diff options
Diffstat (limited to 'dhall/src')
| -rw-r--r-- | dhall/src/api/traits/static_type.rs | 2 | ||||
| -rw-r--r-- | dhall/src/core/context.rs | 136 | ||||
| -rw-r--r-- | dhall/src/core/mod.rs | 3 | ||||
| -rw-r--r-- | dhall/src/core/thunk.rs | 295 | ||||
| -rw-r--r-- | dhall/src/core/value.rs | 616 | ||||
| -rw-r--r-- | dhall/src/error/mod.rs | 2 | ||||
| -rw-r--r-- | dhall/src/lib.rs | 8 | ||||
| -rw-r--r-- | dhall/src/phase/mod.rs | 10 | ||||
| -rw-r--r-- | dhall/src/phase/normalize.rs | 999 | ||||
| -rw-r--r-- | dhall/src/phase/typecheck.rs | 345 |
10 files changed, 1217 insertions, 1199 deletions
diff --git a/dhall/src/api/traits/static_type.rs b/dhall/src/api/traits/static_type.rs index 8b141a0..e05dfff 100644 --- a/dhall/src/api/traits/static_type.rs +++ b/dhall/src/api/traits/static_type.rs @@ -39,7 +39,7 @@ fn mktype(x: SubExpr<X, X>) -> SimpleType { impl<T: SimpleStaticType> StaticType for T { fn get_static_type() -> Type { crate::phase::Normalized::from_thunk_and_type( - crate::phase::normalize::Thunk::from_normalized_expr( + crate::core::thunk::Thunk::from_normalized_expr( T::get_simple_static_type().into(), ), Type::const_type(), diff --git a/dhall/src/core/context.rs b/dhall/src/core/context.rs new file mode 100644 index 0000000..9b5beed --- /dev/null +++ b/dhall/src/core/context.rs @@ -0,0 +1,136 @@ +use std::borrow::Cow; +use std::rc::Rc; + +use dhall_syntax::context::Context; +use dhall_syntax::{Label, V}; + +use crate::core::thunk::Thunk; +use crate::core::value::{AlphaVar, Value}; +use crate::phase::{Normalized, Type, Typed}; + +#[derive(Debug, Clone)] +enum NzEnvItem { + Thunk(Thunk), + Skip(AlphaVar), +} + +#[derive(Debug, Clone)] +pub(crate) struct NormalizationContext(Rc<Context<Label, NzEnvItem>>); + +#[derive(Debug, Clone)] +pub(crate) enum TyEnvItem { + Type(AlphaVar, Type), + Value(Normalized), +} + +#[derive(Debug, Clone)] +pub(crate) struct TypecheckContext(pub(crate) Context<Label, TyEnvItem>); + +impl NzEnvItem { + pub(crate) fn shift(&self, delta: isize, var: &AlphaVar) -> Self { + use NzEnvItem::*; + 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 { + NzEnvItem::Thunk(e) => NzEnvItem::Thunk(e.subst_shift(var, val)), + NzEnvItem::Skip(v) if v == var => NzEnvItem::Thunk(val.to_thunk()), + NzEnvItem::Skip(v) => NzEnvItem::Skip(v.shift(-1, var)), + } + } +} + +impl NormalizationContext { + pub(crate) fn new() -> Self { + NormalizationContext(Rc::new(Context::new())) + } + pub(crate) fn skip(&self, x: &Label) -> Self { + NormalizationContext(Rc::new( + self.0 + .map(|_, e| e.shift(1, &x.into())) + .insert(x.clone(), NzEnvItem::Skip(x.into())), + )) + } + pub(crate) fn lookup(&self, var: &V<Label>) -> Value { + let V(x, n) = var; + match self.0.lookup(x, *n) { + Some(NzEnvItem::Thunk(t)) => t.to_value(), + Some(NzEnvItem::Skip(newvar)) => Value::Var(newvar.clone()), + // Free variable + None => Value::Var(AlphaVar::from_var(var.clone())), + } + } + pub(crate) fn from_typecheck_ctx(tc_ctx: &TypecheckContext) -> Self { + use TyEnvItem::*; + 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, _) => NzEnvItem::Skip(var.clone()), + Value(e) => NzEnvItem::Thunk(e.to_thunk()), + }; + ctx = ctx.insert(k.clone(), new_item); + } + } + NormalizationContext(Rc::new(ctx)) + } + + pub(crate) fn shift(&self, delta: isize, var: &AlphaVar) -> Self { + NormalizationContext(Rc::new(self.0.map(|_, e| e.shift(delta, var)))) + } + + pub(crate) fn subst_shift(&self, var: &AlphaVar, val: &Typed) -> Self { + NormalizationContext(Rc::new( + self.0.map(|_, e| e.subst_shift(var, val)), + )) + } +} + +impl TyEnvItem { + fn shift(&self, delta: isize, var: &AlphaVar) -> Self { + use TyEnvItem::*; + match self { + Type(v, e) => Type(v.shift(delta, var), e.shift(delta, var)), + Value(e) => Value(e.shift(delta, var)), + } + } +} + +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(), + TyEnvItem::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(), TyEnvItem::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(TyEnvItem::Type(_, t)) => Some(Cow::Borrowed(&t)), + Some(TyEnvItem::Value(t)) => Some(t.get_type()?), + None => None, + } + } + pub(crate) 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 {} diff --git a/dhall/src/core/mod.rs b/dhall/src/core/mod.rs new file mode 100644 index 0000000..8f5c2ca --- /dev/null +++ b/dhall/src/core/mod.rs @@ -0,0 +1,3 @@ +pub(crate) mod context; +pub(crate) mod thunk; +pub(crate) mod value; diff --git a/dhall/src/core/thunk.rs b/dhall/src/core/thunk.rs new file mode 100644 index 0000000..8775ce2 --- /dev/null +++ b/dhall/src/core/thunk.rs @@ -0,0 +1,295 @@ +use std::cell::{Ref, RefCell}; +use std::rc::Rc; + +use crate::core::context::NormalizationContext; +use crate::core::context::TypecheckContext; +use crate::core::value::{AlphaVar, Value}; +use crate::error::TypeError; +use crate::phase::normalize::{ + apply_any, normalize_whnf, InputSubExpr, OutputSubExpr, +}; +use crate::phase::typecheck::mktype; +use crate::phase::{Type, Typed}; + +#[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 possibly unevaluated value. Uses RefCell to ensure that +/// the value gets normalized at most once. +#[derive(Debug, Clone)] +pub struct Thunk(Rc<RefCell<ThunkInternal>>); + +/// A thunk in type position. +#[derive(Debug, Clone)] +pub(crate) enum TypeThunk { + Thunk(Thunk), + Type(Type), +} + +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 TypeThunk { + pub(crate) fn from_value(v: Value) -> TypeThunk { + TypeThunk::from_thunk(Thunk::from_value(v)) + } + + pub(crate) fn from_thunk(th: Thunk) -> TypeThunk { + TypeThunk::Thunk(th) + } + + pub(crate) fn from_type(t: Type) -> TypeThunk { + TypeThunk::Type(t) + } + + pub(crate) 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 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()) + } + } + } + + pub(crate) fn normalize_to_expr_maybe_alpha( + &self, + alpha: bool, + ) -> OutputSubExpr { + self.normalize_nf().normalize_to_expr_maybe_alpha(alpha) + } + + pub(crate) 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 Thunk { + fn eq(&self, other: &Self) -> bool { + &*self.as_value() == &*other.as_value() + } +} +impl std::cmp::Eq for Thunk {} + +impl std::cmp::PartialEq for TypeThunk { + fn eq(&self, other: &Self) -> bool { + self.to_value() == other.to_value() + } +} +impl std::cmp::Eq for TypeThunk {} diff --git a/dhall/src/core/value.rs b/dhall/src/core/value.rs new file mode 100644 index 0000000..31193d2 --- /dev/null +++ b/dhall/src/core/value.rs @@ -0,0 +1,616 @@ +use std::collections::BTreeMap; + +use dhall_proc_macros as dhall; +use dhall_syntax::{ + rc, Builtin, Const, ExprF, Integer, InterpolatedTextContents, Label, + Natural, V, X, +}; + +use crate::core::thunk::{Thunk, TypeThunk}; +use crate::phase::normalize::{ + apply_builtin, normalize_one_layer, squash_textlit, OutputSubExpr, +}; +use crate::phase::Typed; + +/// Stores a pair of variables: a normal one and if relevant one +/// that corresponds to the alpha-normalized version of the first one. +/// Equality is up to alpha-equivalence. +#[derive(Debug, Clone, Eq)] +pub(crate) struct AlphaVar { + normal: V<Label>, + alpha: Option<V<()>>, +} + +// 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); + +/// A semantic value. +/// Equality is up to alpha-equivalence (renaming of bound variables) +/// and beta-equivalence (normalization). +#[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 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, + }, + } + } +} + +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 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 + pub(crate) 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![]) + } + + pub(crate) 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(), + ), + } + } +} + +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 std::cmp::PartialEq for AlphaLabel { + fn eq(&self, _other: &Self) -> bool { + true + } +} + +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() + } +} + +impl From<Label> for AlphaLabel { + fn from(x: Label) -> AlphaLabel { + AlphaLabel(x) + } +} +impl From<AlphaLabel> for Label { + fn from(x: AlphaLabel) -> Label { + x.0 + } +} diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs index e70b9a9..f84d078 100644 --- a/dhall/src/error/mod.rs +++ b/dhall/src/error/mod.rs @@ -2,8 +2,8 @@ use std::io::Error as IOError; use dhall_syntax::{BinOp, Import, Label, ParseError, V}; +use crate::core::context::TypecheckContext; use crate::phase::resolve::ImportStack; -use crate::phase::typecheck::TypecheckContext; use crate::phase::{Normalized, Type, Typed}; pub type Result<T> = std::result::Result<T, Error>; diff --git a/dhall/src/lib.rs b/dhall/src/lib.rs index 989170a..8d1496a 100644 --- a/dhall/src/lib.rs +++ b/dhall/src/lib.rs @@ -123,8 +123,10 @@ #[macro_use] mod tests; -mod api; +pub(crate) mod api; +pub(crate) mod core; pub mod error; -mod phase; -pub use api::de; +pub(crate) mod phase; pub(crate) use api::traits; + +pub use api::de; 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)), |