diff options
Diffstat (limited to 'dhall/src/expr.rs')
| -rw-r--r-- | dhall/src/expr.rs | 208 |
1 files changed, 157 insertions, 51 deletions
diff --git a/dhall/src/expr.rs b/dhall/src/expr.rs index bb1a4e4..4d55f4a 100644 --- a/dhall/src/expr.rs +++ b/dhall/src/expr.rs @@ -1,4 +1,5 @@ use crate::imports::ImportRoot; +use crate::normalize::{Thunk, Value}; use dhall_core::*; use std::marker::PhantomData; @@ -10,6 +11,8 @@ macro_rules! derive_other_traits { } } + impl<'a> std::cmp::Eq for $ty<'a> {} + impl<'a> std::fmt::Display for $ty<'a> { fn fmt( &self, @@ -21,34 +24,149 @@ macro_rules! derive_other_traits { }; } -#[derive(Debug, Clone, Eq)] +#[derive(Debug, Clone)] pub(crate) struct Parsed<'a>( pub(crate) SubExpr<Span<'a>, Import>, pub(crate) ImportRoot, ); derive_other_traits!(Parsed); -#[derive(Debug, Clone, Eq)] +#[derive(Debug, Clone)] pub(crate) struct Resolved<'a>( pub(crate) SubExpr<Span<'a>, Normalized<'static>>, ); derive_other_traits!(Resolved); -#[derive(Debug, Clone, Eq)] +pub(crate) use self::typed::TypedInternal; + +#[derive(Debug, Clone)] pub(crate) struct Typed<'a>( - pub(crate) SubExpr<X, Normalized<'static>>, - pub(crate) Option<Type<'static>>, + pub(crate) TypedInternal, pub(crate) PhantomData<&'a ()>, ); -derive_other_traits!(Typed); -#[derive(Debug, Clone, Eq)] +#[derive(Debug, Clone)] pub(crate) struct Normalized<'a>( - pub(crate) SubExpr<X, X>, - pub(crate) Option<Type<'static>>, + pub(crate) TypedInternal, pub(crate) PhantomData<&'a ()>, ); -derive_other_traits!(Normalized); + +impl<'a> std::cmp::PartialEq for Normalized<'a> { + fn eq(&self, other: &Self) -> bool { + self.to_expr() == other.to_expr() + } +} + +impl<'a> std::cmp::Eq for Normalized<'a> {} + +impl<'a> std::fmt::Display for Normalized<'a> { + fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> { + self.to_expr().fmt(f) + } +} + +mod typed { + use super::{Type, Typed}; + use crate::normalize::{Thunk, Value}; + use crate::typecheck::{ + TypeError, TypeInternal, TypeMessage, TypecheckContext, + }; + use dhall_core::{Const, Label, SubExpr, V, X}; + use std::borrow::Cow; + use std::marker::PhantomData; + + #[derive(Debug, Clone)] + pub(crate) enum TypedInternal { + // The `Sort` higher-kinded type doesn't have a type + Sort, + // Any other value, along with its type + Value(Thunk, Option<Type<'static>>), + } + + impl TypedInternal { + pub(crate) fn from_thunk_and_type(th: Thunk, t: Type<'static>) -> Self { + TypedInternal::Value(th, Some(t)) + } + + pub(crate) fn from_thunk_untyped(th: Thunk) -> Self { + TypedInternal::Value(th, None) + } + + // TODO: Avoid cloning if possible + pub(crate) fn to_value(&self) -> Value { + match self { + TypedInternal::Value(th, _) => th.normalize_whnf().clone(), + TypedInternal::Sort => Value::Const(Const::Sort), + } + } + + pub(crate) fn to_expr(&self) -> SubExpr<X, X> { + self.to_value().normalize_to_expr() + } + + pub(crate) fn to_thunk(&self) -> Thunk { + match self { + TypedInternal::Value(th, _) => th.clone(), + TypedInternal::Sort => { + Thunk::from_whnf(Value::Const(Const::Sort)) + } + } + } + + pub(crate) fn to_type(&self) -> Type<'static> { + match self { + TypedInternal::Sort => Type(TypeInternal::Const(Const::Sort)), + TypedInternal::Value(th, _) => match &*th.normalize_whnf() { + Value::Const(c) => Type(TypeInternal::Const(*c)), + _ => Type(TypeInternal::Typed(Box::new(Typed( + self.clone(), + PhantomData, + )))), + }, + } + } + + pub(crate) fn get_type( + &self, + ) -> Result<Cow<'_, Type<'static>>, TypeError> { + match self { + TypedInternal::Value(_, Some(t)) => Ok(Cow::Borrowed(t)), + TypedInternal::Value(_, None) => Err(TypeError::new( + &TypecheckContext::new(), + TypeMessage::Untyped, + )), + TypedInternal::Sort => Err(TypeError::new( + &TypecheckContext::new(), + TypeMessage::Sort, + )), + } + } + + pub(crate) fn shift(&self, delta: isize, var: &V<Label>) -> Self { + match self { + TypedInternal::Value(th, t) => TypedInternal::Value( + th.shift(delta, var), + t.as_ref().map(|x| x.shift(delta, var)), + ), + TypedInternal::Sort => TypedInternal::Sort, + } + } + + pub(crate) fn subst_shift( + &self, + var: &V<Label>, + val: &Typed<'static>, + ) -> Self { + match self { + TypedInternal::Value(th, t) => TypedInternal::Value( + th.subst_shift(var, val), + t.as_ref().map(|x| x.subst_shift(var, val)), + ), + TypedInternal::Sort => TypedInternal::Sort, + } + } + } +} /// A Dhall expression representing a simple type. /// @@ -56,13 +174,15 @@ derive_other_traits!(Normalized); /// `Bool`, `{ x: Integer }` or `Natural -> Text`. /// /// For a more general notion of "type", see [Type]. -#[derive(Debug, Clone, Eq)] +#[derive(Debug, Clone)] pub struct SimpleType<'a>( pub(crate) SubExpr<X, X>, pub(crate) PhantomData<&'a ()>, ); derive_other_traits!(SimpleType); +pub(crate) use crate::typecheck::TypeInternal; + /// A Dhall expression representing a (possibly higher-kinded) type. /// /// This includes [SimpleType]s but also higher-kinded expressions like @@ -70,12 +190,10 @@ derive_other_traits!(SimpleType); #[derive(Debug, Clone, PartialEq, Eq)] pub struct Type<'a>(pub(crate) TypeInternal<'a>); -#[derive(Debug, Clone, PartialEq, Eq)] -pub(crate) enum TypeInternal<'a> { - Expr(Box<Normalized<'a>>), - Const(dhall_core::Const), - /// The type of `Sort` - SuperType, +impl<'a> std::fmt::Display for Type<'a> { + fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> { + self.to_normalized().fmt(f) + } } // Exposed for the macros @@ -98,50 +216,38 @@ impl<'a> From<SubExpr<X, X>> for SimpleType<'a> { #[doc(hidden)] impl<'a> From<Normalized<'a>> for Typed<'a> { fn from(x: Normalized<'a>) -> Typed<'a> { - Typed(x.0.embed_absurd(), x.1, x.2) + Typed(x.0, x.1) } } -#[doc(hidden)] -impl<'a> Typed<'a> { - pub(crate) fn as_expr(&self) -> &SubExpr<X, Normalized<'a>> { - &self.0 - } -} - -#[doc(hidden)] impl<'a> Normalized<'a> { - pub(crate) fn as_expr(&self) -> &SubExpr<X, X> { - &self.0 + pub(crate) fn from_thunk_and_type(th: Thunk, t: Type<'static>) -> Self { + Normalized(TypedInternal::from_thunk_and_type(th, t), PhantomData) } - pub(crate) fn into_expr(self) -> SubExpr<X, X> { - self.0 + // Deprecated + pub(crate) fn as_expr(&self) -> SubExpr<X, X> { + self.0.to_expr() } - pub(crate) fn unnote<'b>(self) -> Normalized<'b> { - Normalized(self.0, self.1, PhantomData) + pub(crate) fn to_expr(&self) -> SubExpr<X, X> { + self.0.to_expr() } - pub(crate) fn into_type(self) -> Type<'a> { - Type(match self.0.as_ref() { - ExprF::Const(c) => TypeInternal::Const(*c), - _ => TypeInternal::Expr(Box::new(self)), - }) + pub(crate) fn to_value(&self) -> Value { + self.0.to_value() } -} - -#[doc(hidden)] -impl<'a> Type<'a> { - pub(crate) fn unnote<'b>(self) -> Type<'b> { - use TypeInternal::*; - Type(match self.0 { - Expr(e) => Expr(Box::new(e.unnote())), - Const(c) => Const(c), - SuperType => SuperType, - }) + #[allow(dead_code)] + pub(crate) fn unnote<'b>(self) -> Normalized<'b> { + Normalized(self.0, PhantomData) } } -impl<'a> SimpleType<'a> { - pub(crate) fn into_type(self) -> Type<'a> { - Normalized(self.0, Some(Type::const_type()), PhantomData).into_type() +impl<'a> Typed<'a> { + pub(crate) fn from_thunk_and_type(th: Thunk, t: Type<'static>) -> Self { + Typed(TypedInternal::from_thunk_and_type(th, t), PhantomData) + } + pub(crate) fn from_thunk_untyped(th: Thunk) -> Self { + Typed(TypedInternal::from_thunk_untyped(th), PhantomData) + } + pub(crate) fn const_sort() -> Self { + Typed(TypedInternal::Sort, PhantomData) } } |