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-rw-r--r--dhall/src/semantics/core/value.rs118
-rw-r--r--dhall/src/semantics/nze/nzexpr.rs34
-rw-r--r--dhall/src/semantics/tck/tyexpr.rs15
-rw-r--r--dhall/src/tests.rs18
4 files changed, 68 insertions, 117 deletions
diff --git a/dhall/src/semantics/core/value.rs b/dhall/src/semantics/core/value.rs
index 35913cf..42da653 100644
--- a/dhall/src/semantics/core/value.rs
+++ b/dhall/src/semantics/core/value.rs
@@ -303,7 +303,9 @@ impl Value {
} => TyExprKind::Expr(ExprKind::Lam(
binder.to_label(),
annot.to_tyexpr(qenv),
- closure.normalize().to_tyexpr(qenv.insert()),
+ closure
+ .apply_var(NzVar::new(qenv.size()))
+ .to_tyexpr(qenv.insert()),
)),
ValueKind::PiClosure {
binder,
@@ -312,7 +314,9 @@ impl Value {
} => TyExprKind::Expr(ExprKind::Pi(
binder.to_label(),
annot.to_tyexpr(qenv),
- closure.normalize().to_tyexpr(qenv.insert()),
+ closure
+ .apply_var(NzVar::new(qenv.size()))
+ .to_tyexpr(qenv.insert()),
)),
ValueKind::AppliedBuiltin(b, args, types) => {
TyExprKind::Expr(args.into_iter().zip(types.into_iter()).fold(
@@ -692,120 +696,17 @@ impl Closure {
pub fn apply(&self, val: Value) -> Value {
self.body.normalize_whnf(&self.env.insert_value(val))
}
- pub fn apply_fresh(&self, env: QuoteEnv) -> Value {
+ pub fn apply_var(&self, var: NzVar) -> Value {
let val = Value::from_kind_and_type(
- ValueKind::Var(AlphaVar::default(), NzVar::new(env.size())),
+ ValueKind::Var(AlphaVar::default(), var),
self.arg_ty.clone(),
);
self.apply(val)
}
- pub fn normalize(&self) -> Value {
- self.body
- .normalize_whnf(&self.env.insert_type(self.arg_ty.clone()))
- }
}
/// Compare two values for equality modulo alpha/beta-equivalence.
// TODO: use Rc comparison to shortcut on identical pointers
-fn equiv(val1: &Value, val2: &Value) -> bool {
- struct ValueWithEnv<'v> {
- val: &'v Value,
- env: QuoteEnv,
- }
- impl<'v> PartialEq for ValueWithEnv<'v> {
- fn eq(&self, other: &ValueWithEnv<'v>) -> bool {
- equiv_with_env(self.env, self.val, other.env, other.val)
- }
- }
- // Push the given context into every subnode of the ValueKind. That way, normal equality of the
- // resulting value will take into account the context.
- fn push_context<'v>(
- env: QuoteEnv,
- kind: &'v ValueKind<Value>,
- ) -> ValueKind<ValueWithEnv<'v>> {
- kind.map_ref_with_special_handling_of_binders(
- |val| ValueWithEnv { val, env },
- |_, _, val| ValueWithEnv {
- val,
- env: env.insert(),
- },
- )
- }
-
- fn equiv_with_env<'v>(
- env1: QuoteEnv,
- val1: &'v Value,
- env2: QuoteEnv,
- val2: &'v Value,
- ) -> bool {
- use ValueKind::Var;
- let kind1 = val1.as_whnf();
- let kind2 = val2.as_whnf();
- match (&*kind1, &*kind2) {
- (Var(_, v1), Var(_, v2)) => {
- v1 == v2
- // match (env1.lookup(v1), env2.lookup(v2)) {
- // // Both vars were found in the environment, check they point to the same
- // // binder.
- // // Does that even make any sense with an incomplete environment ?
- // // I have no clue what I'm doing anymore.
- // (Some(i), Some(j)) => i == j,
- // // Both vars point to outside the environment ????
- // // (None, None) => v1 == v2,
- // _ => false,
- // }
- }
- // (Var(_, v1), Var(_, v2)) => env1.lookup(v1) == env2.lookup(v2),
- (
- ValueKind::LamClosure {
- annot: a1,
- closure: cl1,
- ..
- },
- ValueKind::LamClosure {
- annot: a2,
- closure: cl2,
- ..
- },
- ) => {
- equiv_with_env(env1, a1, env2, a2)
- && equiv_with_env(
- env1.insert(),
- &cl1.apply_fresh(env1),
- env2.insert(),
- &cl2.apply_fresh(env2),
- )
- }
- (
- ValueKind::PiClosure {
- annot: a1,
- closure: cl1,
- ..
- },
- ValueKind::PiClosure {
- annot: a2,
- closure: cl2,
- ..
- },
- ) => {
- equiv_with_env(env1, a1, env2, a2)
- && equiv_with_env(
- env1.insert(),
- &cl1.apply_fresh(env1),
- env2.insert(),
- &cl2.apply_fresh(env2),
- )
- }
- (k1, k2) => push_context(env1, k1) == push_context(env2, k2),
- }
- }
-
- // TODO: need to use ambiant env instead of creating new one
- // Might be possible to generate free variables differently to avoid this
- equiv_with_env(QuoteEnv::new(), val1, QuoteEnv::new(), val2)
-}
-
-// TODO: use Rc comparison to shortcut on identical pointers
impl std::cmp::PartialEq for Value {
fn eq(&self, other: &Self) -> bool {
*self.as_whnf() == *other.as_whnf()
@@ -815,7 +716,8 @@ impl std::cmp::Eq for Value {}
impl std::cmp::PartialEq for Closure {
fn eq(&self, other: &Self) -> bool {
- self.normalize() == other.normalize()
+ let v = NzVar::fresh();
+ self.apply_var(v) == other.apply_var(v)
}
}
impl std::cmp::Eq for Closure {}
diff --git a/dhall/src/semantics/nze/nzexpr.rs b/dhall/src/semantics/nze/nzexpr.rs
index 33fdde3..6559082 100644
--- a/dhall/src/semantics/nze/nzexpr.rs
+++ b/dhall/src/semantics/nze/nzexpr.rs
@@ -81,10 +81,12 @@ pub(crate) struct QuoteEnv {
size: usize,
}
-// Reverse-debruijn index: counts number of binders from the bottom of the stack.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub(crate) struct NzVar {
- idx: usize,
+pub(crate) enum NzVar {
+ /// Reverse-debruijn index: counts number of binders from the bottom of the stack.
+ Bound(usize),
+ /// Fake fresh variable generated for expression equality checking.
+ Fresh(usize),
}
// TODO: temporary hopefully
// impl std::cmp::PartialEq for NzVar {
@@ -207,7 +209,9 @@ impl NzEnv {
let idx = self.items.len() - 1 - var.idx();
match &self.items[idx] {
NzEnvItem::Kept(ty) => NzExpr::new(
- NzExprKind::Var { var: NzVar { idx } },
+ NzExprKind::Var {
+ var: NzVar::new(idx),
+ },
Some(ty.clone()),
),
NzEnvItem::Replaced(x) => x.clone(),
@@ -235,18 +239,32 @@ impl QuoteEnv {
self.lookup_fallible(var).unwrap()
}
pub fn lookup_fallible(&self, var: &NzVar) -> Option<AlphaVar> {
- let idx = self.size.checked_sub(var.idx + 1)?;
+ let idx = self.size.checked_sub(var.idx() + 1)?;
Some(AlphaVar::new(V((), idx)))
}
}
impl NzVar {
pub fn new(idx: usize) -> Self {
- NzVar { idx }
+ NzVar::Bound(idx)
+ }
+ pub fn fresh() -> Self {
+ use std::sync::atomic::{AtomicUsize, Ordering};
+ // Global counter to ensure uniqueness of the generated id.
+ static FRESH_VAR_COUNTER: AtomicUsize = AtomicUsize::new(0);
+ let id = FRESH_VAR_COUNTER.fetch_add(1, Ordering::SeqCst);
+ NzVar::Fresh(id)
}
pub fn shift(&self, delta: isize) -> Self {
- NzVar {
- idx: (self.idx as isize + delta) as usize,
+ NzVar::new((self.idx() as isize + delta) as usize)
+ }
+ // Panics on a fresh variable.
+ pub fn idx(&self) -> usize {
+ match self {
+ NzVar::Bound(i) => *i,
+ NzVar::Fresh(_) => panic!(
+ "Trying to use a fresh variable outside of equality checking"
+ ),
}
}
}
diff --git a/dhall/src/semantics/tck/tyexpr.rs b/dhall/src/semantics/tck/tyexpr.rs
index a42265d..9e8dc47 100644
--- a/dhall/src/semantics/tck/tyexpr.rs
+++ b/dhall/src/semantics/tck/tyexpr.rs
@@ -12,7 +12,7 @@ use crate::syntax::{ExprKind, Label, Span, V};
pub(crate) type Type = Value;
// An expression with inferred types at every node and resolved variables.
-#[derive(Debug, Clone)]
+#[derive(Clone)]
pub(crate) struct TyExpr {
kind: Box<TyExprKind>,
ty: Option<Type>,
@@ -114,3 +114,16 @@ fn tyexpr_to_expr<'a>(
}
})
}
+
+impl std::fmt::Debug for TyExpr {
+ fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+ let mut x = fmt.debug_struct("TyExpr");
+ x.field("kind", self.kind());
+ if let Some(ty) = self.ty.as_ref() {
+ x.field("type", &ty);
+ } else {
+ x.field("type", &None::<()>);
+ }
+ x.finish()
+ }
+}
diff --git a/dhall/src/tests.rs b/dhall/src/tests.rs
index 88c09cc..971c48d 100644
--- a/dhall/src/tests.rs
+++ b/dhall/src/tests.rs
@@ -164,6 +164,7 @@ pub fn run_test(test: Test<'_>) -> Result<()> {
// let expr = parse_file_str(&expr_file_path)?.resolve()?.to_expr();
// let tyexpr = crate::semantics::nze::nzexpr::typecheck(expr)?;
// let ty = tyexpr.get_type()?.to_expr();
+ //
let expr = parse_file_str(&expr_file_path)?.resolve()?.to_expr();
let ty = crate::semantics::tck::typecheck::typecheck(&expr)?
.get_type()?
@@ -173,6 +174,23 @@ pub fn run_test(test: Test<'_>) -> Result<()> {
});
let expected = parse_file_str(&expected_file_path)?.to_expr();
assert_eq_display!(ty, expected);
+ //
+ // let expr = parse_file_str(&expr_file_path)?.resolve()?.to_expr();
+ // let ty = crate::semantics::tck::typecheck::typecheck(&expr)?
+ // .get_type()?;
+ // let expected = parse_file_str(&expected_file_path)?.to_expr();
+ // let expected = crate::semantics::tck::typecheck::typecheck(&expected)?
+ // .normalize_whnf_noenv();
+ // // if ty != expected {
+ // // assert_eq_display!(ty.to_expr(crate::semantics::phase::ToExprOptions {
+ // // alpha: false,
+ // // normalize: true,
+ // // }), expected.to_expr(crate::semantics::phase::ToExprOptions {
+ // // alpha: false,
+ // // normalize: true,
+ // // }))
+ // // }
+ // assert_eq_pretty!(ty, expected);
}
TypeInferenceFailure(file_path) => {
let mut res =
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-29 18:19:57 +0000