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use super::*;
pub(crate) enum NativeRead {
Outer(usize),
Subject,
Local(usize),
}
pub(crate) enum NativeOuter<'a, V> {
Slots(&'a [&'a V]),
Bindings {
values: &'a Bindings<V>,
names: &'a [String],
},
}
impl<V> NativeOuter<'_, V> {
fn get(&self, index: usize, range: &Range<usize>) -> Result<&V, QueryError> {
match self {
Self::Slots(values) => Ok(values[index]),
Self::Bindings { values, names } => values.get(&names[index], range.clone()),
}
}
}
pub(crate) enum PreparedNative {
Input,
Binding(NativeRead),
Group(Box<Self>),
Field(Box<Self>),
Sequence {
input: Box<Self>,
arguments: Vec<Vec<usize>>,
},
Set {
left: Box<Self>,
rights: Vec<Self>,
},
}
impl PreparedNative {
pub fn resolve<C, H: ProjectionHost<C>>(
expression: &NativeExpression<C, H>,
host: &H,
outer: &[&str],
subject: Option<&str>,
locals: &[(&str, Vec<ValueType>)],
budget: &mut Budget,
) -> Result<Self, QueryError> {
budget.within_evaluation(
expression.value.depth(),
Location::Query(expression.range.clone()),
|budget| {
budget.charge(1, Location::Query(expression.range.clone()))?;
Ok(match &expression.value {
ExpressionKind::Input => Self::Input,
ExpressionKind::Binding(name) => {
let work = outer
.iter()
.copied()
.chain(locals.iter().map(|(name, _)| *name))
.try_fold(0usize, |work, local| {
work.checked_add(1 + local.len().min(name.len()))
.ok_or_else(|| {
QueryError::query(
expression.range.clone(),
"native resolution metadata overflow",
)
})
})?;
budget.charge(work, Location::Query(expression.range.clone()))?;
Self::Binding(
if let Some(index) =
locals.iter().rposition(|(local, _)| *local == name)
{
NativeRead::Local(index)
} else if subject == Some(name.as_str()) {
NativeRead::Subject
} else {
NativeRead::Outer(
outer.iter().position(|outer| *outer == name).ok_or_else(
|| {
QueryError::query(
expression.range.clone(),
format!("undefined binding: {name}"),
)
},
)?,
)
},
)
}
ExpressionKind::Group(value) => Self::Group(Box::new(Self::resolve::<C, H>(
value, host, outer, subject, locals, budget,
)?)),
ExpressionKind::Field { value, .. } => {
Self::Field(Box::new(Self::resolve::<C, H>(
value, host, outer, subject, locals, budget,
)?))
}
ExpressionKind::Sequence { input, steps } => {
admit_slots::<Vec<usize>>(steps.len(), budget, &expression.range)?;
let mut arguments = Vec::with_capacity(steps.len());
for step in steps {
let ExpressionStep::Stage(stage) = &step.value else {
unreachable!("pure native stage preflight")
};
let declared = host.value_arguments(stage, budget, &step.range)?;
admit_slots::<usize>(declared.len(), budget, &step.range)?;
arguments.push(
declared
.into_iter()
.map(|(expression, _)| expression as *const _ as usize)
.collect(),
);
}
Self::Sequence {
input: Box::new(Self::resolve::<C, H>(
input, host, outer, subject, locals, budget,
)?),
arguments,
}
}
ExpressionKind::Set { .. } => {
let mut rights = Vec::new();
let mut operand = expression;
while let ExpressionKind::Set { left, right, .. } = &operand.value {
admit_slots::<Self>(1, budget, &operand.range)?;
rights.push(Self::resolve::<C, H>(
right, host, outer, subject, locals, budget,
)?);
operand = left;
}
Self::Set {
left: Box::new(Self::resolve::<C, H>(
operand, host, outer, subject, locals, budget,
)?),
rights,
}
}
ExpressionKind::Record(_) => {
return Err(QueryError::query(
expression.range.clone(),
"native records require explicit scalar field projections",
));
}
})
},
)
}
#[expect(
clippy::too_many_arguments,
reason = "Prepared native operands retain explicit context and lexical slots"
)]
pub fn run<C, H: ProjectionHost<C>>(
&self,
expression: &NativeExpression<C, H>,
host: &H,
input: H::Value,
context: &mut C,
bindings: &Bindings<H::Value>,
outer: &[&H::Value],
subject: &H::Value,
locals: &[&H::Value],
arguments: &mut dyn crate::ValueArguments<NativeExpression<C, H>, EvaluationError<H::Error>>,
native: &BTreeMap<usize, Self>,
scope: &BTreeMap<String, H::Kind>,
budget: &mut Budget,
) -> Result<H::Value, EvaluationError<H::Error>> {
self.execute(
expression,
host,
Some(input),
context,
bindings,
&NativeOuter::Slots(outer),
Some(subject),
locals,
&mut |stage, declared, value, context, bindings, budget, range| {
let mut arguments = StageArguments {
host,
context,
bindings,
scope,
prepared: native,
declared,
values: arguments,
};
host.evaluate_stage_with_arguments(stage, value, &mut arguments, budget, range)
},
budget,
)
}
#[expect(
clippy::too_many_arguments,
reason = "One native traversal serves ordinary projections and function callbacks"
)]
pub(crate) fn execute<C, H: ProjectionHost<C>>(
&self,
expression: &NativeExpression<C, H>,
host: &H,
input: Option<H::Value>,
context: &mut C,
bindings: &Bindings<H::Value>,
outer: &NativeOuter<'_, H::Value>,
subject: Option<&H::Value>,
locals: &[&H::Value],
run_stage: &mut impl FnMut(
&H::Stage,
&[usize],
H::Value,
&mut C,
&Bindings<H::Value>,
&mut Budget,
&Range<usize>,
) -> Result<H::Value, EvaluationError<H::Error>>,
budget: &mut Budget,
) -> Result<H::Value, EvaluationError<H::Error>> {
budget.within_evaluation(
expression.value.depth(),
Location::Query(expression.range.clone()),
|budget| {
budget.charge_program_work(1, Location::Query(expression.range.clone()))?;
match (self, &expression.value) {
(Self::Input, ExpressionKind::Input) => input.ok_or_else(|| {
QueryError::query(
expression.range.clone(),
"native input requires an explicit argument input",
)
.into()
}),
(Self::Binding(read), ExpressionKind::Binding(_)) => {
let value = match *read {
NativeRead::Outer(index) => outer.get(index, &expression.range)?,
NativeRead::Subject => subject.expect("prepared subject"),
NativeRead::Local(index) => locals[index],
};
host.copy_value(value, context, budget, &expression.range)
}
(Self::Group(prepared), ExpressionKind::Group(value)) => prepared.execute(
value, host, input, context, bindings, outer, subject, locals, run_stage,
budget,
),
(Self::Field(prepared), ExpressionKind::Field { value, field }) => {
let value = prepared.execute(
value, host, input, context, bindings, outer, subject, locals,
run_stage, budget,
)?;
let record = host.capture_record(&value).ok_or_else(|| {
QueryError::query(
field.range.clone(),
"field access requires a native capture",
)
})?;
host.copy_value(record.get(field, budget)?, context, budget, &field.range)
}
(
Self::Sequence {
input: prepared,
arguments: declared,
},
ExpressionKind::Sequence {
input: source,
steps,
},
) => {
let explicit = matches!(source.value, ExpressionKind::Input)
&& steps.first().is_some_and(|step| match &step.value {
ExpressionStep::Stage(stage) => host.is_explicit_source(stage),
ExpressionStep::Emit { .. } => false,
});
let mut value = if explicit {
budget.charge_results(1, Location::Query(expression.range.clone()))?;
host.lift_constructed(
crate::ConstructedValue::Absent,
vec![crate::ValueType::Absent],
context,
budget,
&expression.range,
)?
} else {
prepared.execute(
source, host, input, context, bindings, outer, subject, locals,
run_stage, budget,
)?
};
for (step, declared) in steps.iter().zip(declared) {
let ExpressionStep::Stage(stage) = &step.value else {
unreachable!("prepared native query is pure")
};
value = run_stage(
stage,
declared,
value,
context,
bindings,
budget,
&step.range,
)?;
}
Ok(value)
}
(Self::Set { left, rights }, ExpressionKind::Set { .. }) => {
let mut pending = Vec::new();
let mut operand = expression;
let mut input = input;
for prepared in rights {
let ExpressionKind::Set {
operator,
left,
right,
} = &operand.value
else {
unreachable!("prepared set shape")
};
if !pending.is_empty() {
budget.charge_program_work(
1,
Location::Query(operand.range.clone()),
)?;
}
admit_slots::<(
&H::SetOperator,
&NativeExpression<C, H>,
Option<H::Value>,
&Range<usize>,
&Self,
)>(1, budget, &operand.range)?;
let left_input = input
.as_ref()
.map(|input| host.copy_value(input, context, budget, &left.range))
.transpose()?;
pending.push((operator, right, input, &operand.range, prepared));
operand = left;
input = left_input;
}
let mut value = left.execute(
operand, host, input, context, bindings, outer, subject, locals,
run_stage, budget,
)?;
while let Some((operator, right, input, range, prepared)) = pending.pop() {
let right = prepared.execute(
right, host, input, context, bindings, outer, subject, locals,
run_stage, budget,
)?;
value = host.combine(operator, value, right, context, budget, range)?;
}
Ok(value)
}
_ => unreachable!("prepared native expression matches its borrowed source"),
}
},
)
}
}