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use crate::{
Binder1,
BinderN,
Comp,
Pattern,
Val,
VName,
};
/// A bit of state used to auto-generate fresh variable names.
#[derive(Copy, Debug, Clone, PartialEq, Eq, Hash)]
pub struct Gen(u32);
impl Gen {
pub fn next(&mut self) -> VName {
let n = VName::Auto(self.0);
self.0 = self.0 + 1;
n
}
pub fn next_many(&mut self, n: usize) -> Vec<VName> {
let mut names = Vec::with_capacity(n);
for _ in 0..n {
names.push(self.next());
}
names
}
fn advance(&mut self, x: &VName) {
match x {
VName::Manual(_s) => {},
VName::Auto(n) => {
self.0 = self.0.max(n + 1);
}
}
}
pub fn new() -> Self {
Gen(0)
}
}
impl Binder1 {
fn advance_gen(&self, gen: &mut Gen) {
match self {
Self::Eq(_, vs1, vs2) => {
for v in vs1 {
v.advance_gen(gen);
}
for v in vs2 {
v.advance_gen(gen);
}
}
Self::LogQuantifier(_q, xs, m) => {
for (x,_) in xs {
gen.advance(x);
}
m.advance_gen(gen);
}
Self::LogNot(v) => v.advance_gen(gen),
Self::LogOpN(_op, vs) => {
for v in vs {
v.advance_gen(gen);
}
}
}
}
}
impl BinderN {
fn advance_gen(&self, gen: &mut Gen) {
match self {
Self::Call(_oc, _vs) => todo!(),
Self::Seq(m) => {
m.advance_gen(gen);
}
}
}
}
impl Comp {
/// Advance the given Gen past any VName appearing in the
/// computation.
pub fn advance_gen(&self, gen: &mut Gen) {
match self {
Self::Apply(m,_,vs) => {
m.advance_gen(gen);
for v in vs {
v.advance_gen(gen);
}
}
Self::Bind1(b, x, m) => {
b.advance_gen(gen);
gen.advance(&x);
m.advance_gen(gen);
}
Self::BindN(b, ps, m) => {
b.advance_gen(gen);
for p in ps {
p.advance_gen(gen);
}
m.advance_gen(gen);
}
Self::Force(v) => {
v.advance_gen(gen);
}
Self::Fun(xs, m) => {
for (x,_) in xs {
gen.advance(x);
}
m.advance_gen(gen);
}
Self::Ite(cond, then_b, else_b) => {
cond.advance_gen(gen);
then_b.advance_gen(gen);
else_b.advance_gen(gen);
}
Self::Return(vs) => {
for v in vs {
v.advance_gen(gen);
}
}
}
}
/// Returns a Gen that has advanced beyond any VName
/// appearing in the computation.
pub fn get_gen(&self) -> Gen {
let mut gen = Gen::new();
self.advance_gen(&mut gen);
gen
}
}
impl Pattern {
fn advance_gen(&self, gen: &mut Gen) {
match self {
Pattern::NoBind => {}
Pattern::Atom(x) => {
gen.advance(x);
}
Pattern::Tuple(ps) => {
for p in ps {
p.advance_gen(gen);
}
}
}
}
}
impl Val {
fn advance_gen(&self, gen: &mut Gen) {
match self {
Val::Literal(_l) => {},
Val::OpCode(..) => {},
Val::Thunk(m) => m.advance_gen(gen),
Val::Tuple(vs) => {
for v in vs {
v.advance_gen(gen);
}
}
Val::Var(x,_) => gen.advance(x),
}
}
}