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-rw-r--r--dhall/src/phase/mod.rs10
-rw-r--r--dhall/src/phase/normalize.rs999
-rw-r--r--dhall/src/phase/typecheck.rs345
3 files changed, 160 insertions, 1194 deletions
diff --git a/dhall/src/phase/mod.rs b/dhall/src/phase/mod.rs
index 4262dc1..0faf6dd 100644
--- a/dhall/src/phase/mod.rs
+++ b/dhall/src/phase/mod.rs
@@ -4,11 +4,13 @@ use std::path::Path;
use dhall_syntax::{Const, Import, Span, SubExpr, X};
+use crate::core::context::TypecheckContext;
+use crate::core::thunk::Thunk;
+use crate::core::value::{AlphaVar, Value};
use crate::error::{Error, ImportError, TypeError, TypeMessage};
-use normalize::{AlphaVar, Thunk, Value};
use resolve::ImportRoot;
-use typecheck::{const_to_typed, type_of_const, TypecheckContext};
+use typecheck::{const_to_typed, type_of_const};
pub(crate) mod binary;
pub(crate) mod normalize;
@@ -305,6 +307,10 @@ impl Normalized {
pub(crate) fn to_type(self) -> Type {
self.0.to_type()
}
+ pub(crate) fn get_type(&self) -> Result<Cow<'_, Type>, TypeError> {
+ self.0.get_type()
+ }
+
pub(crate) fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
Normalized(self.0.shift(delta, var))
}
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs
index 2340bbd..a48c299 100644
--- a/dhall/src/phase/normalize.rs
+++ b/dhall/src/phase/normalize.rs
@@ -1,988 +1,16 @@
-#![allow(non_snake_case)]
use std::collections::BTreeMap;
-use std::rc::Rc;
-use dhall_proc_macros as dhall;
-use dhall_syntax::context::Context;
-use dhall_syntax::{
- rc, BinOp, Builtin, Const, ExprF, Integer, InterpolatedTextContents, Label,
- Natural, V, X,
-};
+use dhall_syntax::{BinOp, Builtin, ExprF, InterpolatedTextContents, Label, X};
-use crate::phase::{NormalizedSubExpr, ResolvedSubExpr, Type, Typed};
+use crate::core::context::NormalizationContext;
+use crate::core::thunk::{Thunk, TypeThunk};
+use crate::core::value::Value;
+use crate::phase::{NormalizedSubExpr, ResolvedSubExpr, Typed};
-type InputSubExpr = ResolvedSubExpr;
-type OutputSubExpr = NormalizedSubExpr;
+pub(crate) type InputSubExpr = ResolvedSubExpr;
+pub(crate) type OutputSubExpr = NormalizedSubExpr;
-/// Stores a pair of variables: a normal one and if relevant one
-/// that corresponds to the alpha-normalized version of the first one.
-#[derive(Debug, Clone, Eq)]
-pub(crate) struct AlphaVar {
- normal: V<Label>,
- alpha: Option<V<()>>,
-}
-
-impl AlphaVar {
- pub(crate) fn to_var(&self, alpha: bool) -> V<Label> {
- match (alpha, &self.alpha) {
- (true, Some(x)) => V("_".into(), x.1),
- _ => self.normal.clone(),
- }
- }
- pub(crate) fn from_var(normal: V<Label>) -> Self {
- AlphaVar {
- normal,
- alpha: None,
- }
- }
- pub(crate) fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
- AlphaVar {
- normal: self.normal.shift(delta, &var.normal),
- alpha: match (&self.alpha, &var.alpha) {
- (Some(x), Some(v)) => Some(x.shift(delta, v)),
- _ => None,
- },
- }
- }
-}
-
-/// Equality is up to alpha-equivalence.
-impl std::cmp::PartialEq for AlphaVar {
- fn eq(&self, other: &Self) -> bool {
- match (&self.alpha, &other.alpha) {
- (Some(x), Some(y)) => x == y,
- (None, None) => self.normal == other.normal,
- _ => false,
- }
- }
-}
-
-impl From<Label> for AlphaVar {
- fn from(x: Label) -> AlphaVar {
- AlphaVar {
- normal: V(x, 0),
- alpha: Some(V((), 0)),
- }
- }
-}
-impl<'a> From<&'a Label> for AlphaVar {
- fn from(x: &'a Label) -> AlphaVar {
- x.clone().into()
- }
-}
-impl From<AlphaLabel> for AlphaVar {
- fn from(x: AlphaLabel) -> AlphaVar {
- let l: Label = x.into();
- l.into()
- }
-}
-impl<'a> From<&'a AlphaLabel> for AlphaVar {
- fn from(x: &'a AlphaLabel) -> AlphaVar {
- x.clone().into()
- }
-}
-
-// Exactly like a Label, but equality returns always true.
-// This is so that Value equality is exactly alpha-equivalence.
-#[derive(Debug, Clone, Eq)]
-pub(crate) struct AlphaLabel(Label);
-
-impl AlphaLabel {
- fn to_label_maybe_alpha(&self, alpha: bool) -> Label {
- if alpha {
- "_".into()
- } else {
- self.to_label()
- }
- }
- fn to_label(&self) -> Label {
- self.clone().into()
- }
-}
-
-impl std::cmp::PartialEq for AlphaLabel {
- fn eq(&self, _other: &Self) -> bool {
- true
- }
-}
-
-impl From<Label> for AlphaLabel {
- fn from(x: Label) -> AlphaLabel {
- AlphaLabel(x)
- }
-}
-impl From<AlphaLabel> for Label {
- fn from(x: AlphaLabel) -> Label {
- x.0
- }
-}
-
-#[derive(Debug, Clone)]
-enum EnvItem {
- Thunk(Thunk),
- Skip(AlphaVar),
-}
-
-impl EnvItem {
- fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
- use EnvItem::*;
- match self {
- Thunk(e) => Thunk(e.shift(delta, var)),
- Skip(v) => Skip(v.shift(delta, var)),
- }
- }
-
- pub(crate) fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
- match self {
- EnvItem::Thunk(e) => EnvItem::Thunk(e.subst_shift(var, val)),
- EnvItem::Skip(v) if v == var => EnvItem::Thunk(val.to_thunk()),
- EnvItem::Skip(v) => EnvItem::Skip(v.shift(-1, var)),
- }
- }
-}
-
-#[derive(Debug, Clone)]
-pub(crate) struct NormalizationContext(Rc<Context<Label, EnvItem>>);
-
-impl NormalizationContext {
- pub(crate) fn new() -> Self {
- NormalizationContext(Rc::new(Context::new()))
- }
- fn skip(&self, x: &Label) -> Self {
- NormalizationContext(Rc::new(
- self.0
- .map(|_, e| e.shift(1, &x.into()))
- .insert(x.clone(), EnvItem::Skip(x.into())),
- ))
- }
- fn lookup(&self, var: &V<Label>) -> Value {
- let V(x, n) = var;
- match self.0.lookup(x, *n) {
- Some(EnvItem::Thunk(t)) => t.to_value(),
- Some(EnvItem::Skip(newvar)) => Value::Var(newvar.clone()),
- // Free variable
- None => Value::Var(AlphaVar::from_var(var.clone())),
- }
- }
- pub(crate) fn from_typecheck_ctx(
- tc_ctx: &crate::phase::typecheck::TypecheckContext,
- ) -> Self {
- use crate::phase::typecheck::EnvItem::*;
- let mut ctx = Context::new();
- for (k, vs) in tc_ctx.0.iter_keys() {
- for v in vs.iter() {
- let new_item = match v {
- Type(var, _) => EnvItem::Skip(var.clone()),
- Value(e) => EnvItem::Thunk(e.to_thunk()),
- };
- ctx = ctx.insert(k.clone(), new_item);
- }
- }
- NormalizationContext(Rc::new(ctx))
- }
-
- fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
- NormalizationContext(Rc::new(self.0.map(|_, e| e.shift(delta, var))))
- }
-
- fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
- NormalizationContext(Rc::new(
- self.0.map(|_, e| e.subst_shift(var, val)),
- ))
- }
-}
-
-/// A semantic value.
-/// Equality is up to alpha-equivalence (renaming of bound variables).
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub(crate) enum Value {
- /// Closures
- Lam(AlphaLabel, Thunk, Thunk),
- AppliedBuiltin(Builtin, Vec<Thunk>),
- /// `λ(x: a) -> Some x`
- OptionalSomeClosure(TypeThunk),
- /// `λ(x : a) -> λ(xs : List a) -> [ x ] # xs`
- /// `λ(xs : List a) -> [ x ] # xs`
- ListConsClosure(TypeThunk, Option<Thunk>),
- /// `λ(x : Natural) -> x + 1`
- NaturalSuccClosure,
- Pi(AlphaLabel, TypeThunk, TypeThunk),
-
- Var(AlphaVar),
- Const(Const),
- BoolLit(bool),
- NaturalLit(Natural),
- IntegerLit(Integer),
- EmptyOptionalLit(TypeThunk),
- NEOptionalLit(Thunk),
- EmptyListLit(TypeThunk),
- NEListLit(Vec<Thunk>),
- RecordLit(BTreeMap<Label, Thunk>),
- RecordType(BTreeMap<Label, TypeThunk>),
- UnionType(BTreeMap<Label, Option<TypeThunk>>),
- UnionConstructor(Label, BTreeMap<Label, Option<TypeThunk>>),
- UnionLit(Label, Thunk, BTreeMap<Label, Option<TypeThunk>>),
- TextLit(Vec<InterpolatedTextContents<Thunk>>),
- /// Invariant: This must not contain a value captured by one of the variants above.
- PartialExpr(ExprF<Thunk, Label, X>),
-}
-
-impl Value {
- pub(crate) fn into_thunk(self) -> Thunk {
- Thunk::from_value(self)
- }
-
- /// Convert the value to a fully normalized syntactic expression
- pub(crate) fn normalize_to_expr(&self) -> OutputSubExpr {
- self.normalize_to_expr_maybe_alpha(false)
- }
- /// Convert the value to a fully normalized syntactic expression. Also alpha-normalize
- /// if alpha is `true`
- pub(crate) fn normalize_to_expr_maybe_alpha(
- &self,
- alpha: bool,
- ) -> OutputSubExpr {
- match self {
- Value::Lam(x, t, e) => rc(ExprF::Lam(
- x.to_label_maybe_alpha(alpha),
- t.normalize_to_expr_maybe_alpha(alpha),
- e.normalize_to_expr_maybe_alpha(alpha),
- )),
- Value::AppliedBuiltin(b, args) => {
- let mut e = rc(ExprF::Builtin(*b));
- for v in args {
- e = rc(ExprF::App(
- e,
- v.normalize_to_expr_maybe_alpha(alpha),
- ));
- }
- e
- }
- Value::OptionalSomeClosure(n) => {
- let a = n.normalize_to_expr_maybe_alpha(alpha);
- dhall::subexpr!(λ(x: a) -> Some x)
- }
- Value::ListConsClosure(a, None) => {
- // Avoid accidental capture of the new `x` variable
- let a1 = a.shift(1, &Label::from("x").into());
- let a1 = a1.normalize_to_expr_maybe_alpha(alpha);
- let a = a.normalize_to_expr_maybe_alpha(alpha);
- dhall::subexpr!(λ(x : a) -> λ(xs : List a1) -> [ x ] # xs)
- }
- Value::ListConsClosure(n, Some(v)) => {
- // Avoid accidental capture of the new `xs` variable
- let v = v.shift(1, &Label::from("xs").into());
- let v = v.normalize_to_expr_maybe_alpha(alpha);
- let a = n.normalize_to_expr_maybe_alpha(alpha);
- dhall::subexpr!(λ(xs : List a) -> [ v ] # xs)
- }
- Value::NaturalSuccClosure => {
- dhall::subexpr!(λ(x : Natural) -> x + 1)
- }
- Value::Pi(x, t, e) => rc(ExprF::Pi(
- x.to_label_maybe_alpha(alpha),
- t.normalize_to_expr_maybe_alpha(alpha),
- e.normalize_to_expr_maybe_alpha(alpha),
- )),
- Value::Var(v) => rc(ExprF::Var(v.to_var(alpha))),
- Value::Const(c) => rc(ExprF::Const(*c)),
- Value::BoolLit(b) => rc(ExprF::BoolLit(*b)),
- Value::NaturalLit(n) => rc(ExprF::NaturalLit(*n)),
- Value::IntegerLit(n) => rc(ExprF::IntegerLit(*n)),
- Value::EmptyOptionalLit(n) => rc(ExprF::App(
- rc(ExprF::Builtin(Builtin::OptionalNone)),
- n.normalize_to_expr_maybe_alpha(alpha),
- )),
- Value::NEOptionalLit(n) => {
- rc(ExprF::SomeLit(n.normalize_to_expr_maybe_alpha(alpha)))
- }
- Value::EmptyListLit(n) => {
- rc(ExprF::EmptyListLit(n.normalize_to_expr_maybe_alpha(alpha)))
- }
- Value::NEListLit(elts) => rc(ExprF::NEListLit(
- elts.into_iter()
- .map(|n| n.normalize_to_expr_maybe_alpha(alpha))
- .collect(),
- )),
- Value::RecordLit(kvs) => rc(ExprF::RecordLit(
- kvs.iter()
- .map(|(k, v)| {
- (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
- })
- .collect(),
- )),
- Value::RecordType(kts) => rc(ExprF::RecordType(
- kts.iter()
- .map(|(k, v)| {
- (k.clone(), v.normalize_to_expr_maybe_alpha(alpha))
- })
- .collect(),
- )),
- Value::UnionType(kts) => rc(ExprF::UnionType(
- kts.iter()
- .map(|(k, v)| {
- (
- k.clone(),
- v.as_ref().map(|v| {
- v.normalize_to_expr_maybe_alpha(alpha)
- }),
- )
- })
- .collect(),
- )),
- Value::UnionConstructor(l, kts) => {
- let kts = kts
- .iter()
- .map(|(k, v)| {
- (
- k.clone(),
- v.as_ref().map(|v| {
- v.normalize_to_expr_maybe_alpha(alpha)
- }),
- )
- })
- .collect();
- rc(ExprF::Field(rc(ExprF::UnionType(kts)), l.clone()))
- }
- Value::UnionLit(l, v, kts) => rc(ExprF::UnionLit(
- l.clone(),
- v.normalize_to_expr_maybe_alpha(alpha),
- kts.iter()
- .map(|(k, v)| {
- (
- k.clone(),
- v.as_ref().map(|v| {
- v.normalize_to_expr_maybe_alpha(alpha)
- }),
- )
- })
- .collect(),
- )),
- Value::TextLit(elts) => {
- use InterpolatedTextContents::{Expr, Text};
- rc(ExprF::TextLit(
- elts.iter()
- .map(|contents| match contents {
- Expr(e) => {
- Expr(e.normalize_to_expr_maybe_alpha(alpha))
- }
- Text(s) => Text(s.clone()),
- })
- .collect(),
- ))
- }
- Value::PartialExpr(e) => {
- rc(e.map_ref_simple(|v| v.normalize_to_expr_maybe_alpha(alpha)))
- }
- }
- }
-
- // Deprecated
- fn normalize(&self) -> Value {
- let mut v = self.clone();
- v.normalize_mut();
- v
- }
-
- pub(crate) fn normalize_mut(&mut self) {
- match self {
- Value::NaturalSuccClosure
- | Value::Var(_)
- | Value::Const(_)
- | Value::BoolLit(_)
- | Value::NaturalLit(_)
- | Value::IntegerLit(_) => {}
-
- Value::EmptyOptionalLit(tth)
- | Value::OptionalSomeClosure(tth)
- | Value::EmptyListLit(tth) => {
- tth.normalize_mut();
- }
-
- Value::NEOptionalLit(th) => {
- th.normalize_mut();
- }
- Value::Lam(_, t, e) => {
- t.normalize_mut();
- e.normalize_mut();
- }
- Value::Pi(_, t, e) => {
- t.normalize_mut();
- e.normalize_mut();
- }
- Value::AppliedBuiltin(_, args) => {
- for x in args.iter_mut() {
- x.normalize_mut();
- }
- }
- Value::ListConsClosure(t, v) => {
- t.normalize_mut();
- for x in v.iter_mut() {
- x.normalize_mut();
- }
- }
- Value::NEListLit(elts) => {
- for x in elts.iter_mut() {
- x.normalize_mut();
- }
- }
- Value::RecordLit(kvs) => {
- for x in kvs.values_mut() {
- x.normalize_mut();
- }
- }
- Value::RecordType(kvs) => {
- for x in kvs.values_mut() {
- x.normalize_mut();
- }
- }
- Value::UnionType(kts) | Value::UnionConstructor(_, kts) => {
- for x in kts.values_mut().flat_map(|opt| opt) {
- x.normalize_mut();
- }
- }
- Value::UnionLit(_, v, kts) => {
- v.normalize_mut();
- for x in kts.values_mut().flat_map(|opt| opt) {
- x.normalize_mut();
- }
- }
- Value::TextLit(elts) => {
- for x in elts.iter_mut() {
- use InterpolatedTextContents::{Expr, Text};
- match x {
- Expr(n) => n.normalize_mut(),
- Text(_) => {}
- }
- }
- }
- Value::PartialExpr(e) => {
- // TODO: need map_mut_simple
- e.map_ref_simple(|v| {
- v.normalize_nf();
- });
- }
- }
- }
-
- /// Apply to a value
- pub(crate) fn app(self, val: Value) -> Value {
- self.app_val(val)
- }
-
- /// Apply to a value
- pub(crate) fn app_val(self, val: Value) -> Value {
- self.app_thunk(val.into_thunk())
- }
-
- /// Apply to a thunk
- pub(crate) fn app_thunk(self, th: Thunk) -> Value {
- Thunk::from_value(self).app_thunk(th)
- }
-
- pub(crate) fn from_builtin(b: Builtin) -> Value {
- Value::AppliedBuiltin(b, vec![])
- }
-
- fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
- match self {
- Value::Lam(x, t, e) => Value::Lam(
- x.clone(),
- t.shift(delta, var),
- e.shift(delta, &var.shift(1, &x.into())),
- ),
- Value::AppliedBuiltin(b, args) => Value::AppliedBuiltin(
- *b,
- args.iter().map(|v| v.shift(delta, var)).collect(),
- ),
- Value::NaturalSuccClosure => Value::NaturalSuccClosure,
- Value::OptionalSomeClosure(tth) => {
- Value::OptionalSomeClosure(tth.shift(delta, var))
- }
- Value::ListConsClosure(t, v) => Value::ListConsClosure(
- t.shift(delta, var),
- v.as_ref().map(|v| v.shift(delta, var)),
- ),
- Value::Pi(x, t, e) => Value::Pi(
- x.clone(),
- t.shift(delta, var),
- e.shift(delta, &var.shift(1, &x.into())),
- ),
- Value::Var(v) => Value::Var(v.shift(delta, var)),
- Value::Const(c) => Value::Const(*c),
- Value::BoolLit(b) => Value::BoolLit(*b),
- Value::NaturalLit(n) => Value::NaturalLit(*n),
- Value::IntegerLit(n) => Value::IntegerLit(*n),
- Value::EmptyOptionalLit(tth) => {
- Value::EmptyOptionalLit(tth.shift(delta, var))
- }
- Value::NEOptionalLit(th) => {
- Value::NEOptionalLit(th.shift(delta, var))
- }
- Value::EmptyListLit(tth) => {
- Value::EmptyListLit(tth.shift(delta, var))
- }
- Value::NEListLit(elts) => Value::NEListLit(
- elts.iter().map(|v| v.shift(delta, var)).collect(),
- ),
- Value::RecordLit(kvs) => Value::RecordLit(
- kvs.iter()
- .map(|(k, v)| (k.clone(), v.shift(delta, var)))
- .collect(),
- ),
- Value::RecordType(kvs) => Value::RecordType(
- kvs.iter()
- .map(|(k, v)| (k.clone(), v.shift(delta, var)))
- .collect(),
- ),
- Value::UnionType(kts) => Value::UnionType(
- kts.iter()
- .map(|(k, v)| {
- (k.clone(), v.as_ref().map(|v| v.shift(delta, var)))
- })
- .collect(),
- ),
- Value::UnionConstructor(x, kts) => Value::UnionConstructor(
- x.clone(),
- kts.iter()
- .map(|(k, v)| {
- (k.clone(), v.as_ref().map(|v| v.shift(delta, var)))
- })
- .collect(),
- ),
- Value::UnionLit(x, v, kts) => Value::UnionLit(
- x.clone(),
- v.shift(delta, var),
- kts.iter()
- .map(|(k, v)| {
- (k.clone(), v.as_ref().map(|v| v.shift(delta, var)))
- })
- .collect(),
- ),
- Value::TextLit(elts) => Value::TextLit(
- elts.iter()
- .map(|contents| {
- use InterpolatedTextContents::{Expr, Text};
- match contents {
- Expr(th) => Expr(th.shift(delta, var)),
- Text(s) => Text(s.clone()),
- }
- })
- .collect(),
- ),
- Value::PartialExpr(e) => {
- Value::PartialExpr(e.map_ref_with_special_handling_of_binders(
- |v| v.shift(delta, var),
- |x, v| v.shift(delta, &var.shift(1, &x.into())),
- X::clone,
- Label::clone,
- ))
- }
- }
- }
-
- pub(crate) fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
- match self {
- // Retry normalizing since substituting may allow progress
- Value::AppliedBuiltin(b, args) => apply_builtin(
- *b,
- args.iter().map(|v| v.subst_shift(var, val)).collect(),
- ),
- // Retry normalizing since substituting may allow progress
- Value::PartialExpr(e) => {
- normalize_one_layer(e.map_ref_with_special_handling_of_binders(
- |v| v.subst_shift(var, val),
- |x, v| {
- v.subst_shift(
- &var.shift(1, &x.into()),
- &val.shift(1, &x.into()),
- )
- },
- X::clone,
- Label::clone,
- ))
- }
- // Retry normalizing since substituting may allow progress
- Value::TextLit(elts) => {
- Value::TextLit(squash_textlit(elts.iter().map(|contents| {
- use InterpolatedTextContents::{Expr, Text};
- match contents {
- Expr(th) => Expr(th.subst_shift(var, val)),
- Text(s) => Text(s.clone()),
- }
- })))
- }
- Value::Lam(x, t, e) => Value::Lam(
- x.clone(),
- t.subst_shift(var, val),
- e.subst_shift(
- &var.shift(1, &x.into()),
- &val.shift(1, &x.into()),
- ),
- ),
- Value::NaturalSuccClosure => Value::NaturalSuccClosure,
- Value::OptionalSomeClosure(tth) => {
- Value::OptionalSomeClosure(tth.subst_shift(var, val))
- }
- Value::ListConsClosure(t, v) => Value::ListConsClosure(
- t.subst_shift(var, val),
- v.as_ref().map(|v| v.subst_shift(var, val)),
- ),
- Value::Pi(x, t, e) => Value::Pi(
- x.clone(),
- t.subst_shift(var, val),
- e.subst_shift(
- &var.shift(1, &x.into()),
- &val.shift(1, &x.into()),
- ),
- ),
- Value::Var(v) if v == var => val.to_value().clone(),
- Value::Var(v) => Value::Var(v.shift(-1, var)),
- Value::Const(c) => Value::Const(*c),
- Value::BoolLit(b) => Value::BoolLit(*b),
- Value::NaturalLit(n) => Value::NaturalLit(*n),
- Value::IntegerLit(n) => Value::IntegerLit(*n),
- Value::EmptyOptionalLit(tth) => {
- Value::EmptyOptionalLit(tth.subst_shift(var, val))
- }
- Value::NEOptionalLit(th) => {
- Value::NEOptionalLit(th.subst_shift(var, val))
- }
- Value::EmptyListLit(tth) => {
- Value::EmptyListLit(tth.subst_shift(var, val))
- }
- Value::NEListLit(elts) => Value::NEListLit(
- elts.iter().map(|v| v.subst_shift(var, val)).collect(),
- ),
- Value::RecordLit(kvs) => Value::RecordLit(
- kvs.iter()
- .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
- .collect(),
- ),
- Value::RecordType(kvs) => Value::RecordType(
- kvs.iter()
- .map(|(k, v)| (k.clone(), v.subst_shift(var, val)))
- .collect(),
- ),
- Value::UnionType(kts) => Value::UnionType(
- kts.iter()
- .map(|(k, v)| {
- (k.clone(), v.as_ref().map(|v| v.subst_shift(var, val)))
- })
- .collect(),
- ),
- Value::UnionConstructor(x, kts) => Value::UnionConstructor(
- x.clone(),
- kts.iter()
- .map(|(k, v)| {
- (k.clone(), v.as_ref().map(|v| v.subst_shift(var, val)))
- })
- .collect(),
- ),
- Value::UnionLit(x, v, kts) => Value::UnionLit(
- x.clone(),
- v.subst_shift(var, val),
- kts.iter()
- .map(|(k, v)| {
- (k.clone(), v.as_ref().map(|v| v.subst_shift(var, val)))
- })
- .collect(),
- ),
- }
- }
-}
-
-mod thunk {
- use super::{
- apply_any, normalize_whnf, AlphaVar, InputSubExpr,
- NormalizationContext, OutputSubExpr, Value,
- };
- use crate::phase::Typed;
- use std::cell::{Ref, RefCell};
- use std::rc::Rc;
-
- #[derive(Debug, Clone, Copy)]
- enum Marker {
- /// Weak Head Normal Form, i.e. subexpressions may not be normalized
- WHNF,
- /// Normal form, i.e. completely normalized
- NF,
- }
- use Marker::{NF, WHNF};
-
- #[derive(Debug)]
- enum ThunkInternal {
- /// Non-normalized value alongside a normalization context
- Unnormalized(NormalizationContext, InputSubExpr),
- /// Partially normalized value.
- /// Invariant: if the marker is `NF`, the value must be fully normalized
- Value(Marker, Value),
- }
-
- /// Stores a possibl unevaluated value. Uses RefCell to ensure that
- /// the value gets normalized at most once.
- #[derive(Debug, Clone)]
- pub struct Thunk(Rc<RefCell<ThunkInternal>>);
-
- impl ThunkInternal {
- fn into_thunk(self) -> Thunk {
- Thunk(Rc::new(RefCell::new(self)))
- }
-
- fn normalize_whnf(&mut self) {
- match self {
- ThunkInternal::Unnormalized(ctx, e) => {
- *self = ThunkInternal::Value(
- WHNF,
- normalize_whnf(ctx.clone(), e.clone()),
- )
- }
- // Already at least in WHNF
- ThunkInternal::Value(_, _) => {}
- }
- }
-
- fn normalize_nf(&mut self) {
- match self {
- ThunkInternal::Unnormalized(_, _) => {
- self.normalize_whnf();
- self.normalize_nf();
- }
- ThunkInternal::Value(m @ WHNF, v) => {
- v.normalize_mut();
- *m = NF;
- }
- // Already in NF
- ThunkInternal::Value(NF, _) => {}
- }
- }
-
- // Always use normalize_whnf before
- fn as_whnf(&self) -> &Value {
- match self {
- ThunkInternal::Unnormalized(_, _) => unreachable!(),
- ThunkInternal::Value(_, v) => v,
- }
- }
-
- // Always use normalize_nf before
- fn as_nf(&self) -> &Value {
- match self {
- ThunkInternal::Unnormalized(_, _) => unreachable!(),
- ThunkInternal::Value(WHNF, _) => unreachable!(),
- ThunkInternal::Value(NF, v) => v,
- }
- }
-
- fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
- match self {
- ThunkInternal::Unnormalized(ctx, e) => {
- ThunkInternal::Unnormalized(
- ctx.shift(delta, var),
- e.clone(),
- )
- }
- ThunkInternal::Value(m, v) => {
- ThunkInternal::Value(*m, v.shift(delta, var))
- }
- }
- }
-
- fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
- match self {
- ThunkInternal::Unnormalized(ctx, e) => {
- ThunkInternal::Unnormalized(
- ctx.subst_shift(var, val),
- e.clone(),
- )
- }
- ThunkInternal::Value(_, v) => {
- // The resulting value may not stay in normal form after substitution
- ThunkInternal::Value(WHNF, v.subst_shift(var, val))
- }
- }
- }
- }
-
- impl Thunk {
- pub(crate) fn new(ctx: NormalizationContext, e: InputSubExpr) -> Thunk {
- ThunkInternal::Unnormalized(ctx, e).into_thunk()
- }
-
- pub(crate) fn from_value(v: Value) -> Thunk {
- ThunkInternal::Value(WHNF, v).into_thunk()
- }
-
- pub(crate) fn from_normalized_expr(e: OutputSubExpr) -> Thunk {
- Thunk::new(
- NormalizationContext::new(),
- e.embed_absurd().note_absurd(),
- )
- }
-
- // Normalizes contents to normal form; faster than `normalize_nf` if
- // no one else shares this thunk
- pub(crate) fn normalize_mut(&mut self) {
- match Rc::get_mut(&mut self.0) {
- // Mutate directly if sole owner
- Some(refcell) => RefCell::get_mut(refcell).normalize_nf(),
- // Otherwise mutate through the refcell
- None => self.0.borrow_mut().normalize_nf(),
- }
- }
-
- fn do_normalize_whnf(&self) {
- let borrow = self.0.borrow();
- match &*borrow {
- ThunkInternal::Unnormalized(_, _) => {
- drop(borrow);
- self.0.borrow_mut().normalize_whnf();
- }
- // Already at least in WHNF
- ThunkInternal::Value(_, _) => {}
- }
- }
-
- fn do_normalize_nf(&self) {
- let borrow = self.0.borrow();
- match &*borrow {
- ThunkInternal::Unnormalized(_, _)
- | ThunkInternal::Value(WHNF, _) => {
- drop(borrow);
- self.0.borrow_mut().normalize_nf();
- }
- // Already in NF
- ThunkInternal::Value(NF, _) => {}
- }
- }
-
- // WARNING: avoid normalizing any thunk while holding on to this ref
- // or you could run into BorrowMut panics
- pub(crate) fn normalize_nf(&self) -> Ref<Value> {
- self.do_normalize_nf();
- Ref::map(self.0.borrow(), ThunkInternal::as_nf)
- }
-
- // WARNING: avoid normalizing any thunk while holding on to this ref
- // or you could run into BorrowMut panics
- pub(crate) fn as_value(&self) -> Ref<Value> {
- self.do_normalize_whnf();
- Ref::map(self.0.borrow(), ThunkInternal::as_whnf)
- }
-
- pub(crate) fn to_value(&self) -> Value {
- self.as_value().clone()
- }
-
- pub(crate) fn normalize_to_expr(&self) -> OutputSubExpr {
- self.normalize_to_expr_maybe_alpha(false)
- }
-
- pub(crate) fn normalize_to_expr_maybe_alpha(
- &self,
- alpha: bool,
- ) -> OutputSubExpr {
- self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
- }
-
- pub(crate) fn app_val(&self, val: Value) -> Value {
- self.app_thunk(val.into_thunk())
- }
-
- pub(crate) fn app_thunk(&self, th: Thunk) -> Value {
- apply_any(self.clone(), th)
- }
-
- pub(crate) fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
- self.0.borrow().shift(delta, var).into_thunk()
- }
-
- pub(crate) fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
- self.0.borrow().subst_shift(var, val).into_thunk()
- }
- }
-
- impl std::cmp::PartialEq for Thunk {
- fn eq(&self, other: &Self) -> bool {
- &*self.as_value() == &*other.as_value()
- }
- }
- impl std::cmp::Eq for Thunk {}
-}
-
-pub(crate) use thunk::Thunk;
-
-/// A thunk in type position.
-#[derive(Debug, Clone)]
-pub(crate) enum TypeThunk {
- Thunk(Thunk),
- Type(Type),
-}
-
-impl TypeThunk {
- fn from_value(v: Value) -> TypeThunk {
- TypeThunk::from_thunk(Thunk::from_value(v))
- }
-
- fn from_thunk(th: Thunk) -> TypeThunk {
- TypeThunk::Thunk(th)
- }
-
- pub(crate) fn from_type(t: Type) -> TypeThunk {
- TypeThunk::Type(t)
- }
-
- fn normalize_mut(&mut self) {
- match self {
- TypeThunk::Thunk(th) => th.normalize_mut(),
- TypeThunk::Type(_) => {}
- }
- }
-
- pub(crate) fn normalize_nf(&self) -> Value {
- match self {
- TypeThunk::Thunk(th) => th.normalize_nf().clone(),
- TypeThunk::Type(t) => t.to_value().normalize(),
- }
- }
-
- pub(crate) fn to_value(&self) -> Value {
- match self {
- TypeThunk::Thunk(th) => th.to_value(),
- TypeThunk::Type(t) => t.to_value(),
- }
- }
-
- pub(crate) fn normalize_to_expr_maybe_alpha(
- &self,
- alpha: bool,
- ) -> OutputSubExpr {
- self.normalize_nf().normalize_to_expr_maybe_alpha(alpha)
- }
-
- fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
- match self {
- TypeThunk::Thunk(th) => TypeThunk::Thunk(th.shift(delta, var)),
- TypeThunk::Type(t) => TypeThunk::Type(t.shift(delta, var)),
- }
- }
-
- pub(crate) fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self {
- match self {
- TypeThunk::Thunk(th) => TypeThunk::Thunk(th.subst_shift(var, val)),
- TypeThunk::Type(t) => TypeThunk::Type(t.subst_shift(var, val)),
- }
- }
-}
-
-impl std::cmp::PartialEq for TypeThunk {
- fn eq(&self, other: &Self) -> bool {
- self.to_value() == other.to_value()
- }
-}
-impl std::cmp::Eq for TypeThunk {}
-
-fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
+pub(crate) fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
use dhall_syntax::Builtin::*;
use Value::*;
@@ -1170,7 +198,7 @@ fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value {
}
}
-fn apply_any(f: Thunk, a: Thunk) -> Value {
+pub(crate) fn apply_any(f: Thunk, a: Thunk) -> Value {
let fallback = |f: Thunk, a: Thunk| Value::PartialExpr(ExprF::App(f, a));
let f_borrow = f.as_value();
@@ -1226,7 +254,7 @@ fn apply_any(f: Thunk, a: Thunk) -> Value {
}
}
-fn squash_textlit(
+pub(crate) fn squash_textlit(
elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>,
) -> Vec<InterpolatedTextContents<Thunk>> {
use std::mem::replace;
@@ -1269,7 +297,10 @@ fn squash_textlit(
}
/// Reduces the imput expression to a Value. Evaluates as little as possible.
-fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value {
+pub(crate) fn normalize_whnf(
+ ctx: NormalizationContext,
+ expr: InputSubExpr,
+) -> Value {
match expr.as_ref() {
ExprF::Embed(e) => return e.to_value(),
ExprF::Var(v) => return ctx.lookup(v),
@@ -1288,7 +319,7 @@ fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value {
normalize_one_layer(expr)
}
-fn normalize_one_layer(expr: ExprF<Thunk, Label, X>) -> Value {
+pub(crate) fn normalize_one_layer(expr: ExprF<Thunk, Label, X>) -> Value {
use Value::{
BoolLit, EmptyListLit, EmptyOptionalLit, IntegerLit, Lam, NEListLit,
NEOptionalLit, NaturalLit, Pi, RecordLit, RecordType, TextLit,
diff --git a/dhall/src/phase/typecheck.rs b/dhall/src/phase/typecheck.rs
index aee9892..42a4540 100644
--- a/dhall/src/phase/typecheck.rs
+++ b/dhall/src/phase/typecheck.rs
@@ -1,220 +1,18 @@
#![allow(non_snake_case)]
use std::borrow::Borrow;
-use std::borrow::Cow;
use std::collections::BTreeMap;
use dhall_proc_macros as dhall;
-use dhall_syntax::context::Context;
use dhall_syntax::{
rc, Builtin, Const, Expr, ExprF, InterpolatedTextContents, Label, Span,
- SubExpr, V, X,
+ SubExpr, X,
};
+use crate::core::context::{NormalizationContext, TypecheckContext};
+use crate::core::thunk::{Thunk, TypeThunk};
+use crate::core::value::Value;
use crate::error::{TypeError, TypeMessage};
-use crate::phase::normalize::{
- AlphaVar, NormalizationContext, Thunk, TypeThunk, Value,
-};
use crate::phase::{Normalized, Resolved, Type, TypeInternal, Typed};
-use crate::traits::DynamicType;
-
-impl TypeThunk {
- fn to_type(&self, ctx: &TypecheckContext) -> Result<Type, TypeError> {
- match self {
- TypeThunk::Type(t) => Ok(t.clone()),
- TypeThunk::Thunk(th) => {
- // TODO: rule out statically
- mktype(ctx, th.normalize_to_expr().embed_absurd().note_absurd())
- }
- }
- }
-}
-
-#[derive(Debug, Clone)]
-pub(crate) enum EnvItem {
- Type(AlphaVar, Type),
- Value(Normalized),
-}
-
-impl EnvItem {
- fn shift(&self, delta: isize, var: &AlphaVar) -> Self {
- use EnvItem::*;
- match self {
- Type(v, e) => Type(v.shift(delta, var), e.shift(delta, var)),
- Value(e) => Value(e.shift(delta, var)),
- }
- }
-}
-
-#[derive(Debug, Clone)]
-pub(crate) struct TypecheckContext(pub(crate) Context<Label, EnvItem>);
-
-impl TypecheckContext {
- pub(crate) fn new() -> Self {
- TypecheckContext(Context::new())
- }
- pub(crate) fn insert_type(&self, x: &Label, t: Type) -> Self {
- TypecheckContext(
- self.0.map(|_, e| e.shift(1, &x.into())).insert(
- x.clone(),
- EnvItem::Type(x.into(), t.shift(1, &x.into())),
- ),
- )
- }
- pub(crate) fn insert_value(&self, x: &Label, t: Normalized) -> Self {
- TypecheckContext(self.0.insert(x.clone(), EnvItem::Value(t)))
- }
- pub(crate) fn lookup(&self, var: &V<Label>) -> Option<Cow<'_, Type>> {
- let V(x, n) = var;
- match self.0.lookup(x, *n) {
- Some(EnvItem::Type(_, t)) => Some(Cow::Borrowed(&t)),
- Some(EnvItem::Value(t)) => Some(t.get_type()?),
- None => None,
- }
- }
- fn to_normalization_ctx(&self) -> NormalizationContext {
- NormalizationContext::from_typecheck_ctx(self)
- }
-}
-
-impl PartialEq for TypecheckContext {
- fn eq(&self, _: &Self) -> bool {
- // don't count contexts when comparing stuff
- // this is dirty but needed for now
- true
- }
-}
-impl Eq for TypecheckContext {}
-
-fn function_check(a: Const, b: Const) -> Result<Const, ()> {
- use dhall_syntax::Const::*;
- match (a, b) {
- (_, Type) => Ok(Type),
- (Kind, Kind) => Ok(Kind),
- (Sort, Sort) => Ok(Sort),
- (Sort, Kind) => Ok(Sort),
- _ => Err(()),
- }
-}
-
-// Equality up to alpha-equivalence (renaming of bound variables)
-fn prop_equal<T, U>(eL0: T, eR0: U) -> bool
-where
- T: Borrow<Type>,
- U: Borrow<Type>,
-{
- eL0.borrow().to_value() == eR0.borrow().to_value()
-}
-
-pub(crate) fn const_to_typed(c: Const) -> Typed {
- match c {
- Const::Sort => Typed::const_sort(),
- _ => Typed::from_thunk_and_type(
- Value::Const(c).into_thunk(),
- type_of_const(c).unwrap(),
- ),
- }
-}
-
-fn const_to_type(c: Const) -> Type {
- Type(TypeInternal::Const(c))
-}
-
-pub(crate) fn type_of_const(c: Const) -> Result<Type, TypeError> {
- match c {
- Const::Type => Ok(Type::const_kind()),
- Const::Kind => Ok(Type::const_sort()),
- Const::Sort => {
- return Err(TypeError::new(
- &TypecheckContext::new(),
- TypeMessage::Sort,
- ))
- }
- }
-}
-
-fn type_of_builtin<E>(b: Builtin) -> Expr<X, E> {
- use dhall_syntax::Builtin::*;
- match b {
- Bool | Natural | Integer | Double | Text => dhall::expr!(Type),
- List | Optional => dhall::expr!(
- Type -> Type
- ),
-
- NaturalFold => dhall::expr!(
- Natural ->
- forall (natural: Type) ->
- forall (succ: natural -> natural) ->
- forall (zero: natural) ->
- natural
- ),
- NaturalBuild => dhall::expr!(
- (forall (natural: Type) ->
- forall (succ: natural -> natural) ->
- forall (zero: natural) ->
- natural) ->
- Natural
- ),
- NaturalIsZero | NaturalEven | NaturalOdd => dhall::expr!(
- Natural -> Bool
- ),
- NaturalToInteger => dhall::expr!(Natural -> Integer),
- NaturalShow => dhall::expr!(Natural -> Text),
-
- IntegerToDouble => dhall::expr!(Integer -> Double),
- IntegerShow => dhall::expr!(Integer -> Text),
- DoubleShow => dhall::expr!(Double -> Text),
- TextShow => dhall::expr!(Text -> Text),
-
- ListBuild => dhall::expr!(
- forall (a: Type) ->
- (forall (list: Type) ->
- forall (cons: a -> list -> list) ->
- forall (nil: list) ->
- list) ->
- List a
- ),
- ListFold => dhall::expr!(
- forall (a: Type) ->
- List a ->
- forall (list: Type) ->
- forall (cons: a -> list -> list) ->
- forall (nil: list) ->
- list
- ),
- ListLength => dhall::expr!(forall (a: Type) -> List a -> Natural),
- ListHead | ListLast => {
- dhall::expr!(forall (a: Type) -> List a -> Optional a)
- }
- ListIndexed => dhall::expr!(
- forall (a: Type) ->
- List a ->
- List { index: Natural, value: a }
- ),
- ListReverse => dhall::expr!(
- forall (a: Type) -> List a -> List a
- ),
-
- OptionalBuild => dhall::expr!(
- forall (a: Type) ->
- (forall (optional: Type) ->
- forall (just: a -> optional) ->
- forall (nothing: optional) ->
- optional) ->
- Optional a
- ),
- OptionalFold => dhall::expr!(
- forall (a: Type) ->
- Optional a ->
- forall (optional: Type) ->
- forall (just: a -> optional) ->
- forall (nothing: optional) ->
- optional
- ),
- OptionalNone => dhall::expr!(
- forall (a: Type) -> Optional a
- ),
- }
-}
macro_rules! ensure_equal {
($x:expr, $y:expr, $err:expr $(,)*) => {
@@ -399,16 +197,147 @@ impl TypeIntermediate {
}
}
+fn function_check(a: Const, b: Const) -> Result<Const, ()> {
+ use dhall_syntax::Const::*;
+ match (a, b) {
+ (_, Type) => Ok(Type),
+ (Kind, Kind) => Ok(Kind),
+ (Sort, Sort) => Ok(Sort),
+ (Sort, Kind) => Ok(Sort),
+ _ => Err(()),
+ }
+}
+
+// Equality up to alpha-equivalence (renaming of bound variables)
+fn prop_equal<T, U>(eL0: T, eR0: U) -> bool
+where
+ T: Borrow<Type>,
+ U: Borrow<Type>,
+{
+ eL0.borrow().to_value() == eR0.borrow().to_value()
+}
+
+pub(crate) fn const_to_typed(c: Const) -> Typed {
+ match c {
+ Const::Sort => Typed::const_sort(),
+ _ => Typed::from_thunk_and_type(
+ Value::Const(c).into_thunk(),
+ type_of_const(c).unwrap(),
+ ),
+ }
+}
+
+fn const_to_type(c: Const) -> Type {
+ Type(TypeInternal::Const(c))
+}
+
+pub(crate) fn type_of_const(c: Const) -> Result<Type, TypeError> {
+ match c {
+ Const::Type => Ok(Type::const_kind()),
+ Const::Kind => Ok(Type::const_sort()),
+ Const::Sort => {
+ return Err(TypeError::new(
+ &TypecheckContext::new(),
+ TypeMessage::Sort,
+ ))
+ }
+ }
+}
+
+fn type_of_builtin<E>(b: Builtin) -> Expr<X, E> {
+ use dhall_syntax::Builtin::*;
+ match b {
+ Bool | Natural | Integer | Double | Text => dhall::expr!(Type),
+ List | Optional => dhall::expr!(
+ Type -> Type
+ ),
+
+ NaturalFold => dhall::expr!(
+ Natural ->
+ forall (natural: Type) ->
+ forall (succ: natural -> natural) ->
+ forall (zero: natural) ->
+ natural
+ ),
+ NaturalBuild => dhall::expr!(
+ (forall (natural: Type) ->
+ forall (succ: natural -> natural) ->
+ forall (zero: natural) ->
+ natural) ->
+ Natural
+ ),
+ NaturalIsZero | NaturalEven | NaturalOdd => dhall::expr!(
+ Natural -> Bool
+ ),
+ NaturalToInteger => dhall::expr!(Natural -> Integer),
+ NaturalShow => dhall::expr!(Natural -> Text),
+
+ IntegerToDouble => dhall::expr!(Integer -> Double),
+ IntegerShow => dhall::expr!(Integer -> Text),
+ DoubleShow => dhall::expr!(Double -> Text),
+ TextShow => dhall::expr!(Text -> Text),
+
+ ListBuild => dhall::expr!(
+ forall (a: Type) ->
+ (forall (list: Type) ->
+ forall (cons: a -> list -> list) ->
+ forall (nil: list) ->
+ list) ->
+ List a
+ ),
+ ListFold => dhall::expr!(
+ forall (a: Type) ->
+ List a ->
+ forall (list: Type) ->
+ forall (cons: a -> list -> list) ->
+ forall (nil: list) ->
+ list
+ ),
+ ListLength => dhall::expr!(forall (a: Type) -> List a -> Natural),
+ ListHead | ListLast => {
+ dhall::expr!(forall (a: Type) -> List a -> Optional a)
+ }
+ ListIndexed => dhall::expr!(
+ forall (a: Type) ->
+ List a ->
+ List { index: Natural, value: a }
+ ),
+ ListReverse => dhall::expr!(
+ forall (a: Type) -> List a -> List a
+ ),
+
+ OptionalBuild => dhall::expr!(
+ forall (a: Type) ->
+ (forall (optional: Type) ->
+ forall (just: a -> optional) ->
+ forall (nothing: optional) ->
+ optional) ->
+ Optional a
+ ),
+ OptionalFold => dhall::expr!(
+ forall (a: Type) ->
+ Optional a ->
+ forall (optional: Type) ->
+ forall (just: a -> optional) ->
+ forall (nothing: optional) ->
+ optional
+ ),
+ OptionalNone => dhall::expr!(
+ forall (a: Type) -> Optional a
+ ),
+ }
+}
+
/// Takes an expression that is meant to contain a Type
/// and turn it into a type, typechecking it along the way.
-fn mktype(
+pub(crate) fn mktype(
ctx: &TypecheckContext,
e: SubExpr<Span, Normalized>,
) -> Result<Type, TypeError> {
Ok(type_with(ctx, e)?.to_type())
}
-fn builtin_to_type(b: Builtin) -> Result<Type, TypeError> {
+pub(crate) fn builtin_to_type(b: Builtin) -> Result<Type, TypeError> {
mktype(
&TypecheckContext::new(),
SubExpr::from_expr_no_note(ExprF::Builtin(b)),
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-28 03:09:03 +0000