None,
+                })
+                .collect();
 
-            param_completions(ctx, &callee, set, &exclude);
+            param_completions(ctx, callee, set, &exclude);
             return true;
         }
     }
@@ -669,11 +672,11 @@ fn complete_params(ctx: &mut CompletionContext) -> bool {
 }
 
 /// Add completions for the parameters of a function.
-fn param_completions(
-    ctx: &mut CompletionContext,
-    callee: &ast::Expr,
+fn param_completions<'a>(
+    ctx: &mut CompletionContext<'a>,
+    callee: ast::Expr<'a>,
     set: bool,
-    exclude: &[ast::Ident],
+    exclude: &[ast::Ident<'a>],
 ) {
     let Some(func) = resolve_global_callee(ctx, callee) else { return };
     let Some(info) = func.info() else { return };
@@ -707,9 +710,9 @@ fn param_completions(
 }
 
 /// Add completions for the values of a named function parameter.
-fn named_param_value_completions(
-    ctx: &mut CompletionContext,
-    callee: &ast::Expr,
+fn named_param_value_completions<'a>(
+    ctx: &mut CompletionContext<'a>,
+    callee: ast::Expr<'a>,
     name: &str,
 ) {
     let Some(func) = resolve_global_callee(ctx, callee) else { return };
@@ -732,10 +735,10 @@ fn named_param_value_completions(
 /// Resolve a callee expression to a global function.
 fn resolve_global_callee<'a>(
     ctx: &CompletionContext<'a>,
-    callee: &ast::Expr,
+    callee: ast::Expr<'a>,
 ) -> Option<&'a Func> {
     let value = match callee {
-        ast::Expr::Ident(ident) => ctx.global.get(ident)?,
+        ast::Expr::Ident(ident) => ctx.global.get(&ident)?,
         ast::Expr::FieldAccess(access) => match access.target() {
             ast::Expr::Ident(target) => match ctx.global.get(&target)? {
                 Value::Module(module) => module.get(&access.field()).ok()?,
@@ -1189,20 +1192,20 @@ impl<'a> CompletionContext<'a> {
         while let Some(node) = &ancestor {
             let mut sibling = Some(node.clone());
             while let Some(node) = &sibling {
-                if let Some(v) = node.cast::<ast::LetBinding>() {
+                if let Some(v) = node.get().cast::<ast::LetBinding>() {
                     for ident in v.kind().idents() {
-                        defined.insert(ident.take());
+                        defined.insert(ident.get());
                     }
                 }
                 sibling = node.prev_sibling();
             }
 
             if let Some(parent) = node.parent() {
-                if let Some(v) = parent.cast::<ast::ForLoop>() {
+                if let Some(v) = parent.get().cast::<ast::ForLoop>() {
                     if node.prev_sibling_kind() != Some(SyntaxKind::In) {
                         let pattern = v.pattern();
                         for ident in pattern.idents() {
-                            defined.insert(ident.take());
+                            defined.insert(ident.get());
                         }
                     }
                 }
@@ -1233,7 +1236,7 @@ impl<'a> CompletionContext<'a> {
             if !name.is_empty() {
                 self.completions.push(Completion {
                     kind: CompletionKind::Constant,
-                    label: name,
+                    label: name.clone(),
                     apply: None,
                     detail: None,
                 });