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use crate::{
Binder1,
BinderN,
Comp,
Pattern,
Val,
Ident,
};
/// A bit of state used to auto-generate fresh variable names.
#[derive(Copy, Debug, Clone, PartialEq, Eq, Hash)]
pub struct IGen(u32);
impl IGen {
pub fn next(&mut self) -> Ident {
let n = Ident::Auto(self.0);
self.0 = self.0 + 1;
n
}
pub fn next_many(&mut self, n: usize) -> Vec<Ident> {
let mut names = Vec::with_capacity(n);
for _ in 0..n {
names.push(self.next());
}
names
}
fn advance(&mut self, x: &Ident) {
match x {
Ident::Manual(_s) => {},
Ident::Auto(n) => {
self.0 = self.0.max(n + 1);
}
}
}
pub fn new() -> Self {
IGen(0)
}
}
impl Binder1 {
fn advance_igen(&self, igen: &mut IGen) {
match self {
Self::Eq(_, vs1, vs2) => {
for v in vs1 {
v.advance_igen(igen);
}
for v in vs2 {
v.advance_igen(igen);
}
}
Self::LogQuantifier(_q, xs, m) => {
for (x,_) in xs {
igen.advance(x);
}
m.advance_igen(igen);
}
Self::QMode(_q, m) => m.advance_igen(igen),
Self::LogOp1(_op, v) => v.advance_igen(igen),
Self::LogOpN(_op, vs) => {
for v in vs {
v.advance_igen(igen);
}
}
}
}
}
impl BinderN {
fn advance_igen(&self, igen: &mut IGen) {
match self {
Self::Call(call) => {
for v in &call.args {
v.advance_igen(igen);
}
}
Self::Seq(m) => {
m.content.advance_igen(igen);
}
}
}
}
impl Comp {
/// Advance the given IGen past any Ident appearing in the
/// computation.
pub fn advance_igen(&self, igen: &mut IGen) {
match self {
Self::Apply(e) => {
e.f.advance_igen(igen);
for v in &e.vals {
v.advance_igen(igen);
}
}
Self::Bind1(b, x, m) => {
b.advance_igen(igen);
igen.advance(&x);
m.advance_igen(igen);
}
Self::BindN(b, ps, m) => {
b.advance_igen(igen);
for p in ps {
p.advance_igen(igen);
}
m.advance_igen(igen);
}
Self::Force(v) => {
v.advance_igen(igen);
}
Self::Fun(xs, m) => {
for (x,_) in xs {
igen.advance(x);
}
m.advance_igen(igen);
}
Self::Ite(cond, then_b, else_b) => {
cond.advance_igen(igen);
then_b.advance_igen(igen);
else_b.advance_igen(igen);
}
Self::Match(v, arms) => {
v.advance_igen(igen);
for (arm, comp) in arms.iter() {
for p in arm.binders.iter() {
p.advance_igen(igen);
}
comp.advance_igen(igen);
}
}
Self::Return(vs) => {
for v in vs {
v.advance_igen(igen);
}
}
}
}
/// Returns an `IGen` that has advanced beyond any `Ident`
/// appearing in the computation.
pub fn get_igen(&self) -> IGen {
let mut igen = IGen::new();
self.advance_igen(&mut igen);
igen
}
}
impl Pattern {
fn advance_igen(&self, igen: &mut IGen) {
match self {
Pattern::NoBind => {}
Pattern::Atom(x) => {
igen.advance(x);
}
Pattern::Tuple(ps) => {
for p in ps {
p.advance_igen(igen);
}
}
}
}
}
impl Val {
fn advance_igen(&self, igen: &mut IGen) {
match self {
Val::Literal(_l) => {},
Val::OpCode(..) => {},
Val::Thunk(m) => m.advance_igen(igen),
Val::Tuple(vs) => {
for v in vs {
v.advance_igen(igen);
}
}
Val::Var(x,_,_,_) => igen.advance(x),
}
}
}