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-rw-r--r--dhall/src/expr.rs21
-rw-r--r--dhall/src/lib.rs3
-rw-r--r--dhall/src/traits.rs109
-rw-r--r--dhall/src/typecheck.rs21
4 files changed, 111 insertions, 43 deletions
diff --git a/dhall/src/expr.rs b/dhall/src/expr.rs
index 7baf628..5ff097b 100644
--- a/dhall/src/expr.rs
+++ b/dhall/src/expr.rs
@@ -36,6 +36,11 @@ derive_other_traits!(Typed);
pub struct Normalized(pub(crate) SubExpr<X, X>, pub(crate) Type);
derive_other_traits!(Normalized);
+/// An expression of type `Type` (like `Bool` or `Natural -> Text`, but not `Type`)
+#[derive(Debug, Clone, Eq)]
+pub struct SimpleType(pub(crate) SubExpr<X, X>);
+derive_other_traits!(SimpleType);
+
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Type(pub(crate) TypeInternal);
@@ -44,3 +49,19 @@ pub(crate) enum TypeInternal {
Expr(Box<Normalized>),
Untyped,
}
+
+// Exposed for the macros
+#[doc(hidden)]
+impl From<SimpleType> for SubExpr<X, X> {
+ fn from(x: SimpleType) -> SubExpr<X, X> {
+ x.0
+ }
+}
+
+// Exposed for the macros
+#[doc(hidden)]
+impl From<SubExpr<X, X>> for SimpleType {
+ fn from(x: SubExpr<X, X>) -> SimpleType {
+ SimpleType(x)
+ }
+}
diff --git a/dhall/src/lib.rs b/dhall/src/lib.rs
index 5c5a641..3bfc46f 100644
--- a/dhall/src/lib.rs
+++ b/dhall/src/lib.rs
@@ -21,6 +21,7 @@ mod imports;
mod normalize;
mod traits;
mod typecheck;
+pub use crate::traits::SimpleStaticType;
pub use crate::traits::StaticType;
-pub use dhall_generator::StaticType;
+pub use dhall_generator::SimpleStaticType;
pub mod expr;
diff --git a/dhall/src/traits.rs b/dhall/src/traits.rs
index 64e07d9..4925457 100644
--- a/dhall/src/traits.rs
+++ b/dhall/src/traits.rs
@@ -1,77 +1,108 @@
+use crate::expr::*;
use dhall_core::*;
use dhall_generator::*;
+use std::borrow::Cow;
#[derive(Debug, Clone)]
pub enum ConversionError {}
pub trait StaticType {
- fn get_type() -> DhallExpr;
- // fn as_dhall(&self) -> DhallExpr;
- // fn from_dhall(e: DhallExpr) -> Result<Self, DhallConversionError>;
+ fn get_static_type() -> Type;
}
-impl StaticType for bool {
- fn get_type() -> DhallExpr {
- dhall_expr!(Bool)
+/// Trait for rust types that can be represented in dhall in
+/// a single way, independent of the value. A typical example is `Option<bool>`,
+/// represented by the dhall expression `Optional Bool`. A typical counterexample
+/// is `HashMap<Text, bool>` because dhall cannot represent records with a
+/// variable number of fields.
+pub trait SimpleStaticType {
+ fn get_simple_static_type() -> SimpleType;
+}
+
+fn mktype(x: SubExpr<X, X>) -> SimpleType {
+ SimpleType(x)
+}
+
+impl<T: SimpleStaticType> StaticType for T {
+ fn get_static_type() -> Type {
+ crate::expr::Normalized(
+ T::get_simple_static_type().into(),
+ Type::const_type(),
+ )
+ .into_type()
+ }
+}
+
+impl StaticType for SimpleType {
+ fn get_static_type() -> Type {
+ Type::const_type()
+ }
+}
+
+impl SimpleStaticType for bool {
+ fn get_simple_static_type() -> SimpleType {
+ mktype(dhall_expr!(Bool))
}
}
-impl StaticType for Natural {
- fn get_type() -> DhallExpr {
- dhall_expr!(Natural)
+impl SimpleStaticType for Natural {
+ fn get_simple_static_type() -> SimpleType {
+ mktype(dhall_expr!(Natural))
}
}
-impl StaticType for Integer {
- fn get_type() -> DhallExpr {
- dhall_expr!(Integer)
+impl SimpleStaticType for Integer {
+ fn get_simple_static_type() -> SimpleType {
+ mktype(dhall_expr!(Integer))
}
}
-impl StaticType for String {
- fn get_type() -> DhallExpr {
- dhall_expr!(Text)
+impl SimpleStaticType for String {
+ fn get_simple_static_type() -> SimpleType {
+ mktype(dhall_expr!(Text))
}
}
-impl<A: StaticType, B: StaticType> StaticType for (A, B) {
- fn get_type() -> DhallExpr {
- let ta = A::get_type();
- let tb = B::get_type();
- dhall_expr!({ _1: ta, _2: tb })
+impl<A: SimpleStaticType, B: SimpleStaticType> SimpleStaticType for (A, B) {
+ fn get_simple_static_type() -> SimpleType {
+ let ta: SubExpr<_, _> = A::get_simple_static_type().into();
+ let tb: SubExpr<_, _> = B::get_simple_static_type().into();
+ mktype(dhall_expr!({ _1: ta, _2: tb }))
}
}
-impl<T: StaticType> StaticType for Option<T> {
- fn get_type() -> DhallExpr {
- let t = T::get_type();
- dhall_expr!(Optional t)
+impl<T: SimpleStaticType> SimpleStaticType for Option<T> {
+ fn get_simple_static_type() -> SimpleType {
+ let t: SubExpr<_, _> = T::get_simple_static_type().into();
+ mktype(dhall_expr!(Optional t))
}
}
-impl<T: StaticType> StaticType for Vec<T> {
- fn get_type() -> DhallExpr {
- let t = T::get_type();
- dhall_expr!(List t)
+impl<T: SimpleStaticType> SimpleStaticType for Vec<T> {
+ fn get_simple_static_type() -> SimpleType {
+ let t: SubExpr<_, _> = T::get_simple_static_type().into();
+ mktype(dhall_expr!(List t))
}
}
-impl<'a, T: StaticType> StaticType for &'a T {
- fn get_type() -> DhallExpr {
- T::get_type()
+impl<'a, T: SimpleStaticType> SimpleStaticType for &'a T {
+ fn get_simple_static_type() -> SimpleType {
+ T::get_simple_static_type()
}
}
-impl<T> StaticType for std::marker::PhantomData<T> {
- fn get_type() -> DhallExpr {
- dhall_expr!({})
+impl<T> SimpleStaticType for std::marker::PhantomData<T> {
+ fn get_simple_static_type() -> SimpleType {
+ mktype(dhall_expr!({}))
}
}
-impl<T: StaticType, E: StaticType> StaticType for Result<T, E> {
- fn get_type() -> DhallExpr {
- let tt = T::get_type();
- let te = E::get_type();
- dhall_expr!(< Ok: tt | Err: te>)
+impl<T: SimpleStaticType, E: SimpleStaticType> SimpleStaticType
+ for std::result::Result<T, E>
+{
+ fn get_simple_static_type() -> SimpleType {
+ let tt: SubExpr<_, _> = T::get_simple_static_type().into();
+ let te: SubExpr<_, _> = E::get_simple_static_type().into();
+ mktype(dhall_expr!(< Ok: tt | Err: te>))
}
}
diff --git a/dhall/src/typecheck.rs b/dhall/src/typecheck.rs
index 998d3ca..f51f1b6 100644
--- a/dhall/src/typecheck.rs
+++ b/dhall/src/typecheck.rs
@@ -42,7 +42,7 @@ impl Normalized {
&self.0
}
#[inline(always)]
- fn into_expr(self) -> SubExpr<X, X> {
+ pub(crate) fn into_expr(self) -> SubExpr<X, X> {
self.0
}
#[inline(always)]
@@ -50,7 +50,7 @@ impl Normalized {
&self.1
}
#[inline(always)]
- fn into_type(self) -> Type {
+ pub(crate) fn into_type(self) -> Type {
crate::expr::Type(TypeInternal::Expr(Box::new(self)))
}
// Expose the outermost constructor
@@ -78,7 +78,7 @@ impl Type {
}
}
#[inline(always)]
- fn into_normalized(self) -> Result<Normalized, TypeError<X>> {
+ pub(crate) fn into_normalized(self) -> Result<Normalized, TypeError<X>> {
use TypeInternal::*;
match self.0 {
Expr(e) => Ok(*e),
@@ -110,6 +110,21 @@ impl Type {
Untyped => Untyped,
})
}
+
+ #[inline(always)]
+ pub fn const_sort() -> Self {
+ Normalized(rc(ExprF::Const(Const::Sort)), UNTYPE).into_type()
+ }
+ #[inline(always)]
+ pub fn const_kind() -> Self {
+ Normalized(rc(ExprF::Const(Const::Kind)), Type::const_sort())
+ .into_type()
+ }
+ #[inline(always)]
+ pub fn const_type() -> Self {
+ Normalized(rc(ExprF::Const(Const::Type)), Type::const_kind())
+ .into_type()
+ }
}
const UNTYPE: Type = Type(TypeInternal::Untyped);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-29 09:15:44 +0000