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use super::Typed;
use super::VariableError;
use std::collections::BTreeSet;
use std::fmt::Display;
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct FirstSet {
inner: BTreeSet<char>,
}
impl FirstSet {
pub fn new() -> Self {
Self {
inner: BTreeSet::new(),
}
}
pub fn of_str(s: &str) -> Self {
let mut inner = BTreeSet::new();
s.chars().next().map(|c| inner.insert(c));
Self { inner }
}
pub fn is_empty(&self) -> bool {
self.inner.is_empty()
}
pub fn union(mut self, mut other: Self) -> Self {
self.inner.append(&mut other.inner);
self
}
pub fn intersect(&self, other: &Self) -> Self {
Self {
inner: self.inner.intersection(&other.inner).copied().collect(),
}
}
}
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct FlastSet {
inner: BTreeSet<char>,
}
impl FlastSet {
pub fn new() -> Self {
Self {
inner: BTreeSet::new(),
}
}
pub fn is_empty(&self) -> bool {
self.inner.is_empty()
}
pub fn union_first(mut self, mut other: FirstSet) -> Self {
self.inner.append(&mut other.inner);
self
}
pub fn union(mut self, mut other: Self) -> Self {
self.inner.append(&mut other.inner);
self
}
pub fn intersect_first(&self, other: &FirstSet) -> Self {
Self {
inner: self.inner.intersection(&other.inner).copied().collect(),
}
}
pub fn intersect(&self, other: &Self) -> Self {
Self {
inner: self.inner.intersection(&other.inner).copied().collect(),
}
}
}
pub trait NullContext {
type PushNull: NullContext;
fn get_depth(&self) -> usize;
fn get_nullable(&self, index: usize) -> Option<bool>;
fn push_nullable<F: FnOnce(&mut Self::PushNull) -> R, R>(&mut self, nullable: bool, f: F) -> R;
}
pub trait FirstSetContext: NullContext {
type PushFirstSet: FirstSetContext;
fn get_first_set(&self, index: usize) -> Option<FirstSet>;
fn push_first_set<F: FnOnce(&mut Self::PushFirstSet) -> R, R>(
&mut self,
nullable: bool,
first_set: FirstSet,
f: F,
) -> R;
}
pub trait FlastSetContext: FirstSetContext {
type PushFlastSet: FlastSetContext;
fn get_flast_set(&self, index: usize) -> Option<FlastSet>;
fn push_flast_set<F: FnOnce(&mut Self::PushFlastSet) -> R, R>(
&mut self,
nullable: bool,
first_set: FirstSet,
flast_set: FlastSet,
f: F,
) -> R;
}
pub trait Type {
type Err: Display;
/// # Errors
/// Returns [`Err`] if there is a variable with an index greater than or equal
/// to `depth`.
fn closed(&self, depth: usize) -> Result<(), VariableError>;
/// # Errors
/// Returns [`None`] only if `self.closed(context.get_depth())` returns an
/// [`Err`].
fn is_nullable<C: NullContext>(&self, context: &mut C) -> Option<bool>;
/// # Errors
/// Returns [`None`] only if `self.closed(context.get_depth())` returns an
/// [`Err`].
fn first_set<C: FirstSetContext>(&self, context: &mut C) -> Option<FirstSet>;
/// # Errors
/// Returns [`None`] only if `self.closed(context.get_depth())` returns an
/// [`Err`].
fn flast_set<C: FlastSetContext>(&self, context: &mut C) -> Option<FlastSet>;
/// # Errors
/// Returns an [`Err`] if this term is not well typed.
fn well_typed<C: FlastSetContext>(self, context: &mut C) -> Result<Typed, Self::Err>;
}
|
