i_slint_compiler/

lookup.rs

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0

//! Helper to do lookup in expressions

use std::rc::Rc;
use std::sync::Arc;

use crate::diagnostics::{BuildDiagnostics, Spanned};
use crate::expression_tree::{
    BuiltinFunction, BuiltinMacroFunction, Callable, EasingCurve, Expression, MouseCursorInner,
    Unit,
};
use crate::langtype::{ElementType, Enumeration, EnumerationValue, PropertyLookupMode, Type};
use crate::namedreference::NamedReference;
use crate::object_tree::{ElementRc, PropertyVisibility};
use crate::parser::{NodeOrToken, TextRange, TextSize};
use crate::symbol_counters::SymbolCounters;
use crate::typeregister::TypeRegister;
use smol_str::{SmolStr, format_smolstr};
use std::cell::RefCell;

pub use i_slint_common::color_parsing::named_colors;

/// Contains information which allow to lookup identifier in expressions
pub struct LookupCtx<'a> {
    /// the name of the property for which this expression refers.
    pub property_name: Option<&'a str>,

    /// the type of the property for which this expression refers.
    /// (some property come in the scope)
    pub property_type: Type,

    /// The expected type at the current position within the expression, updated as the
    /// resolver descends into struct fields, array elements and call arguments. Unlike
    /// `property_type` (the whole binding's type) it drives type-directed name resolution
    /// (color/easing/enum literals) at that exact position.
    pub expected_type: Type,

    /// Here is the stack in which id applies. (the last element in the scope is looked up first)
    pub component_scope: &'a [ElementRc],

    /// Somewhere to report diagnostics
    pub diag: &'a mut BuildDiagnostics,

    /// Counters for generating unique symbol names (shared across the compilation).
    pub symbol_counters: Rc<SymbolCounters>,

    /// The name of the arguments of the callback or function
    pub arguments: Vec<SmolStr>,

    /// The type register in which to look for Globals
    pub type_register: &'a TypeRegister,

    /// The type loader instance, which may be used to resolve relative path references
    /// for example for img!
    pub type_loader: Option<&'a crate::typeloader::TypeLoader>,

    /// The token currently processed
    pub current_token: Option<NodeOrToken>,

    /// A stack of local variable scopes
    pub local_variables: Vec<Vec<(SmolStr, Type)>>,

    /// LSP probe: while resolving, the `Type` is set to the `expected_type` at the innermost
    /// node containing the offset. `None` during normal compilation.
    pub expected_type_probe: Option<(TextSize, Type)>,
}

impl<'a> LookupCtx<'a> {
    /// Return a context that is just suitable to build simple const expression
    pub fn empty_context(
        type_register: &'a TypeRegister,
        diag: &'a mut BuildDiagnostics,
        symbol_counters: Rc<SymbolCounters>,
    ) -> Self {
        Self {
            property_name: Default::default(),
            property_type: Default::default(),
            expected_type: Default::default(),
            component_scope: Default::default(),
            diag,
            symbol_counters,
            arguments: Default::default(),
            type_register,
            type_loader: None,
            current_token: None,
            local_variables: Default::default(),
            expected_type_probe: None,
        }
    }

    pub fn return_type(&self) -> &Type {
        match &self.property_type {
            Type::Callback(f) | Type::Function(f) => &f.return_type,
            _ => &self.property_type,
        }
    }

    /// Whether lookup offers experimental entries: enabled experimental features,
    /// or the builtin widget library, which may use them.
    fn experimental_lookup_enabled(&self) -> bool {
        self.diag.enable_experimental || self.type_register.expose_internal_types
    }

    /// Arm the LSP probe at `offset`, seeded with the current `expected_type` as fallback.
    pub fn set_expected_type_probe(&mut self, offset: TextSize) {
        self.expected_type_probe = Some((offset, self.expected_type.clone()));
    }

    /// The armed probe's offset, or `None` during normal compilation.
    pub fn expected_type_probe_offset(&self) -> Option<TextSize> {
        self.expected_type_probe.as_ref().map(|(offset, _)| *offset)
    }

    /// Disarm the probe and return the type recorded at its offset.
    pub fn take_expected_type_probe(&mut self) -> Option<Type> {
        self.expected_type_probe.take().map(|(_, ty)| ty)
    }

    /// Record `ty` on the probe when its offset is in `range` — for a slot with no expression
    /// node (the empty element/argument left by a trailing comma).
    pub fn record_expected_type_probe(&mut self, range: TextRange, ty: &Type) {
        if let Some((offset, slot)) = &mut self.expected_type_probe
            && range.contains_inclusive(*offset)
        {
            *slot = ty.clone();
        }
    }

    /// Run `f` with `expected_type` temporarily set to `ty`, restoring it afterwards.
    pub fn with_expected_type<R>(&mut self, ty: Type, f: impl FnOnce(&mut Self) -> R) -> R {
        let old = std::mem::replace(&mut self.expected_type, ty);
        let r = f(self);
        self.expected_type = old;
        r
    }

    pub fn is_legacy_component(&self) -> bool {
        self.component_scope.first().is_some_and(|e| e.borrow().is_legacy_syntax)
    }

    /// True if the element is in the same component as the scope
    pub fn is_local_element(&self, elem: &ElementRc) -> bool {
        Option::zip(
            elem.borrow().enclosing_component.upgrade(),
            self.component_scope.first().and_then(|x| x.borrow().enclosing_component.upgrade()),
        )
        .is_none_or(|(x, y)| Rc::ptr_eq(&x, &y))
    }
}

#[derive(Debug)]
pub enum LookupResult {
    Expression {
        expression: Expression,
        /// When set, this is deprecated, and the string is the hint message shown after
        /// "The property 'xxx' has been deprecated." (e.g. "Please use 'yyy' instead")
        deprecated: Option<SmolStr>,
    },
    Enumeration(Arc<Enumeration>),
    Namespace(BuiltinNamespace),
    Callable(LookupResultCallable),
}

#[derive(Debug)]
pub enum LookupResultCallable {
    Callable(Callable),
    Macro(BuiltinMacroFunction),
    /// for example for `item.focus`, where `item` is the base
    MemberFunction {
        /// This becomes the first argument of the function call
        base: Expression,
        /// Syntax node used as the diagnostic source span for `base`. In practice this is
        /// often the node that originated the member-function lookup (e.g. the `.focus`
        /// token), not the node of `base` itself.
        source_node: Option<NodeOrToken>,
        member: Box<LookupResultCallable>,
    },
}

#[derive(Debug, derive_more::Display)]
pub enum BuiltinNamespace {
    Colors,
    Easing,
    Math,
    Key,
    FontWeight,
    MouseCursor,
    SlintInternal,
}

impl From<Expression> for LookupResult {
    fn from(expression: Expression) -> Self {
        Self::Expression { expression, deprecated: None }
    }
}
impl From<Callable> for LookupResult {
    fn from(callable: Callable) -> Self {
        Self::Callable(LookupResultCallable::Callable(callable))
    }
}
impl From<BuiltinMacroFunction> for LookupResult {
    fn from(macro_function: BuiltinMacroFunction) -> Self {
        Self::Callable(LookupResultCallable::Macro(macro_function))
    }
}
impl From<BuiltinFunction> for LookupResult {
    fn from(function: BuiltinFunction) -> Self {
        Self::Callable(LookupResultCallable::Callable(Callable::Builtin(function)))
    }
}

impl LookupResult {
    pub fn deprecated(&self) -> Option<&str> {
        match self {
            Self::Expression { deprecated: Some(x), .. } => Some(x.as_str()),
            _ => None,
        }
    }
}

/// Represent an object which has properties which can be accessible
pub trait LookupObject {
    /// Will call the function for each entry (useful for completion)
    /// If the function return Some, it will immediately be returned and not called further
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R>;

    /// Perform a lookup of a given identifier.
    /// One does not have to re-implement unless we can make it faster
    fn lookup(&self, ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        self.for_each_entry(ctx, &mut |prop, expr| (prop == name).then_some(expr))
    }
}

impl<T1: LookupObject, T2: LookupObject> LookupObject for (T1, T2) {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        self.0.for_each_entry(ctx, f).or_else(|| self.1.for_each_entry(ctx, f))
    }

    fn lookup(&self, ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        self.0.lookup(ctx, name).or_else(|| self.1.lookup(ctx, name))
    }
}

impl LookupObject for LookupResult {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        match self {
            LookupResult::Expression { expression, .. } => expression.for_each_entry(ctx, f),
            LookupResult::Enumeration(e) => e.for_each_entry(ctx, f),
            LookupResult::Namespace(BuiltinNamespace::Colors) => {
                (ColorSpecific, ColorFunctions).for_each_entry(ctx, f)
            }
            LookupResult::Namespace(BuiltinNamespace::Easing) => {
                EasingSpecific.for_each_entry(ctx, f)
            }
            LookupResult::Namespace(BuiltinNamespace::Math) => MathFunctions.for_each_entry(ctx, f),
            LookupResult::Namespace(BuiltinNamespace::Key) => KeysLookup.for_each_entry(ctx, f),
            LookupResult::Namespace(BuiltinNamespace::FontWeight) => {
                FontWeightLookup.for_each_entry(ctx, f)
            }
            LookupResult::Namespace(BuiltinNamespace::MouseCursor) => {
                MouseCursorSpecific.for_each_entry(ctx, f)
            }
            LookupResult::Namespace(BuiltinNamespace::SlintInternal) => {
                SlintInternal.for_each_entry(ctx, f)
            }
            LookupResult::Callable(..) => None,
        }
    }

    fn lookup(&self, ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        match self {
            LookupResult::Expression { expression, .. } => expression.lookup(ctx, name),
            LookupResult::Enumeration(e) => e.lookup(ctx, name),
            LookupResult::Namespace(BuiltinNamespace::Colors) => {
                (ColorSpecific, ColorFunctions).lookup(ctx, name)
            }
            LookupResult::Namespace(BuiltinNamespace::Easing) => EasingSpecific.lookup(ctx, name),
            LookupResult::Namespace(BuiltinNamespace::Math) => MathFunctions.lookup(ctx, name),
            LookupResult::Namespace(BuiltinNamespace::Key) => KeysLookup.lookup(ctx, name),
            LookupResult::Namespace(BuiltinNamespace::FontWeight) => {
                FontWeightLookup.lookup(ctx, name)
            }
            LookupResult::Namespace(BuiltinNamespace::MouseCursor) => {
                MouseCursorSpecific.lookup(ctx, name)
            }
            LookupResult::Namespace(BuiltinNamespace::SlintInternal) => {
                SlintInternal.lookup(ctx, name)
            }
            LookupResult::Callable(..) => None,
        }
    }
}

struct LocalVariableLookup;
impl LookupObject for LocalVariableLookup {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        for scope in ctx.local_variables.iter().rev() {
            for (name, ty) in scope.iter().rev() {
                if let Some(r) = f(
                    // we need to strip the "local_" prefix because a lookup call will not include it
                    &name.strip_prefix("local_").unwrap_or(name).into(),
                    Expression::ReadLocalVariable { name: name.clone(), ty: ty.clone() }.into(),
                ) {
                    return Some(r);
                }
            }
        }
        None
    }
}

struct ArgumentsLookup;
impl LookupObject for ArgumentsLookup {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let args = match &ctx.property_type {
            Type::Callback(f) | Type::Function(f) => &f.args,
            _ => return None,
        };
        for (index, (name, ty)) in ctx.arguments.iter().zip(args.iter()).enumerate() {
            if let Some(r) =
                f(name, Expression::FunctionParameterReference { index, ty: ty.clone() }.into())
            {
                return Some(r);
            }
        }
        None
    }
}

struct SpecialIdLookup;
impl LookupObject for SpecialIdLookup {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let last = ctx.component_scope.last();
        let mut f = |n, e: Expression| f(&SmolStr::new_static(n), e.into());
        None.or_else(|| f("self", Expression::ElementReference(Rc::downgrade(last?))))
            .or_else(|| {
                let len = ctx.component_scope.len();
                if len >= 2 {
                    f(
                        "parent",
                        Expression::ElementReference(Rc::downgrade(&ctx.component_scope[len - 2])),
                    )
                } else {
                    None
                }
            })
            .or_else(|| f("true", Expression::BoolLiteral(true)))
            .or_else(|| f("false", Expression::BoolLiteral(false)))
        // "root" is just a normal id
    }
}

struct IdLookup;
impl LookupObject for IdLookup {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        fn visit<R>(
            root: &ElementRc,
            f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
        ) -> Option<R> {
            if !root.borrow().id.is_empty()
                && let Some(r) =
                    f(&root.borrow().id, Expression::ElementReference(Rc::downgrade(root)).into())
            {
                return Some(r);
            }
            for x in &root.borrow().children {
                if x.borrow().repeated.is_some() {
                    continue;
                }
                if let Some(r) = visit(x, f) {
                    return Some(r);
                }
            }
            None
        }
        for e in ctx.component_scope.iter().rev() {
            if e.borrow().repeated.is_some()
                && let Some(r) = visit(e, f)
            {
                return Some(r);
            }
        }
        if let Some(root) = ctx.component_scope.first()
            && let Some(r) = visit(root, f)
        {
            return Some(r);
        }
        None
    }
    // TODO: hash based lookup
}

/// In-scope properties, or model
pub struct InScopeLookup;
impl InScopeLookup {
    fn visit_scope<R>(
        ctx: &LookupCtx,
        mut visit_entry: impl FnMut(&SmolStr, LookupResult) -> Option<R>,
        mut visit_legacy_scope: impl FnMut(&ElementRc) -> Option<R>,
        mut visit_scope: impl FnMut(&ElementRc) -> Option<R>,
    ) -> Option<R> {
        let is_legacy = ctx.is_legacy_component();
        for (idx, elem) in ctx.component_scope.iter().rev().enumerate() {
            if let Some(repeated) = &elem.borrow().repeated {
                if !repeated.index_id.is_empty()
                    && let Some(r) = visit_entry(
                        &repeated.index_id,
                        Expression::RepeaterIndexReference { element: Rc::downgrade(elem) }.into(),
                    )
                {
                    return Some(r);
                }
                if !repeated.model_data_id.is_empty()
                    && let Some(r) = visit_entry(
                        &repeated.model_data_id,
                        Expression::RepeaterModelReference { element: Rc::downgrade(elem) }.into(),
                    )
                {
                    return Some(r);
                }
            }

            if is_legacy {
                if (elem.borrow().repeated.is_some()
                    || idx == 0
                    || idx == ctx.component_scope.len() - 1)
                    && let Some(r) = visit_legacy_scope(elem)
                {
                    return Some(r);
                }
            } else if let Some(r) = visit_scope(elem) {
                return Some(r);
            }
        }
        None
    }
}
impl LookupObject for InScopeLookup {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let f = RefCell::new(f);
        Self::visit_scope(
            ctx,
            |str, r| f.borrow_mut()(str, r),
            |elem| elem.for_each_entry(ctx, *f.borrow_mut()),
            |elem| {
                for (internal_name, prop) in &elem.borrow().property_declarations {
                    let e = expression_from_reference(
                        NamedReference::new(elem, internal_name.clone()),
                        &prop.property_type,
                        None,
                    );
                    if let Some(r) = f.borrow_mut()(prop.declared_name(internal_name), e) {
                        return Some(r);
                    }
                }
                None
            },
        )
    }

    fn lookup(&self, ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        if name.is_empty() {
            return None;
        }
        Self::visit_scope(
            ctx,
            |str, r| (str == name).then_some(r),
            |elem| elem.lookup(ctx, name),
            |elem| {
                let elem_borrow = elem.borrow();
                elem_borrow.declaration(name).map(|(internal_name, prop)| {
                    expression_from_reference(
                        NamedReference::new(elem, internal_name.clone()),
                        &prop.property_type,
                        None,
                    )
                })
            },
        )
    }
}

impl LookupObject for ElementRc {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        for (internal_name, prop) in &self.borrow().property_declarations {
            let name = prop.declared_name(internal_name);
            let r = expression_from_reference(
                NamedReference::new(self, internal_name.clone()),
                &prop.property_type,
                check_extra_deprecated(self, ctx, name),
            );
            if let Some(r) = f(name, r) {
                return Some(r);
            }
        }
        // NamedReference::new borrows the element, so the check can't hold a borrow across the loop
        let has_shadows = !self.borrow().shadowing_members.is_empty();
        let list = self.borrow().base_type.property_list();
        for (name, ty) in list {
            // A shadowing declaration above already offered this name
            if has_shadows && self.borrow().shadowing_members.contains_key(&name) {
                continue;
            }
            // Resolve the source name to the storage key so a shadow in a base resolves correctly.
            let key = self
                .borrow()
                .lookup_property(&name, PropertyLookupMode::ComponentLocal)
                .internal_or_resolved_name();
            let e = expression_from_reference(NamedReference::new(self, key), &ty, None);
            if let Some(r) = f(&name, e) {
                return Some(r);
            }
        }

        let is_global = match &self.borrow().base_type {
            ElementType::Global => true,
            ElementType::Builtin(b) => b.is_global,
            _ => false,
        };
        if !is_global {
            for (name, ty, visibility) in crate::typeregister::reserved_properties() {
                if visibility == PropertyVisibility::Private {
                    continue;
                }
                let name = SmolStr::new_static(name);
                let e =
                    expression_from_reference(NamedReference::new(self, name.clone()), &ty, None);
                if let Some(r) = f(&name, e) {
                    return Some(r);
                }
            }
        }
        None
    }

    fn lookup(&self, ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        let lookup_result = self.borrow().lookup_property(name, PropertyLookupMode::ComponentLocal);
        if lookup_result.property_type != Type::Invalid
            && (lookup_result.is_local_to_component
                || lookup_result.property_visibility != PropertyVisibility::Private)
        {
            let deprecated = (lookup_result.resolved_name != name.as_str())
                .then(|| format_smolstr!("Please use '{}' instead", lookup_result.resolved_name))
                .or_else(|| {
                    // Only warn about `@deprecated` properties when accessed from outside the
                    // component that declares them
                    lookup_result
                        .deprecated
                        .clone()
                        .filter(|_| !lookup_result.is_local_to_component)
                })
                .or_else(|| check_extra_deprecated(self, ctx, name));
            Some(expression_from_reference(
                NamedReference::new(self, lookup_result.internal_or_resolved_name()),
                &lookup_result.property_type,
                deprecated,
            ))
        } else {
            None
        }
    }
}

/// Returns the deprecation hint message for some hardcoded deprecated properties
pub fn check_extra_deprecated(
    elem: &ElementRc,
    ctx: &LookupCtx<'_>,
    name: &SmolStr,
) -> Option<SmolStr> {
    if crate::typeregister::DEPRECATED_ROTATION_ORIGIN_PROPERTIES.iter().any(|(p, _)| p == name) {
        return Some(format_smolstr!(
            "Please use 'transform-origin.{}' instead",
            &name[name.len() - 1..]
        ));
    }
    let borrow = elem.borrow();
    (!ctx.type_register.expose_internal_types
        && matches!(
            borrow.enclosing_component.upgrade().unwrap().id.as_str(),
            "StyleMetrics" | "NativeStyleMetrics"
        )
        && borrow
            .debug
            .first()
            .and_then(|x| x.node.source_file())
            .is_none_or(|x| x.path().starts_with("builtin:"))
        && !name.starts_with("layout-"))
    .then(|| format_smolstr!("Please use 'Palette.{name}' instead"))
}

fn expression_from_reference(
    n: NamedReference,
    ty: &Type,
    deprecated: Option<SmolStr>,
) -> LookupResult {
    match ty {
        Type::Callback { .. } => Callable::Callback(n).into(),
        Type::InferredCallback => Callable::Callback(n).into(),
        Type::Function(function) => {
            let base_expr = Rc::downgrade(&n.element());
            let callable = Callable::Function(n);
            // If the function has a ElementReference type as the first argument, that usually means it is
            // a member function
            if matches!(function.args.first(), Some(Type::ElementReference)) {
                LookupResult::Callable(LookupResultCallable::MemberFunction {
                    base: Expression::ElementReference(base_expr),
                    source_node: None,
                    member: Box::new(LookupResultCallable::Callable(callable)),
                })
            } else {
                callable.into()
            }
        }
        _ => LookupResult::Expression { expression: Expression::PropertyReference(n), deprecated },
    }
}

/// Lookup for Globals and Enum.
struct LookupType;
impl LookupObject for LookupType {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        for (name, ty) in ctx.type_register.all_types() {
            if let Some(r) = Self::from_type(ty).and_then(|e| f(&name, e)) {
                return Some(r);
            }
        }
        for (name, ty) in ctx.type_register.all_elements() {
            if let Some(r) = Self::from_element(ty, ctx, &name).and_then(|e| f(&name, e)) {
                return Some(r);
            }
        }
        None
    }

    fn lookup(&self, ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        Self::from_type(ctx.type_register.lookup(name))
            .or_else(|| Self::from_element(ctx.type_register.lookup_element(name).ok()?, ctx, name))
    }
}
impl LookupType {
    fn from_type(ty: Type) -> Option<LookupResult> {
        match ty {
            Type::Enumeration(e) => Some(LookupResult::Enumeration(e)),
            _ => None,
        }
    }

    fn from_element(el: ElementType, ctx: &LookupCtx, name: &str) -> Option<LookupResult> {
        match el {
            ElementType::Component(c) if c.is_global() => {
                // Check if it is internal, but allow re-export (different name) eg: NativeStyleMetrics re-exported as StyleMetrics
                if c.root_element
                    .borrow()
                    .builtin_type()
                    .is_some_and(|x| x.is_internal && x.name == name)
                    && !ctx.type_register.expose_internal_types
                {
                    None
                } else {
                    Some(Expression::ElementReference(Rc::downgrade(&c.root_element)).into())
                }
            }
            _ => None,
        }
    }
}

/// Lookup for things specific to the expected type (eg: colors or enums)
pub struct TypeSpecificLookup;
impl LookupObject for TypeSpecificLookup {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let sc = ctx.diag.is_slint_sc();
        match &ctx.expected_type {
            Type::Color | Type::Brush if !sc => ColorSpecific.for_each_entry(ctx, f),
            Type::Easing if !sc => EasingSpecific.for_each_entry(ctx, f),
            Type::MouseCursor if !sc => MouseCursorSpecific.for_each_entry(ctx, f),
            Type::Enumeration(enumeration) => enumeration.clone().for_each_entry(ctx, f),
            _ => None,
        }
    }

    fn lookup(&self, ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        let sc = ctx.diag.is_slint_sc();
        match &ctx.expected_type {
            Type::Color | Type::Brush if !sc => ColorSpecific.lookup(ctx, name),
            Type::Easing if !sc => EasingSpecific.lookup(ctx, name),
            Type::MouseCursor if !sc => MouseCursorSpecific.lookup(ctx, name),
            Type::Enumeration(enumeration) => enumeration.clone().lookup(ctx, name),
            _ => None,
        }
    }
}

struct ColorSpecific;
impl LookupObject for ColorSpecific {
    fn for_each_entry<R>(
        &self,
        _ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        for (name, c) in named_colors().iter() {
            if let Some(r) = f(&SmolStr::new_static(name), Self::as_result(*c)) {
                return Some(r);
            }
        }
        None
    }
    fn lookup(&self, _ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        named_colors().get(name.as_str()).map(|c| Self::as_result(*c))
    }
}
impl ColorSpecific {
    fn as_result(value: u32) -> LookupResult {
        Expression::Cast {
            from: Box::new(Expression::NumberLiteral(value as f64, Unit::None)),
            to: Type::Color,
        }
        .into()
    }
}

/// Given a bare identifier `name` that failed to resolve, return the qualified forms that would
/// resolve it as an enum value or a named color, e.g. `["Colors.red"]` or
/// `["LayoutAlignment.center", "TextHorizontalAlignment.center"]`. This is the reverse of the
/// `ColorSpecific` / enum lookups above, used to build "did you mean" suggestions. The result is
/// sorted and deduplicated so it is deterministic.
pub fn enum_or_color_suggestions(ctx: &LookupCtx, name: &str) -> Vec<SmolStr> {
    let name = crate::parser::normalize_identifier(name);
    let mut result = Vec::new();
    if named_colors().contains_key(name.as_str())
        && BuiltinNamespaceLookup.lookup(ctx, &SmolStr::new_static("Colors")).is_some()
    {
        result.push(smol_str::format_smolstr!("{}.{name}", BuiltinNamespace::Colors));
    }
    for ty in ctx.type_register.all_types().values() {
        if let Type::Enumeration(e) = ty
            && e.lookup(ctx, &name).is_some()
        {
            result.push(smol_str::format_smolstr!("{}.{name}", e.name));
        }
    }
    result.sort();
    result.dedup();
    result
}

pub struct KeysLookup;

macro_rules! special_keys_lookup {
    ($($char:literal # $name:ident # $($shifted:ident)? $(=> $($_muda:ident)? # $($qt:ident)|* # $($winit:ident $(($_pos:ident))?)|* # $($_xkb:ident)|*)? ;)*) => {
        impl LookupObject for KeysLookup {
            fn for_each_entry<R>(
                &self,
                _ctx: &LookupCtx,
                f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
            ) -> Option<R> {
                None
                $(.or_else(|| {
                    let mut tmp = [0; 4];
                    f(&SmolStr::new_static(stringify!($name)), Expression::StringLiteral(SmolStr::new_inline($char.encode_utf8(&mut tmp))).into())
                }))*
            }
        }
    };
}

i_slint_common::for_each_keys!(special_keys_lookup);

struct EasingSpecific;
impl LookupObject for EasingSpecific {
    fn for_each_entry<R>(
        &self,
        _ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        use EasingCurve::CubicBezier;
        let mut curve = |n, e| f(&SmolStr::new_static(n), Expression::EasingCurve(e).into());
        let r = None
            .or_else(|| curve("linear", EasingCurve::Linear))
            .or_else(|| curve("ease-in-quad", CubicBezier(0.11, 0.0, 0.5, 0.0)))
            .or_else(|| curve("ease-out-quad", CubicBezier(0.5, 1.0, 0.89, 1.0)))
            .or_else(|| curve("ease-in-out-quad", CubicBezier(0.45, 0.0, 0.55, 1.0)))
            .or_else(|| curve("ease", CubicBezier(0.25, 0.1, 0.25, 1.0)))
            .or_else(|| curve("ease-in", CubicBezier(0.42, 0.0, 1.0, 1.0)))
            .or_else(|| curve("ease-in-out", CubicBezier(0.42, 0.0, 0.58, 1.0)))
            .or_else(|| curve("ease-out", CubicBezier(0.0, 0.0, 0.58, 1.0)))
            .or_else(|| curve("ease-in-quart", CubicBezier(0.5, 0.0, 0.75, 0.0)))
            .or_else(|| curve("ease-out-quart", CubicBezier(0.25, 1.0, 0.5, 1.0)))
            .or_else(|| curve("ease-in-out-quart", CubicBezier(0.76, 0.0, 0.24, 1.0)))
            .or_else(|| curve("ease-in-quint", CubicBezier(0.64, 0.0, 0.78, 0.0)))
            .or_else(|| curve("ease-out-quint", CubicBezier(0.22, 1.0, 0.36, 1.0)))
            .or_else(|| curve("ease-in-out-quint", CubicBezier(0.83, 0.0, 0.17, 1.0)))
            .or_else(|| curve("ease-in-expo", CubicBezier(0.7, 0.0, 0.84, 0.0)))
            .or_else(|| curve("ease-out-expo", CubicBezier(0.16, 1.0, 0.3, 1.0)))
            .or_else(|| curve("ease-in-out-expo", CubicBezier(0.87, 0.0, 0.13, 1.0)))
            .or_else(|| curve("ease-in-back", CubicBezier(0.36, 0.0, 0.66, -0.56)))
            .or_else(|| curve("ease-out-back", CubicBezier(0.34, 1.56, 0.64, 1.0)))
            .or_else(|| curve("ease-in-out-back", CubicBezier(0.68, -0.6, 0.32, 1.6)))
            .or_else(|| curve("ease-in-sine", CubicBezier(0.12, 0.0, 0.39, 0.0)))
            .or_else(|| curve("ease-out-sine", CubicBezier(0.61, 1.0, 0.88, 1.0)))
            .or_else(|| curve("ease-in-out-sine", CubicBezier(0.37, 0.0, 0.63, 1.0)))
            .or_else(|| curve("ease-in-circ", CubicBezier(0.55, 0.0, 1.0, 0.45)))
            .or_else(|| curve("ease-out-circ", CubicBezier(0.0, 0.55, 0.45, 1.0)))
            .or_else(|| curve("ease-in-out-circ", CubicBezier(0.85, 0.0, 0.15, 1.0)))
            .or_else(|| curve("ease-in-elastic", EasingCurve::EaseInElastic))
            .or_else(|| curve("ease-out-elastic", EasingCurve::EaseOutElastic))
            .or_else(|| curve("ease-in-out-elastic", EasingCurve::EaseInOutElastic))
            .or_else(|| curve("ease-in-bounce", EasingCurve::EaseInBounce))
            .or_else(|| curve("ease-out-bounce", EasingCurve::EaseOutBounce))
            .or_else(|| curve("ease-in-out-bounce", EasingCurve::EaseInOutBounce));
        r.or_else(|| {
            f(&SmolStr::new_static("cubic-bezier"), BuiltinMacroFunction::CubicBezier.into())
        })
        .or_else(|| f(&SmolStr::new_static("spring"), BuiltinMacroFunction::Spring.into()))
    }
}

struct FontWeightLookup;
impl LookupObject for FontWeightLookup {
    fn for_each_entry<R>(
        &self,
        _ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let mut weight =
            |n, v: f64| f(&SmolStr::new_static(n), Expression::NumberLiteral(v, Unit::None).into());
        None.or_else(|| weight("thin", 100.0))
            .or_else(|| weight("extra-light", 200.0))
            .or_else(|| weight("light", 300.0))
            .or_else(|| weight("normal", 400.0))
            .or_else(|| weight("medium", 500.0))
            .or_else(|| weight("semi-bold", 600.0))
            .or_else(|| weight("bold", 700.0))
            .or_else(|| weight("extra-bold", 800.0))
            .or_else(|| weight("black", 900.0))
    }
}

impl LookupObject for Arc<Enumeration> {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        // Builtin enums are not in the Slint SC subset.
        if ctx.diag.is_slint_sc() && self.node.is_none() {
            return None;
        }
        for (value, name) in self.values.iter().enumerate() {
            // Don't offer `auto` in completion for `cross-axis-alignment`, where setting it is an error; `lookup` stays unfiltered.
            if name == "auto"
                && Arc::ptr_eq(self, &crate::typeregister::BUILTIN.enums.CrossAxisAlignment)
                && ctx.property_name == Some("cross-axis-alignment")
            {
                continue;
            }
            if let Some(r) = f(
                name,
                Expression::EnumerationValue(EnumerationValue { value, enumeration: self.clone() })
                    .into(),
            ) {
                return Some(r);
            }
        }
        None
    }

    fn lookup(&self, ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        // Builtin enums are not in the Slint SC subset.
        if ctx.diag.is_slint_sc() && self.node.is_none() {
            return None;
        }
        let value = self.values.iter().position(|v| v == name)?;
        Some(
            Expression::EnumerationValue(EnumerationValue { value, enumeration: self.clone() })
                .into(),
        )
    }
}

struct MathFunctions;
impl LookupObject for MathFunctions {
    fn for_each_entry<R>(
        &self,
        _ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let mut f = |n, e| f(&SmolStr::new_static(n), e);
        let b = |b| LookupResult::from(Callable::Builtin(b));
        None.or_else(|| f("mod", BuiltinMacroFunction::Mod.into()))
            .or_else(|| f("round", b(BuiltinFunction::Round)))
            .or_else(|| f("ceil", b(BuiltinFunction::Ceil)))
            .or_else(|| f("floor", b(BuiltinFunction::Floor)))
            .or_else(|| f("clamp", BuiltinMacroFunction::Clamp.into()))
            .or_else(|| f("abs", BuiltinMacroFunction::Abs.into()))
            .or_else(|| f("sqrt", b(BuiltinFunction::Sqrt)))
            .or_else(|| f("max", BuiltinMacroFunction::Max.into()))
            .or_else(|| f("min", BuiltinMacroFunction::Min.into()))
            .or_else(|| f("sin", b(BuiltinFunction::Sin)))
            .or_else(|| f("cos", b(BuiltinFunction::Cos)))
            .or_else(|| f("tan", b(BuiltinFunction::Tan)))
            .or_else(|| f("asin", b(BuiltinFunction::ASin)))
            .or_else(|| f("acos", b(BuiltinFunction::ACos)))
            .or_else(|| f("atan", b(BuiltinFunction::ATan)))
            .or_else(|| f("atan2", b(BuiltinFunction::ATan2)))
            .or_else(|| f("log", b(BuiltinFunction::Log)))
            .or_else(|| f("ln", b(BuiltinFunction::Ln)))
            .or_else(|| f("pow", b(BuiltinFunction::Pow)))
            .or_else(|| f("exp", b(BuiltinFunction::Exp)))
            .or_else(|| f("sign", BuiltinMacroFunction::Sign.into()))
    }
}

struct MouseCursorSpecific;
impl LookupObject for MouseCursorSpecific {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let e = crate::typeregister::BUILTIN.enums.BuiltInMouseCursor.clone();
        let mut cursor = |n, e| f(n, Expression::MouseCursor(MouseCursorInner::BuiltIn(e)).into());
        let mut r = None;
        for value in &e.values {
            if let Some(enum_value) = e.clone().try_value_from_string(value.as_str()) {
                r = r.or_else(|| cursor(value, Box::new(Expression::EnumerationValue(enum_value))));
            }
        }
        r.or_else(|| {
            // Experimental until the language has enums with data.
            if !ctx.experimental_lookup_enabled() {
                return None;
            }
            f(&SmolStr::new_static("custom"), BuiltinMacroFunction::CustomMouseCursor.into())
        })
    }
}

struct SlintInternal;
impl LookupObject for SlintInternal {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let sl = || ctx.current_token.as_ref().map(|t| t.to_source_location());
        let mut f = |n, e: LookupResult| f(&SmolStr::new_static(n), e);
        let b = |b| LookupResult::from(Callable::Builtin(b));
        None.or_else(|| {
            let style = ctx.type_loader.and_then(|tl| tl.compiler_config.style.as_ref());
            f(
                "color-scheme",
                if style.is_some_and(|s| s.ends_with("-light")) {
                    let e = crate::typeregister::BUILTIN.enums.ColorScheme.clone();
                    Expression::EnumerationValue(e.try_value_from_string("light").unwrap())
                } else if style.is_some_and(|s| s.ends_with("-dark")) {
                    let e = crate::typeregister::BUILTIN.enums.ColorScheme.clone();
                    Expression::EnumerationValue(e.try_value_from_string("dark").unwrap())
                } else {
                    Expression::FunctionCall {
                        function: BuiltinFunction::ColorScheme.into(),
                        arguments: Vec::new(),
                        source_location: sl(),
                    }
                }
                .into(),
            )
        })
        .or_else(|| {
            f(
                "accent-color",
                Expression::FunctionCall {
                    function: BuiltinFunction::AccentColor.into(),
                    arguments: Vec::new(),
                    source_location: sl(),
                }
                .into(),
            )
        })
        .or_else(|| {
            f(
                "use-24-hour-format",
                Expression::FunctionCall {
                    function: BuiltinFunction::Use24HourFormat.into(),
                    arguments: Vec::new(),
                    source_location: sl(),
                }
                .into(),
            )
        })
        .or_else(|| f("month-day-count", b(BuiltinFunction::MonthDayCount)))
        .or_else(|| f("month-offset", b(BuiltinFunction::MonthOffset)))
        .or_else(|| f("format-date", b(BuiltinFunction::FormatDate)))
        .or_else(|| f("date-now", b(BuiltinFunction::DateNow)))
        .or_else(|| f("valid-date", b(BuiltinFunction::ValidDate)))
        .or_else(|| f("parse-date", b(BuiltinFunction::ParseDate)))
    }
}

struct ColorFunctions;
impl LookupObject for ColorFunctions {
    fn for_each_entry<R>(
        &self,
        _ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let mut f = |n, m| f(&SmolStr::new_static(n), LookupResult::from(m));
        None.or_else(|| f("rgb", BuiltinMacroFunction::Rgb))
            .or_else(|| f("rgba", BuiltinMacroFunction::Rgb))
            .or_else(|| f("hsv", BuiltinMacroFunction::Hsv))
            .or_else(|| f("oklch", BuiltinMacroFunction::Oklch))
    }
}

struct BuiltinFunctionLookup;
impl LookupObject for BuiltinFunctionLookup {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        if ctx.diag.is_slint_sc() {
            return None;
        }
        (MathFunctions, ColorFunctions)
            .for_each_entry(ctx, f)
            .or_else(|| f(&SmolStr::new_static("debug"), BuiltinMacroFunction::Debug.into()))
            .or_else(|| {
                f(&SmolStr::new_static("animation-tick"), BuiltinFunction::AnimationTick.into())
            })
    }
}

struct BuiltinNamespaceLookup;
impl LookupObject for BuiltinNamespaceLookup {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        if ctx.diag.is_slint_sc() {
            return None;
        }
        let mut f = |s, res| f(&SmolStr::new_static(s), res);
        None.or_else(|| f("Colors", LookupResult::Namespace(BuiltinNamespace::Colors)))
            .or_else(|| f("Easing", LookupResult::Namespace(BuiltinNamespace::Easing)))
            .or_else(|| f("Math", LookupResult::Namespace(BuiltinNamespace::Math)))
            .or_else(|| f("Key", LookupResult::Namespace(BuiltinNamespace::Key)))
            .or_else(|| f("FontWeight", LookupResult::Namespace(BuiltinNamespace::FontWeight)))
            .or_else(|| {
                if ctx.type_register.expose_internal_types {
                    f("SlintInternal", LookupResult::Namespace(BuiltinNamespace::SlintInternal))
                } else {
                    None
                }
            })
            .or_else(|| f("MouseCursor", LookupResult::Namespace(BuiltinNamespace::MouseCursor)))
    }
}

pub fn global_lookup() -> impl LookupObject {
    (
        LocalVariableLookup,
        (
            ArgumentsLookup,
            (
                SpecialIdLookup,
                (
                    IdLookup,
                    (
                        InScopeLookup,
                        (
                            LookupType,
                            (BuiltinNamespaceLookup, (TypeSpecificLookup, BuiltinFunctionLookup)),
                        ),
                    ),
                ),
            ),
        ),
    )
}

impl LookupObject for Expression {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        match self {
            Expression::ElementReference(e) => e.upgrade().unwrap().for_each_entry(ctx, f),
            _ => match self.ty() {
                Type::Struct(s) => {
                    for name in s.fields.keys() {
                        if let Some(r) = f(
                            name,
                            Expression::StructFieldAccess {
                                base: Box::new(self.clone()),
                                name: name.clone(),
                            }
                            .into(),
                        ) {
                            return Some(r);
                        }
                    }
                    None
                }
                Type::Image => ImageExpression(self).for_each_entry(ctx, f),
                // Only struct fields and image dimensions are members in Slint SC.
                _ if ctx.diag.is_slint_sc() => None,
                Type::String => StringExpression(self).for_each_entry(ctx, f),
                Type::Brush | Type::Color => ColorExpression(self).for_each_entry(ctx, f),
                Type::Array(_) => ArrayExpression(self).for_each_entry(ctx, f),
                Type::Float32 | Type::Int32 | Type::Percent => {
                    NumberExpression(self).for_each_entry(ctx, f)
                }
                Type::Keys => KeysExpression(self).for_each_entry(ctx, f),
                ty if ty.as_unit_product().is_some() => {
                    NumberWithUnitExpression(self).for_each_entry(ctx, f)
                }
                _ => None,
            },
        }
    }

    fn lookup(&self, ctx: &LookupCtx, name: &SmolStr) -> Option<LookupResult> {
        match self {
            Expression::ElementReference(e) => e.upgrade().unwrap().lookup(ctx, name),
            _ => match self.ty() {
                Type::Struct(s) => s.fields.contains_key(name).then(|| {
                    LookupResult::from(Expression::StructFieldAccess {
                        base: Box::new(self.clone()),
                        name: name.clone(),
                    })
                }),
                Type::Image => ImageExpression(self).lookup(ctx, name),
                // Only struct fields and image dimensions are members in Slint SC.
                _ if ctx.diag.is_slint_sc() => None,
                Type::String => StringExpression(self).lookup(ctx, name),
                Type::Brush | Type::Color => ColorExpression(self).lookup(ctx, name),
                Type::Array(_) => ArrayExpression(self).lookup(ctx, name),
                Type::Float32 | Type::Int32 | Type::Percent => {
                    NumberExpression(self).lookup(ctx, name)
                }
                Type::Keys => KeysExpression(self).lookup(ctx, name),
                ty if ty.as_unit_product().is_some() => {
                    NumberWithUnitExpression(self).lookup(ctx, name)
                }
                _ => None,
            },
        }
    }
}

struct StringExpression<'a>(&'a Expression);
impl LookupObject for StringExpression<'_> {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let member_function = builtin_member_function_generator(self.0, ctx);
        let function_call = |f: BuiltinFunction| {
            LookupResult::from(Expression::FunctionCall {
                function: Callable::Builtin(f),
                source_location: ctx.current_token.as_ref().map(|t| t.to_source_location()),
                arguments: vec![self.0.clone()],
            })
        };

        let mut f = |s, res| f(&SmolStr::new_static(s), res);
        None.or_else(|| f("is-float", member_function(BuiltinFunction::StringIsFloat)))
            .or_else(|| f("to-float", member_function(BuiltinFunction::StringToFloat)))
            .or_else(|| f("is-empty", function_call(BuiltinFunction::StringIsEmpty)))
            .or_else(|| f("character-count", function_call(BuiltinFunction::StringCharacterCount)))
            .or_else(|| f("to-lowercase", member_function(BuiltinFunction::StringToLowercase)))
            .or_else(|| f("to-uppercase", member_function(BuiltinFunction::StringToUppercase)))
            .or_else(|| f("starts-with", member_function(BuiltinFunction::StringStartsWith)))
            .or_else(|| f("ends-with", member_function(BuiltinFunction::StringEndsWith)))
            .or_else(|| f("replace-all", member_function(BuiltinFunction::StringReplaceAll)))
    }
}

struct ColorExpression<'a>(&'a Expression);
impl LookupObject for ColorExpression<'_> {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let member_function = |f: BuiltinFunction| {
            let base = if (f == BuiltinFunction::ColorHsvaStruct
                || f == BuiltinFunction::ColorOklchStruct)
                && self.0.ty() == Type::Brush
            {
                Expression::Cast { from: Box::new(self.0.clone()), to: Type::Color }
            } else {
                self.0.clone()
            };
            LookupResult::Callable(LookupResultCallable::MemberFunction {
                base,
                source_node: ctx.current_token.clone(),
                member: Box::new(LookupResultCallable::Callable(Callable::Builtin(f))),
            })
        };
        let field_access = |f: &'static str| {
            let base = if self.0.ty() == Type::Brush {
                Expression::Cast { from: Box::new(self.0.clone()), to: Type::Color }
            } else {
                self.0.clone()
            };
            LookupResult::from(Expression::StructFieldAccess {
                base: Box::new(Expression::FunctionCall {
                    function: BuiltinFunction::ColorRgbaStruct.into(),
                    source_location: ctx.current_token.as_ref().map(|t| t.to_source_location()),
                    arguments: vec![base],
                }),
                name: SmolStr::new_static(f),
            })
        };

        let mut f = |s, res| f(&SmolStr::new_static(s), res);
        None.or_else(|| f("red", field_access("red")))
            .or_else(|| f("green", field_access("green")))
            .or_else(|| f("blue", field_access("blue")))
            .or_else(|| f("alpha", field_access("alpha")))
            .or_else(|| f("to-hsv", member_function(BuiltinFunction::ColorHsvaStruct)))
            .or_else(|| f("to-oklch", member_function(BuiltinFunction::ColorOklchStruct)))
            .or_else(|| f("brighter", member_function(BuiltinFunction::ColorBrighter)))
            .or_else(|| f("darker", member_function(BuiltinFunction::ColorDarker)))
            .or_else(|| f("transparentize", member_function(BuiltinFunction::ColorTransparentize)))
            .or_else(|| f("with-alpha", member_function(BuiltinFunction::ColorWithAlpha)))
            .or_else(|| f("mix", member_function(BuiltinFunction::ColorMix)))
    }
}

struct ImageExpression<'a>(&'a Expression);
impl LookupObject for ImageExpression<'_> {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let field_access = |f: &str| {
            LookupResult::from(Expression::StructFieldAccess {
                base: Box::new(Expression::FunctionCall {
                    function: BuiltinFunction::ImageSize.into(),
                    source_location: ctx.current_token.as_ref().map(|t| t.to_source_location()),
                    arguments: vec![self.0.clone()],
                }),
                name: f.into(),
            })
        };
        let mut f = |s, res| f(&SmolStr::new_static(s), res);
        None.or_else(|| f("width", field_access("width")))
            .or_else(|| f("height", field_access("height")))
    }
}

struct ArrayExpression<'a>(&'a Expression);
impl LookupObject for ArrayExpression<'_> {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let member_function = |f: BuiltinFunction| {
            LookupResult::Callable(LookupResultCallable::MemberFunction {
                base: self.0.clone(),
                source_node: ctx.current_token.clone(),
                member: LookupResultCallable::Callable(Callable::Builtin(f)).into(),
            })
        };
        let function_call = |f: BuiltinFunction| {
            LookupResult::from(Expression::FunctionCall {
                function: Callable::Builtin(f),
                source_location: ctx.current_token.as_ref().map(|t| t.to_source_location()),
                arguments: vec![self.0.clone()],
            })
        };
        let mut member_macro = member_macro_generator(self.0.clone(), ctx.current_token.clone());

        let mut f = |s, res| f(&SmolStr::new_static(s), res);
        None.or_else(|| f("length", function_call(BuiltinFunction::ArrayLength)))
            .or_else(|| f("push", member_macro(BuiltinMacroFunction::ArrayPush)))
            .or_else(|| f("remove", member_macro(BuiltinMacroFunction::ArrayRemove)))
            .or_else(|| f("insert", member_macro(BuiltinMacroFunction::ArrayInsert)))
            .or_else(|| {
                // Experimental: pending optional types for the -1 result, and closures.
                if !ctx.experimental_lookup_enabled() {
                    return None;
                }
                f("index-of", member_macro(BuiltinMacroFunction::ArrayIndexOf))
                    .or_else(|| f("any", member_function(BuiltinFunction::ArrayAny)))
                    .or_else(|| f("all", member_function(BuiltinFunction::ArrayAll)))
                    .or_else(|| f("find-index", member_function(BuiltinFunction::ArrayFindIndex)))
            })
    }
}

/// An expression of type int or float
struct NumberExpression<'a>(&'a Expression);
impl LookupObject for NumberExpression<'_> {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let member_function = builtin_member_function_generator(self.0, ctx);
        let mut member_macro = member_macro_generator(self.0.clone(), ctx.current_token.clone());

        let mut f2 = |s, res| f(&SmolStr::new_static(s), res);
        None.or_else(|| f2("round", member_function(BuiltinFunction::Round)))
            .or_else(|| f2("ceil", member_function(BuiltinFunction::Ceil)))
            .or_else(|| f2("floor", member_function(BuiltinFunction::Floor)))
            .or_else(|| f2("sqrt", member_function(BuiltinFunction::Sqrt)))
            .or_else(|| f2("asin", member_function(BuiltinFunction::ASin)))
            .or_else(|| f2("acos", member_function(BuiltinFunction::ACos)))
            .or_else(|| f2("atan", member_function(BuiltinFunction::ATan)))
            .or_else(|| f2("log", member_function(BuiltinFunction::Log)))
            .or_else(|| f2("ln", member_function(BuiltinFunction::Ln)))
            .or_else(|| f2("pow", member_function(BuiltinFunction::Pow)))
            .or_else(|| f2("exp", member_function(BuiltinFunction::Exp)))
            .or_else(|| f2("sign", member_macro(BuiltinMacroFunction::Sign)))
            .or_else(|| f2("to-fixed", member_function(BuiltinFunction::ToFixed)))
            .or_else(|| f2("to-precision", member_function(BuiltinFunction::ToPrecision)))
            .or_else(|| {
                f2("to-string-unlocalized", member_function(BuiltinFunction::ToStringUnlocalized))
            })
            .or_else(|| NumberWithUnitExpression(self.0).for_each_entry(ctx, f))
    }
}

fn builtin_member_function_generator<'a>(
    base: &'a Expression,
    ctx: &'a LookupCtx,
) -> impl Fn(BuiltinFunction) -> LookupResult {
    move |func: BuiltinFunction| {
        LookupResult::Callable(LookupResultCallable::MemberFunction {
            base: base.clone(),
            source_node: ctx.current_token.clone(),
            member: Box::new(LookupResultCallable::Callable(Callable::Builtin(func))),
        })
    }
}

fn member_macro_generator(
    base: Expression,
    source_node: Option<NodeOrToken>,
) -> impl FnMut(BuiltinMacroFunction) -> LookupResult {
    move |func: BuiltinMacroFunction| {
        LookupResult::Callable(LookupResultCallable::MemberFunction {
            base: base.clone(),
            source_node: source_node.clone(),
            member: Box::new(LookupResultCallable::Macro(func)),
        })
    }
}

/// An expression of any numerical value with an unit
struct NumberWithUnitExpression<'a>(&'a Expression);
impl LookupObject for NumberWithUnitExpression<'_> {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let mut member_macro = member_macro_generator(self.0.clone(), ctx.current_token.clone());
        let member_function = builtin_member_function_generator(self.0, ctx);
        let mut f = |s, res| f(&SmolStr::new_static(s), res);
        None.or_else(|| f("mod", member_macro(BuiltinMacroFunction::Mod)))
            .or_else(|| f("clamp", member_macro(BuiltinMacroFunction::Clamp)))
            .or_else(|| f("abs", member_macro(BuiltinMacroFunction::Abs)))
            .or_else(|| f("max", member_macro(BuiltinMacroFunction::Max)))
            .or_else(|| f("min", member_macro(BuiltinMacroFunction::Min)))
            .or_else(|| {
                if self.0.ty() != Type::Angle {
                    return None;
                }
                None.or_else(|| f("sin", member_function(BuiltinFunction::Sin)))
                    .or_else(|| f("cos", member_function(BuiltinFunction::Cos)))
                    .or_else(|| f("tan", member_function(BuiltinFunction::Tan)))
            })
    }
}

struct KeysExpression<'a>(&'a Expression);

impl LookupObject for KeysExpression<'_> {
    fn for_each_entry<R>(
        &self,
        ctx: &LookupCtx,
        f: &mut impl FnMut(&SmolStr, LookupResult) -> Option<R>,
    ) -> Option<R> {
        let member_function = builtin_member_function_generator(self.0, ctx);
        None.or_else(|| {
            f(&SmolStr::new_static("to-string"), member_function(BuiltinFunction::KeysToString))
        })
    }
}