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authorNadrieril2020-02-13 20:56:38 +0000
committerNadrieril2020-02-13 20:56:38 +0000
commit350d1cf7d9c114b1334b2743071b0b99ea64c1ec (patch)
treef229aefbf52a22aacddd8a5fe5149e5c654e7f1f /dhall/src
parente25b67906ce68e8726e8139c1d1855f3ab2518ce (diff)
TyExpr always carries a type
Diffstat (limited to '')
-rw-r--r--dhall/src/error/mod.rs2
-rw-r--r--dhall/src/lib.rs2
-rw-r--r--dhall/src/semantics/tck/tyexpr.rs41
-rw-r--r--dhall/src/semantics/tck/typecheck.rs112
4 files changed, 68 insertions, 89 deletions
diff --git a/dhall/src/error/mod.rs b/dhall/src/error/mod.rs
index 9cb8a41..51bd549 100644
--- a/dhall/src/error/mod.rs
+++ b/dhall/src/error/mod.rs
@@ -51,7 +51,6 @@ pub struct TypeError {
/// The specific type error
#[derive(Debug)]
pub(crate) enum TypeMessage {
- Sort,
Custom(String),
}
@@ -74,7 +73,6 @@ impl std::fmt::Display for TypeError {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
use TypeMessage::*;
let msg = match &self.message {
- Sort => format!("Type error: Unhandled error: {:?}", self.message),
Custom(s) => format!("Type error: {}", s),
};
write!(f, "{}", msg)
diff --git a/dhall/src/lib.rs b/dhall/src/lib.rs
index 2f0ed4b..ad54c9f 100644
--- a/dhall/src/lib.rs
+++ b/dhall/src/lib.rs
@@ -120,7 +120,7 @@ impl Typed {
}
pub(crate) fn get_type(&self) -> Result<Normalized, TypeError> {
- Ok(Normalized(self.0.get_type()?))
+ Ok(Normalized(self.0.ty().clone()))
}
}
diff --git a/dhall/src/semantics/tck/tyexpr.rs b/dhall/src/semantics/tck/tyexpr.rs
index dc14cd2..ac15ac5 100644
--- a/dhall/src/semantics/tck/tyexpr.rs
+++ b/dhall/src/semantics/tck/tyexpr.rs
@@ -1,4 +1,3 @@
-use crate::error::{TypeError, TypeMessage};
use crate::semantics::{Hir, HirKind, NzEnv, TyEnv, Value};
use crate::syntax::{Const, Span};
use crate::{NormalizedExpr, ToExprOptions};
@@ -6,39 +5,36 @@ use crate::{NormalizedExpr, ToExprOptions};
pub(crate) type Type = Value;
// A hir expression plus its inferred type.
-#[derive(Clone)]
+#[derive(Debug, Clone)]
pub(crate) struct TyExpr {
hir: Hir,
- ty: Option<Type>,
+ ty: Type,
}
impl TyExpr {
- pub fn new(kind: HirKind, ty: Option<Type>, span: Span) -> Self {
+ pub fn new(kind: HirKind, ty: Type, span: Span) -> Self {
TyExpr {
hir: Hir::new(kind, span),
ty,
}
}
- pub fn kind(&self) -> &HirKind {
- self.hir.kind()
- }
pub fn span(&self) -> Span {
self.as_hir().span()
}
- pub fn get_type(&self) -> Result<Type, TypeError> {
- match &self.ty {
- Some(t) => Ok(t.clone()),
- None => Err(TypeError::new(TypeMessage::Sort)),
- }
+ pub fn ty(&self) -> &Type {
+ &self.ty
}
- pub fn get_type_tyexpr(&self, env: &TyEnv) -> Result<TyExpr, TypeError> {
- Ok(self.get_type()?.to_hir(env.as_varenv()).typecheck(env)?)
+ pub fn get_type_tyexpr(&self, env: &TyEnv) -> TyExpr {
+ self.ty()
+ .to_hir(env.as_varenv())
+ .typecheck(env)
+ .expect("Internal type error")
}
/// Get the kind (the type of the type) of this value
// TODO: avoid recomputing so much
- pub fn get_kind(&self, env: &TyEnv) -> Result<Option<Const>, TypeError> {
- Ok(self.get_type_tyexpr(env)?.get_type()?.as_const())
+ pub fn get_kind(&self, env: &TyEnv) -> Option<Const> {
+ self.get_type_tyexpr(env).ty().as_const()
}
pub fn to_hir(&self) -> Hir {
@@ -68,16 +64,3 @@ impl TyExpr {
val
}
}
-
-impl std::fmt::Debug for TyExpr {
- fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
- let mut x = fmt.debug_struct("TyExpr");
- x.field("kind", self.kind());
- if let Some(ty) = self.ty.as_ref() {
- x.field("type", &ty);
- } else {
- x.field("type", &None::<()>);
- }
- x.finish()
- }
-}
diff --git a/dhall/src/semantics/tck/typecheck.rs b/dhall/src/semantics/tck/typecheck.rs
index a4ab31f..b3c9353 100644
--- a/dhall/src/semantics/tck/typecheck.rs
+++ b/dhall/src/semantics/tck/typecheck.rs
@@ -53,24 +53,24 @@ fn type_one_layer(
ExprKind::Lam(binder, annot, body) => {
let body_ty = body.get_type_tyexpr(
&env.insert_type(&binder.clone(), annot.eval(env)),
- )?;
+ );
let pi_ekind = ExprKind::Pi(binder.clone(), annot.clone(), body_ty);
type_one_layer(env, pi_ekind, None, Span::Artificial)?.eval(env)
}
ExprKind::Pi(_, annot, body) => {
- let ks = match annot.get_type()?.as_const() {
+ let ks = match annot.ty().as_const() {
Some(k) => k,
_ => {
return mkerr(
ErrorBuilder::new(format!(
"Invalid input type: `{}`",
- annot.get_type()?.to_expr_tyenv(env),
+ annot.ty().to_expr_tyenv(env),
))
.span_err(
annot.span(),
format!(
"this has type: `{}`",
- annot.get_type()?.to_expr_tyenv(env)
+ annot.ty().to_expr_tyenv(env)
),
)
.help(format!(
@@ -81,14 +81,14 @@ fn type_one_layer(
);
}
};
- let kt = match body.get_type()?.as_const() {
+ let kt = match body.ty().as_const() {
Some(k) => k,
_ => return span_err("Invalid output type"),
};
Value::from_const(function_check(ks, kt))
}
- ExprKind::Let(_, _, _, body) => body.get_type()?,
+ ExprKind::Let(_, _, _, body) => body.ty().clone(),
ExprKind::Const(Const::Type) => Value::from_const(Const::Kind),
ExprKind::Const(Const::Kind) => Value::from_const(Const::Sort),
@@ -112,7 +112,7 @@ fn type_one_layer(
for contents in interpolated.iter() {
use InterpolatedTextContents::Expr;
if let Expr(x) = contents {
- if x.get_type()? != text_type {
+ if *x.ty() != text_type {
return span_err("InvalidTextInterpolation");
}
}
@@ -121,7 +121,7 @@ fn type_one_layer(
}
ExprKind::EmptyListLit(t) => {
let t = t.eval(env);
- match &*t.kind() {
+ match t.kind() {
ValueKind::AppliedBuiltin(BuiltinClosure {
b: Builtin::List,
args,
@@ -135,23 +135,23 @@ fn type_one_layer(
let mut iter = xs.iter();
let x = iter.next().unwrap();
for y in iter {
- if x.get_type()? != y.get_type()? {
+ if x.ty() != y.ty() {
return span_err("InvalidListElement");
}
}
- if x.get_kind(env)? != Some(Const::Type) {
+ if x.get_kind(env) != Some(Const::Type) {
return span_err("InvalidListType");
}
- let t = x.get_type()?;
+ let t = x.ty().clone();
Value::from_builtin(Builtin::List).app(t)
}
ExprKind::SomeLit(x) => {
- if x.get_kind(env)? != Some(Const::Type) {
+ if x.get_kind(env) != Some(Const::Type) {
return span_err("InvalidOptionalType");
}
- let t = x.get_type()?;
+ let t = x.ty().clone();
Value::from_builtin(Builtin::Optional).app(t)
}
ExprKind::RecordLit(kvs) => {
@@ -163,11 +163,11 @@ fn type_one_layer(
Entry::Occupied(_) => {
return span_err("RecordTypeDuplicateField")
}
- Entry::Vacant(e) => e.insert(v.get_type()?),
+ Entry::Vacant(e) => e.insert(v.ty().clone()),
};
// Check that the fields have a valid kind
- match v.get_kind(env)? {
+ match v.get_kind(env) {
Some(_) => {}
None => return span_err("InvalidFieldType"),
}
@@ -191,7 +191,7 @@ fn type_one_layer(
};
// Check the type is a Const and compute final type
- match t.get_type()?.as_const() {
+ match t.ty().as_const() {
Some(c) => k = max(k, c),
None => return span_err("InvalidFieldType"),
}
@@ -206,7 +206,7 @@ fn type_one_layer(
let mut k = None;
for (x, t) in kts {
if let Some(t) = t {
- match (k, t.get_type()?.as_const()) {
+ match (k, t.ty().as_const()) {
(None, Some(k2)) => k = Some(k2),
(Some(k1), Some(k2)) if k1 == k2 => {}
_ => return span_err("InvalidFieldType"),
@@ -227,12 +227,12 @@ fn type_one_layer(
Value::from_const(k)
}
ExprKind::Field(scrut, x) => {
- match &*scrut.get_type()?.kind() {
+ match scrut.ty().kind() {
ValueKind::RecordType(kts) => match kts.get(&x) {
Some(tth) => tth.clone(),
None => return span_err("MissingRecordField"),
},
- // TODO: branch here only when scrut.get_type() is a Const
+ // TODO: branch here only when scrut.ty() is a Const
_ => {
let scrut_nf = scrut.eval(env);
match scrut_nf.kind() {
@@ -255,7 +255,7 @@ fn type_one_layer(
}
ExprKind::Assert(t) => {
let t = t.eval(env);
- match &*t.kind() {
+ match t.kind() {
ValueKind::Equivalence(x, y) if x == y => {}
ValueKind::Equivalence(..) => {
return span_err("AssertMismatch")
@@ -265,9 +265,9 @@ fn type_one_layer(
t
}
ExprKind::App(f, arg) => {
- match f.get_type()?.kind() {
+ match f.ty().kind() {
ValueKind::PiClosure { annot, closure, .. } => {
- if arg.get_type()? != *annot {
+ if arg.ty() != annot {
return mkerr(
ErrorBuilder::new(format!(
"wrong type of function argument"
@@ -283,13 +283,13 @@ fn type_one_layer(
arg.span(),
format!(
"but this has type: {}",
- arg.get_type()?.to_expr_tyenv(env),
+ arg.ty().to_expr_tyenv(env),
),
)
.note(format!(
"expected type `{}`\n found type `{}`",
annot.to_expr_tyenv(env),
- arg.get_type()?.to_expr_tyenv(env),
+ arg.ty().to_expr_tyenv(env),
))
.format(),
);
@@ -301,7 +301,7 @@ fn type_one_layer(
_ => return mkerr(
ErrorBuilder::new(format!(
"expected function, found `{}`",
- f.get_type()?.to_expr_tyenv(env)
+ f.ty().to_expr_tyenv(env)
))
.span_err(
f.span(),
@@ -312,21 +312,21 @@ fn type_one_layer(
}
}
ExprKind::BoolIf(x, y, z) => {
- if *x.get_type()?.kind() != ValueKind::from_builtin(Builtin::Bool) {
+ if *x.ty().kind() != ValueKind::from_builtin(Builtin::Bool) {
return span_err("InvalidPredicate");
}
- if y.get_kind(env)? != Some(Const::Type) {
+ if y.get_kind(env) != Some(Const::Type) {
return span_err("IfBranchMustBeTerm");
}
- if y.get_type()? != z.get_type()? {
+ if y.ty() != z.ty() {
return span_err("IfBranchMismatch");
}
- y.get_type()?
+ y.ty().clone()
}
ExprKind::BinOp(BinOp::RightBiasedRecordMerge, x, y) => {
- let x_type = x.get_type()?;
- let y_type = y.get_type()?;
+ let x_type = x.ty();
+ let y_type = y.ty();
// Extract the LHS record type
let kts_x = match x_type.kind() {
@@ -350,8 +350,8 @@ fn type_one_layer(
ExprKind::BinOp(BinOp::RecursiveRecordMerge, x, y) => {
let ekind = ExprKind::BinOp(
BinOp::RecursiveRecordTypeMerge,
- x.get_type_tyexpr(env)?,
- y.get_type_tyexpr(env)?,
+ x.get_type_tyexpr(env),
+ y.get_type_tyexpr(env),
);
type_one_layer(env, ekind, None, span.clone())?.eval(env)
}
@@ -390,13 +390,12 @@ fn type_one_layer(
check_rectymerge(&span, env, x.eval(env), y.eval(env))?;
// A RecordType's type is always a const
- let xk = x.get_type()?.as_const().unwrap();
- let yk = y.get_type()?.as_const().unwrap();
+ let xk = x.ty().as_const().unwrap();
+ let yk = y.ty().as_const().unwrap();
Value::from_const(max(xk, yk))
}
ExprKind::BinOp(BinOp::ListAppend, l, r) => {
- let l_ty = l.get_type()?;
- match &*l_ty.kind() {
+ match l.ty().kind() {
ValueKind::AppliedBuiltin(BuiltinClosure {
b: Builtin::List,
..
@@ -404,17 +403,17 @@ fn type_one_layer(
_ => return span_err("BinOpTypeMismatch"),
}
- if l_ty != r.get_type()? {
+ if l.ty() != r.ty() {
return span_err("BinOpTypeMismatch");
}
- l_ty
+ l.ty().clone()
}
ExprKind::BinOp(BinOp::Equivalence, l, r) => {
- if l.get_type()? != r.get_type()? {
+ if l.ty() != r.ty() {
return span_err("EquivalenceTypeMismatch");
}
- if l.get_kind(env)? != Some(Const::Type) {
+ if l.get_kind(env) != Some(Const::Type) {
return span_err("EquivalenceArgumentsMustBeTerms");
}
@@ -436,24 +435,24 @@ fn type_one_layer(
BinOp::ImportAlt => unreachable!("ImportAlt leftover in tck"),
});
- if l.get_type()? != t {
+ if *l.ty() != t {
return span_err("BinOpTypeMismatch");
}
- if r.get_type()? != t {
+ if *r.ty() != t {
return span_err("BinOpTypeMismatch");
}
t
}
ExprKind::Merge(record, union, type_annot) => {
- let record_type = record.get_type()?;
+ let record_type = record.ty();
let handlers = match record_type.kind() {
ValueKind::RecordType(kts) => kts,
_ => return span_err("Merge1ArgMustBeRecord"),
};
- let union_type = union.get_type()?;
+ let union_type = union.ty();
let variants = match union_type.kind() {
ValueKind::UnionType(kts) => Cow::Borrowed(kts),
ValueKind::AppliedBuiltin(BuiltinClosure {
@@ -583,10 +582,10 @@ fn type_one_layer(
}
}
ExprKind::ToMap(record, annot) => {
- if record.get_kind(env)? != Some(Const::Type) {
+ if record.get_kind(env) != Some(Const::Type) {
return span_err("`toMap` only accepts records of type `Type`");
}
- let record_t = record.get_type()?;
+ let record_t = record.ty();
let kts = match record_t.kind() {
ValueKind::RecordType(kts) => kts,
_ => {
@@ -656,7 +655,7 @@ fn type_one_layer(
}
}
ExprKind::Projection(record, labels) => {
- let record_type = record.get_type()?;
+ let record_type = record.ty();
let kts = match record_type.kind() {
ValueKind::RecordType(kts) => kts,
_ => return span_err("ProjectionMustBeRecord"),
@@ -681,7 +680,7 @@ fn type_one_layer(
Value::from_kind(ValueKind::RecordType(new_kts))
}
ExprKind::ProjectionByExpr(record, selection) => {
- let record_type = record.get_type()?;
+ let record_type = record.ty();
let rec_kts = match record_type.kind() {
ValueKind::RecordType(kts) => kts,
_ => return span_err("ProjectionMustBeRecord"),
@@ -742,9 +741,10 @@ fn type_one_layer(
}
}
+ // TODO: avoid retraversing
Ok(TyExpr::new(
HirKind::Expr(ekind.map_ref(|tye| tye.to_hir())),
- Some(ty),
+ ty,
span,
))
}
@@ -757,11 +757,9 @@ pub(crate) fn type_with(
annot: Option<Type>,
) -> Result<TyExpr, TypeError> {
match hir.kind() {
- HirKind::Var(var) => Ok(TyExpr::new(
- HirKind::Var(*var),
- Some(env.lookup(var)),
- hir.span(),
- )),
+ HirKind::Var(var) => {
+ Ok(TyExpr::new(HirKind::Var(*var), env.lookup(var), hir.span()))
+ }
HirKind::Expr(ExprKind::Var(_)) => {
unreachable!("Hir should contain no unresolved variables")
}
@@ -800,9 +798,9 @@ pub(crate) fn type_with(
None
};
let val = type_with(env, &val, val_annot)?;
- let val_ty = val.get_type()?;
let val_nf = val.eval(env);
- let body_env = env.insert_value(&binder, val_nf, val_ty);
+ let body_env =
+ env.insert_value(&binder, val_nf, val.ty().clone());
let body = type_with(&body_env, body, None)?;
ExprKind::Let(binder.clone(), None, val, body)
}