This commit is contained in:
Michael Zhang 2023-11-13 03:08:32 -06:00
parent 327a4e0400
commit 9e14894693
8 changed files with 158 additions and 44 deletions

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@ -18,7 +18,9 @@ pub fn app_ctx(ctx: &Context, ty: &Type) -> Result<Type> {
None => bail!("existential variable {a} doesn't exist in context"),
},
Type::Polytype(a, t) => Ok(Type::Polytype(a.clone(), Box::new(app_ctx(ctx, t)?))),
Type::Polytype(a, t) => {
Ok(Type::Polytype(a.clone(), Box::new(app_ctx(ctx, t)?)))
}
Type::Arrow(a, b) => Ok(Type::Arrow(
Box::new(app_ctx(ctx, a)?),
@ -90,20 +92,30 @@ pub fn subtype(ctx: &Context, left: &Type, right: &Type) -> Result<Context> {
// Figure 10. Instantiation
#[cfg_attr(feature = "trace_execution", trace)]
pub fn instantiate_left(ctx: &Context, a: &str, ty_a: &Type) -> Result<Context> {
pub fn instantiate_left(
ctx: &Context,
a: &str,
ty_a: &Type,
) -> Result<Context> {
match ty_a {
// InstLReach rule
Type::Existential(b) if ctx.has_existential(a) && ctx.has_existential(b) => {
Type::Existential(b)
if ctx.has_existential(a) && ctx.has_existential(b) =>
{
let mut new_ctx = ctx.clone();
{
let b_entry = new_ctx
.0
.iter_mut()
.find(|entry| matches!(entry, ContextEntry::ExistentialVar(x) if x == b))
.find(
|entry| matches!(entry, ContextEntry::ExistentialVar(x) if x == b),
)
.expect("should exist");
*b_entry =
ContextEntry::ExistentialSolved(b.to_owned(), Monotype::Existential(a.to_owned()));
*b_entry = ContextEntry::ExistentialSolved(
b.to_owned(),
Monotype::Existential(a.to_owned()),
);
}
Ok(new_ctx)
@ -119,14 +131,19 @@ pub fn instantiate_left(ctx: &Context, a: &str, ty_a: &Type) -> Result<Context>
}
#[cfg_attr(feature = "trace_execution", trace)]
pub fn instantiate_right(ctx: &Context, ty_a: &Type, a: &str) -> Result<Context> {
pub fn instantiate_right(
ctx: &Context,
ty_a: &Type,
a: &str,
) -> Result<Context> {
match ty_a {
// InstRArr
Type::Arrow(ty_a1, ty_a2) if ctx.has_existential(a) => {
// TODO: In case it's already solved?
println!("original ctx: {ctx:?}");
let (ex_a1_s, ex_a2_s, ctx_gamma_aug) = ctx.split_existential_function(a)?;
let (ex_a1_s, ex_a2_s, ctx_gamma_aug) =
ctx.split_existential_function(a)?;
let ctx_theta = instantiate_left(&ctx_gamma_aug, &ex_a1_s, &ty_a1)?;
@ -148,7 +165,9 @@ pub fn instantiate_right(ctx: &Context, ty_a: &Type, a: &str) -> Result<Context>
let out_ctx = instantiate_right(&aug_ctx, &aug_b, a)?;
let (before, after) = out_ctx
.split_by(|entry| matches!(entry, ContextEntry::Marker(m) if *m == ex_b))
.split_by(
|entry| matches!(entry, ContextEntry::Marker(m) if *m == ex_b),
)
.unwrap();
Ok(before)
@ -259,7 +278,8 @@ pub fn synthesize(ctx: &Context, term: &Term) -> Result<(Type, Context)> {
.unwrap();
info!("Unsolved: {:?}", after_marker.unsolved_existentials());
let mut tau = app_ctx(&after_marker, &Type::Arrow(Box::new(ex_a), Box::new(ex_b)))?;
let mut tau =
app_ctx(&after_marker, &Type::Arrow(Box::new(ex_a), Box::new(ex_b)))?;
for name in after_marker.unsolved_existentials() {
warn!("substituting {tau:?} looking for {name}");
tau = tau.subst(&name, &Type::Var(ex_gen.clone()));
@ -300,7 +320,11 @@ pub fn synthesize(ctx: &Context, term: &Term) -> Result<(Type, Context)> {
}
#[cfg_attr(feature = "trace_execution", trace)]
pub fn app_synthesize(ctx: &Context, fun_ty: &Type, term: &Term) -> Result<(Type, Context)> {
pub fn app_synthesize(
ctx: &Context,
fun_ty: &Type,
term: &Term,
) -> Result<(Type, Context)> {
match (fun_ty, term) {
// →App rule
(Type::Arrow(ty_a, ty_c), e) => {
@ -322,7 +346,8 @@ pub fn app_synthesize(ctx: &Context, fun_ty: &Type, term: &Term) -> Result<(Type
// âApp rule
(Type::Existential(a), e) if ctx.has_existential(a) => {
let (ex_a1_s, ex_a2_s, ctx_gamma_aug) = ctx.split_existential_function(a)?;
let (ex_a1_s, ex_a2_s, ctx_gamma_aug) =
ctx.split_existential_function(a)?;
let ex_a1 = Type::Existential(ex_a1_s.clone());
let ctx_delta = typecheck(&ctx_gamma_aug, e, &ex_a1)?;

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@ -0,0 +1,39 @@
use anyhow::{bail, Result};
use crate::data_debruijn::{Context, Term, Type};
// Figure 8. Applying a context, as a substitution, to a type
pub fn app_ctx(ctx: &Context, ty: &Type) -> Result<Type> {
match ty {
Type::Unit => Ok(Type::Unit),
Type::Var(s) => Ok(Type::Var(s.clone())),
Type::Existential(a) => match ctx.lookup_existential(a) {
Some((_, Some(m))) => Ok(m.into_poly()),
Some((_, None)) => Ok(Type::Existential(a.clone())),
None => bail!("existential variable {a} doesn't exist in context"),
},
Type::Polytype(a, t) => {
Ok(Type::Polytype(a.clone(), Box::new(app_ctx(ctx, t)?)))
}
Type::Arrow(a, b) => Ok(Type::Arrow(
Box::new(app_ctx(ctx, a)?),
Box::new(app_ctx(ctx, b)?),
)),
}
}
pub fn synthesize(ctx: &Context, term: &Term) -> Result<(Type, Context)> {
match term {
// 1I⇒ rule
Term::Unit => Ok((Type::Unit, ctx.clone())),
Term::Var(_) => todo!(),
Term::Lam(_) => todo!(),
Term::App(_, _) => todo!(),
Term::Annot(_, _) => todo!(),
}
}

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@ -2,7 +2,10 @@ use crate::DEPTH;
use crate::{data, data_debruijn, gensym::gensym_type};
pub fn convert_term(term: &data::Term) -> data_debruijn::Term {
fn convert_term_with_context(ctx: &data::Context, term: &data::Term) -> data_debruijn::Term {
fn convert_term_with_context(
ctx: &data::Context,
term: &data::Term,
) -> data_debruijn::Term {
match term {
data::Term::Unit => data_debruijn::Term::Unit,
@ -36,7 +39,10 @@ pub fn convert_term(term: &data::Term) -> data_debruijn::Term {
}
}
fn convert_ty_with_context(ctx: &data::Context, ty: &data::Type) -> data_debruijn::Type {
fn convert_ty_with_context(
ctx: &data::Context,
ty: &data::Type,
) -> data_debruijn::Type {
match ty {
data::Type::Unit => data_debruijn::Type::Unit,

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@ -80,10 +80,15 @@ impl Type {
Type::Unit => HashSet::default(),
Type::Var(x) if ctx.lookup_type(x).is_some() => HashSet::default(),
Type::Var(x) => [FreeVar::Var(x.to_owned())].into_iter().collect(),
Type::Existential(x) if ctx.lookup_existential(x).is_some() => HashSet::default(),
Type::Existential(x) => [FreeVar::Existential(x.to_owned())].into_iter().collect(),
Type::Existential(x) if ctx.lookup_existential(x).is_some() => {
HashSet::default()
}
Type::Existential(x) => {
[FreeVar::Existential(x.to_owned())].into_iter().collect()
}
Type::Polytype(x, ty_a) => {
let new_ctx = ctx.add(vec![ContextEntry::ExistentialVar(x.to_owned())]);
let new_ctx =
ctx.add(vec![ContextEntry::ExistentialVar(x.to_owned())]);
free_vars_with_context(&new_ctx, &ty_a)
}
Type::Arrow(ty_a, ty_b) => {
@ -104,7 +109,9 @@ impl Type {
Type::Var(n) => Type::Var(n.clone()),
Type::Existential(s) if s == var => replacement.clone(),
Type::Existential(s) => Type::Existential(s.clone()),
Type::Polytype(a, t) => Type::Polytype(a.clone(), Box::new(t.subst(var, replacement))),
Type::Polytype(a, t) => {
Type::Polytype(a.clone(), Box::new(t.subst(var, replacement)))
}
Type::Arrow(a, b) => Type::Arrow(
Box::new(a.subst(var, replacement)),
Box::new(b.subst(var, replacement)),
@ -138,7 +145,9 @@ impl Monotype {
Monotype::Unit => Type::Unit,
Monotype::Var(x) => Type::Var(x.clone()),
Monotype::Existential(x) => Type::Existential(x.clone()),
Monotype::Arrow(a, b) => Type::Arrow(Box::new(a.into_poly()), Box::new(b.into_poly())),
Monotype::Arrow(a, b) => {
Type::Arrow(Box::new(a.into_poly()), Box::new(b.into_poly()))
}
}
}
}
@ -202,7 +211,9 @@ impl Context {
.iter()
.enumerate()
.find_map(|(i, entry)| match entry {
ContextEntry::TermAnnot(n, t) if n == name.as_ref() => Some((i, t.clone())),
ContextEntry::TermAnnot(n, t) if n == name.as_ref() => {
Some((i, t.clone()))
}
_ => None,
})
}
@ -216,14 +227,21 @@ impl Context {
/// - Returns Some(Some(t)) if solved
/// - Returns Some(None) if exists but unsolved
/// - Returns None if not found
pub fn lookup_existential(&self, name: impl AsRef<str>) -> Option<(usize, Option<Monotype>)> {
pub fn lookup_existential(
&self,
name: impl AsRef<str>,
) -> Option<(usize, Option<Monotype>)> {
self
.0
.iter()
.enumerate()
.find_map(|(i, entry)| match entry {
ContextEntry::ExistentialVar(n) if n == name.as_ref() => Some((i, None)),
ContextEntry::ExistentialSolved(n, t) if n == name.as_ref() => Some((i, Some(t.clone()))),
ContextEntry::ExistentialVar(n) if n == name.as_ref() => {
Some((i, None))
}
ContextEntry::ExistentialSolved(n, t) if n == name.as_ref() => {
Some((i, Some(t.clone())))
}
_ => None,
})
}
@ -262,14 +280,21 @@ impl Context {
Some((Context(before), Context(after)))
}
pub fn unsplit(left: &Context, center: ContextEntry, right: &Context) -> Context {
pub fn unsplit(
left: &Context,
center: ContextEntry,
right: &Context,
) -> Context {
let mut res = left.clone();
res.0.push_back(center);
res.0.extend(right.0.clone().into_iter());
res
}
pub fn split_existential_function(&self, var: &str) -> Result<(String, String, Context)> {
pub fn split_existential_function(
&self,
var: &str,
) -> Result<(String, String, Context)> {
let mut ctx = self.clone();
let idx = match ctx.lookup_existential(var) {
Some((idx, _)) => idx,

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@ -153,7 +153,9 @@ impl Monotype {
Monotype::Unit => Type::Unit,
Monotype::Var(x) => Type::Var(x.clone()),
Monotype::Existential(x) => Type::Existential(x.clone()),
Monotype::Arrow(a, b) => Type::Arrow(Box::new(a.into_poly()), Box::new(b.into_poly())),
Monotype::Arrow(a, b) => {
Type::Arrow(Box::new(a.into_poly()), Box::new(b.into_poly()))
}
}
}
}
@ -217,7 +219,9 @@ impl Context {
.iter()
.enumerate()
.find_map(|(i, entry)| match entry {
ContextEntry::TermAnnot(n, t) if n == name.as_ref() => Some((i, t.clone())),
ContextEntry::TermAnnot(n, t) if n == name.as_ref() => {
Some((i, t.clone()))
}
_ => None,
})
}
@ -231,14 +235,21 @@ impl Context {
/// - Returns Some(Some(t)) if solved
/// - Returns Some(None) if exists but unsolved
/// - Returns None if not found
pub fn lookup_existential(&self, name: impl AsRef<str>) -> Option<(usize, Option<Monotype>)> {
pub fn lookup_existential(
&self,
name: impl AsRef<str>,
) -> Option<(usize, Option<Monotype>)> {
self
.0
.iter()
.enumerate()
.find_map(|(i, entry)| match entry {
ContextEntry::ExistentialVar(n) if n == name.as_ref() => Some((i, None)),
ContextEntry::ExistentialSolved(n, t) if n == name.as_ref() => Some((i, Some(t.clone()))),
ContextEntry::ExistentialVar(n) if n == name.as_ref() => {
Some((i, None))
}
ContextEntry::ExistentialSolved(n, t) if n == name.as_ref() => {
Some((i, Some(t.clone())))
}
_ => None,
})
}
@ -277,7 +288,11 @@ impl Context {
Some((Context(before), Context(after)))
}
pub fn unsplit(left: &Context, center: ContextEntry, right: &Context) -> Context {
pub fn unsplit(
left: &Context,
center: ContextEntry,
right: &Context,
) -> Context {
let mut res = left.clone();
res.0.push_back(center);
res.0.extend(right.0.clone().into_iter());

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@ -6,13 +6,13 @@ thread_local! {
}
const EXISTENTIALS: [&'static str; 24] = [
"α", "β", "γ", "δ", "ε", "ζ", "η", "θ", "ι", "κ", "λ", "μ", "ν", "ξ", "ο", "π", "ρ", "σ", "τ",
"υ", "φ", "χ", "ψ", "ω",
"α", "β", "γ", "δ", "ε", "ζ", "η", "θ", "ι", "κ", "λ", "μ", "ν", "ξ", "ο",
"π", "ρ", "σ", "τ", "υ", "φ", "χ", "ψ", "ω",
];
const TYPEVARS: [&'static str; 26] = [
"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S",
"T", "U", "V", "W", "X", "Y", "Z",
"A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O",
"P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z",
];
pub fn gensym_existential() -> String {

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@ -1,19 +1,23 @@
use anyhow::{bail, Result};
use crate::{
bidir::{app_ctx, synthesize},
data::{Context, Term},
bidir_debruijn::{app_ctx, synthesize},
convert_data::convert_term,
data_debruijn::Context,
data_debruijn::Term,
parser::TermParser,
};
macro_rules! id_term {
() => {
Term::Lam("x".to_owned(), Box::new(Term::Var("x".to_owned())))
};
fn term_of(str: &'static str) -> Result<Term> {
let term_parser = TermParser::new();
let term = term_parser.parse(str)?;
let converted = convert_term(&term);
Ok(converted)
}
#[test]
fn test_id() -> Result<()> {
let id = id_term!();
let id = term_of(r"\x.x")?;
let ctx = Context::default();
let (ty, out_ctx) = synthesize(&ctx, &id)?;
bail!("Synthesized: {:?} (context = {:?})", ty, out_ctx);
@ -23,8 +27,7 @@ fn test_id() -> Result<()> {
#[test]
fn test_id_of_unit() -> Result<()> {
let id = id_term!();
let id_of_unit = Term::App(Box::new(id), Box::new(Term::Unit));
let id_of_unit = term_of(r"(\x.x) ()")?;
let ctx = Context::default();
let (ty, out_ctx) = synthesize(&ctx, &id_of_unit)?;

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@ -1 +1,2 @@
tab_spaces = 2
max_width = 80