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|
use proc_macro2::Span;
use super::Typed;
use super::VariableError;
use std::collections::BTreeSet;
use std::fmt::Display;
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
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(),
}
}
}
impl IntoIterator for FirstSet {
type Item = char;
type IntoIter = <BTreeSet<char> as IntoIterator>::IntoIter;
fn into_iter(self) -> Self::IntoIter {
self.inner.into_iter()
}
}
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
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(),
}
}
}
#[derive(Debug)]
pub struct NullContext<'a> {
inner: &'a mut FlastContext
}
impl NullContext<'_> {
pub fn depth(&self) -> usize {
self.inner.depth()
}
pub fn is_guarded(&self, index: usize) -> Option<bool> {
self.inner.is_guarded(index)
}
pub fn unguard<F: FnOnce(&mut NullContext<'_>) -> R, R>(&mut self, f: F) -> R {
self.inner.unguard(|ctx| f(&mut NullContext {inner: ctx}))
}
pub fn is_nullable(&self, index: usize) -> Option<bool> {
self.inner.is_nullable(index)
}
pub fn push_nullable<F: FnOnce(&mut NullContext<'_>) -> R, R>(
&mut self,
nullable: bool,
f: F,
) -> R {
self.inner.push_nullable(nullable, f)
}
}
#[derive(Debug)]
pub struct FirstContext<'a> {
inner: &'a mut FlastContext,
}
impl FirstContext<'_> {
pub fn depth(&self) -> usize {
self.inner.depth()
}
pub fn is_guarded(&self, index: usize) -> Option<bool> {
self.inner.is_guarded(index)
}
pub fn unguard<F: FnOnce(&mut FirstContext<'_>) -> R, R>(&mut self, f: F) -> R {
self.inner.unguard(|ctx| {
f(&mut FirstContext{inner: ctx})
})
}
pub fn is_nullable(&self, index: usize) -> Option<bool> {
self.inner.is_nullable(index)
}
pub fn push_nullable<F: FnOnce(&mut NullContext<'_>) -> R, R>(
&mut self,
nullable: bool,
f: F,
) -> R {
self.inner.push_nullable(nullable, f)
}
pub fn first_set(&self, index: usize) -> Option<&FirstSet> {
self.inner.first_set(index)
}
pub fn push_first_set<F: FnOnce(&mut FirstContext<'_>) -> R, R>(
&mut self,
nullable: bool,
first_set: FirstSet,
f: F,
) -> R {
self.inner.push_first_set(nullable, first_set, f)
}
pub fn as_null(&mut self) -> NullContext<'_> {
NullContext {
inner: self.inner
}
}
}
#[derive(Debug)]
pub struct FlastContext {
data: Vec<(bool, FirstSet, FlastSet)>,
guard: Vec<usize>,
}
impl FlastContext {
pub fn new() -> Self {
Self {
data: Vec::new(),
guard: Vec::new(),
}
}
pub fn depth(&self) -> usize {
self.data.len()
}
pub fn is_guarded(&self, index: usize) -> Option<bool> {
if self.data.len() <= index {
None
} else if self.guard.is_empty() {
Some(false)
} else {
Some(self.guard[self.guard.len() - 1] + index >= self.data.len())
}
}
pub fn unguard<F: FnOnce(&mut Self) -> R, R>(&mut self, f: F) -> R {
self.guard.push(self.data.len());
let res = f(self);
self.guard.pop();
res
}
pub fn is_nullable(&self, index: usize) -> Option<bool> {
self.data.get(index).map(|(null, _, _)| *null)
}
pub fn push_nullable<F: FnOnce(&mut NullContext<'_>) -> R, R>(
&mut self,
nullable: bool,
f: F,
) -> R {
self.push_first_set(nullable, FirstSet::new(), |ctx| {
f(&mut ctx.as_null())
})
}
pub fn first_set(&self, index: usize) -> Option<&FirstSet> {
self.data.get(index).map(|(_, first, _)| first)
}
pub fn push_first_set<F: FnOnce(&mut FirstContext<'_>) -> R, R>(
&mut self,
nullable: bool,
first_set: FirstSet,
f: F,
) -> R {
self.push_flast_set(nullable, first_set, FlastSet::new(), |ctx| f(&mut ctx.as_first()))
}
pub fn flast_set(&self, index: usize) -> Option<&FlastSet> {
self.data.get(index).map(|(_, _, flast)| flast)
}
pub fn push_flast_set<F: FnOnce(&mut Self) -> R, R>(
&mut self,
nullable: bool,
first_set: FirstSet,
flast_set: FlastSet,
f: F,
) -> R {
self.data.push((nullable, first_set, flast_set));
let res = f(self);
self.data.pop();
res
}
pub fn as_first(&mut self) -> FirstContext<'_> {
FirstContext {
inner: self
}
}
pub fn as_null(&mut self) -> NullContext<'_> {
NullContext{
inner: self
}
}
}
pub trait Type {
type Err: Into<syn::Error>;
/// # 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(&self, context: &mut NullContext<'_>) -> Option<bool>;
/// # Errors
/// Returns [`None`] only if `self.closed(context.get_depth())` returns an
/// [`Err`].
fn first_set(&self, context: &mut FirstContext<'_>) -> Option<FirstSet>;
/// # Errors
/// Returns [`None`] only if `self.closed(context.get_depth())` returns an
/// [`Err`].
fn flast_set(&self, context: &mut FlastContext) -> Option<FlastSet>;
/// # Errors
/// Returns an [`Err`] if this term is not well typed.
fn well_typed(self, context: &mut FlastContext) -> Result<(Typed, Span), Self::Err>;
}
|
