use crate::SyntaxKind;
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub(crate) enum FormatBinding {
Operands,
Value,
Results,
Result,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub(crate) enum FormatLiteral {
Colon,
To,
}
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub(crate) enum FormatStep {
Begin(SyntaxKind),
Capture(FormatBinding),
AttributeDictionary,
Literal(FormatLiteral),
Type(FormatBinding),
End(SyntaxKind),
}
#[derive(Clone, Debug, PartialEq, Eq)]
pub(crate) struct OperationFormat {
steps: Box<[FormatStep]>,
}
impl OperationFormat {
pub(crate) fn parse(description: &str) -> Option<Self> {
let directives = scan(description)?;
validate(&directives)?;
Some(Self {
steps: directives.into_boxed_slice(),
})
}
pub(crate) fn steps(&self) -> &[FormatStep] {
&self.steps
}
pub(crate) fn captures(&self, binding: FormatBinding) -> bool {
self.steps.contains(&FormatStep::Capture(binding))
}
pub(crate) fn identity_bytes(&self) -> impl Iterator<Item = u8> + '_ {
self.steps.iter().flat_map(|step| match step {
FormatStep::Begin(kind) => [0, *kind as u8],
FormatStep::Capture(binding) => [1, *binding as u8],
FormatStep::AttributeDictionary => [2, 0],
FormatStep::Literal(literal) => [3, *literal as u8],
FormatStep::Type(binding) => [4, *binding as u8],
FormatStep::End(kind) => [5, *kind as u8],
})
}
}
fn scan(description: &str) -> Option<Vec<FormatStep>> {
let mut raw = Vec::new();
for word in description.split_ascii_whitespace() {
let step = match word {
"$operands" => FormatStep::Capture(FormatBinding::Operands),
"$value" => FormatStep::Capture(FormatBinding::Value),
"attr-dict" => FormatStep::AttributeDictionary,
"`:`" => FormatStep::Literal(FormatLiteral::Colon),
"`to`" => FormatStep::Literal(FormatLiteral::To),
"type($operands)" => FormatStep::Type(FormatBinding::Operands),
"type($value)" => FormatStep::Type(FormatBinding::Value),
"type($results)" => FormatStep::Type(FormatBinding::Results),
"type($result)" => FormatStep::Type(FormatBinding::Result),
_ => return None,
};
raw.push(step);
}
let operand_program = raw.contains(&FormatStep::Capture(FormatBinding::Operands));
let mut steps = Vec::with_capacity(raw.len() + 4);
for step in raw {
if step == FormatStep::Capture(FormatBinding::Value) {
steps.push(FormatStep::Begin(SyntaxKind::ArithConstantValue));
}
if step == FormatStep::Type(FormatBinding::Operands) {
steps.push(FormatStep::Begin(SyntaxKind::FunctionType));
}
if !operand_program && step == FormatStep::Type(FormatBinding::Result) {
steps.push(FormatStep::Begin(SyntaxKind::FunctionType));
}
steps.push(step);
if step == FormatStep::Type(FormatBinding::Value) {
steps.push(FormatStep::End(SyntaxKind::ArithConstantValue));
}
if matches!(
step,
FormatStep::Type(FormatBinding::Results | FormatBinding::Result)
) && steps.contains(&FormatStep::Begin(SyntaxKind::FunctionType))
{
steps.push(FormatStep::End(SyntaxKind::FunctionType));
}
}
Some(steps)
}
fn validate(steps: &[FormatStep]) -> Option<()> {
let directive_count = steps
.iter()
.filter(|step| !matches!(step, FormatStep::Begin(_) | FormatStep::End(_)))
.count();
if directive_count != 6 {
return None;
}
let operand_capture = steps
.iter()
.position(|step| *step == FormatStep::Capture(FormatBinding::Operands));
let value_capture = steps
.iter()
.position(|step| *step == FormatStep::Capture(FormatBinding::Value));
if operand_capture.is_some() == value_capture.is_some() {
return None;
}
if steps
.iter()
.filter(|step| matches!(step, FormatStep::AttributeDictionary))
.count()
!= 1
{
return None;
}
if let Some(capture) = operand_capture {
let attributes = position(steps, FormatStep::AttributeDictionary)?;
let operand_type = position(steps, FormatStep::Type(FormatBinding::Operands))?;
let result_type = position(steps, FormatStep::Type(FormatBinding::Results))?;
let colon = position(steps, FormatStep::Literal(FormatLiteral::Colon))?;
let to = position(steps, FormatStep::Literal(FormatLiteral::To))?;
(capture < attributes
&& attributes < colon
&& colon < operand_type
&& operand_type < to
&& to < result_type)
.then_some(())
} else {
let capture = value_capture?;
let attributes = position(steps, FormatStep::AttributeDictionary)?;
let value_type = position(steps, FormatStep::Type(FormatBinding::Value))?;
let result_type = position(steps, FormatStep::Type(FormatBinding::Result))?;
let colons = steps
.iter()
.enumerate()
.filter_map(|(index, step)| {
(*step == FormatStep::Literal(FormatLiteral::Colon)).then_some(index)
})
.collect::<Vec<_>>();
(colons.len() == 2
&& capture < colons[0]
&& colons[0] < value_type
&& value_type < attributes
&& attributes < colons[1]
&& colons[1] < result_type)
.then_some(())
}
}
fn position(steps: &[FormatStep], needle: FormatStep) -> Option<usize> {
let mut positions = steps
.iter()
.enumerate()
.filter_map(|(index, step)| (*step == needle).then_some(index));
let position = positions.next()?;
positions.next().is_none().then_some(position)
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn compiles_supported_formats_and_rejects_invalid_bindings() {
assert!(
OperationFormat::parse("$operands attr-dict `:` type($operands) `to` type($results)")
.is_some()
);
assert!(
OperationFormat::parse("$value `:` type($value) attr-dict `:` type($result)").is_some()
);
assert!(OperationFormat::parse("$value `:` type($operands)").is_none());
assert!(OperationFormat::parse("$operands `to` type($results)").is_none());
}
}