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path: root/dhall/src/semantics/tck/typecheck.rs
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Diffstat (limited to 'dhall/src/semantics/tck/typecheck.rs')
-rw-r--r--dhall/src/semantics/tck/typecheck.rs183
1 files changed, 155 insertions, 28 deletions
diff --git a/dhall/src/semantics/tck/typecheck.rs b/dhall/src/semantics/tck/typecheck.rs
index c3c589b..6817712 100644
--- a/dhall/src/semantics/tck/typecheck.rs
+++ b/dhall/src/semantics/tck/typecheck.rs
@@ -51,9 +51,9 @@ fn mkerr<T, S: ToString>(x: S) -> Result<T, TypeError> {
/// layer.
fn type_one_layer(
env: &TyEnv,
- kind: &ExprKind<TyExpr, Normalized>,
+ ekind: ExprKind<TyExpr, Normalized>,
span: Span,
-) -> Result<Type, TypeError> {
+) -> Result<TyExpr, TypeError> {
let span_err = |msg: &str| {
mkerr(
ErrorBuilder::new(msg.to_string())
@@ -62,7 +62,7 @@ fn type_one_layer(
)
};
- Ok(match kind {
+ let ty = match &ekind {
ExprKind::Import(..) => unreachable!(
"There should remain no imports in a resolved expression"
),
@@ -74,13 +74,8 @@ fn type_one_layer(
let body_ty = body.get_type()?;
let body_ty = body_ty.to_tyexpr(env.as_varenv().insert());
let pi_ekind = ExprKind::Pi(binder.clone(), annot.clone(), body_ty);
- let pi_ty = type_one_layer(env, &pi_ekind, Span::Artificial)?;
- let ty = TyExpr::new(
- TyExprKind::Expr(pi_ekind),
- Some(pi_ty),
- Span::Artificial,
- );
- ty.eval(env.as_nzenv())
+ type_one_layer(env, pi_ekind, Span::Artificial)?
+ .eval(env.as_nzenv())
}
ExprKind::Pi(_, annot, body) => {
let ks = match annot.get_type()?.as_const() {
@@ -187,7 +182,7 @@ fn type_one_layer(
}
let ty = type_of_recordtype(
- span,
+ span.clone(),
kts.iter()
.map(|(_, t)| Cow::Owned(t.to_tyexpr(env.as_varenv()))),
)?;
@@ -206,7 +201,10 @@ fn type_one_layer(
};
}
- type_of_recordtype(span, kts.iter().map(|(_, t)| Cow::Borrowed(t)))?
+ type_of_recordtype(
+ span.clone(),
+ kts.iter().map(|(_, t)| Cow::Borrowed(t)),
+ )?
}
ExprKind::UnionType(kts) => {
use std::collections::hash_map::Entry;
@@ -389,7 +387,7 @@ fn type_one_layer(
// Construct the final record type
let ty = type_of_recordtype(
- span,
+ span.clone(),
kts.iter()
.map(|(_, t)| Cow::Owned(t.to_tyexpr(env.as_varenv()))),
)?;
@@ -401,9 +399,7 @@ fn type_one_layer(
x.get_type()?.to_tyexpr(env.as_varenv()),
y.get_type()?.to_tyexpr(env.as_varenv()),
);
- let ty = type_one_layer(env, &ekind, Span::Artificial)?;
- TyExpr::new(TyExprKind::Expr(ekind), Some(ty), Span::Artificial)
- .eval(env.as_nzenv())
+ type_one_layer(env, ekind, Span::Artificial)?.eval(env.as_nzenv())
}
ExprKind::BinOp(BinOp::RecursiveRecordTypeMerge, x, y) => {
let x_val = x.eval(env.as_nzenv());
@@ -420,7 +416,7 @@ fn type_one_layer(
if let Some(ty) = kts_y.get(k) {
type_one_layer(
env,
- &ExprKind::BinOp(
+ ExprKind::BinOp(
BinOp::RecursiveRecordTypeMerge,
tx.to_tyexpr(env.as_varenv()),
ty.to_tyexpr(env.as_varenv()),
@@ -547,9 +543,14 @@ fn type_one_layer(
);
}
- closure.remove_binder().or_else(|()| {
- span_err("MergeReturnTypeIsDependent")
- })?
+ match closure.remove_binder() {
+ Ok(v) => v,
+ Err(()) => {
+ return span_err(
+ "MergeReturnTypeIsDependent",
+ )
+ }
+ }
}
_ => {
return mkerr(
@@ -619,7 +620,85 @@ fn type_one_layer(
(None, None) => return span_err("MergeEmptyNeedsAnnotation"),
}
}
- ExprKind::ToMap(_, _) => unimplemented!("toMap"),
+ ExprKind::ToMap(record, annot) => {
+ let record_t = record.get_type()?;
+ let kts = match record_t.kind() {
+ ValueKind::RecordType(kts) => kts,
+ _ => {
+ return span_err("The argument to `toMap` must be a record")
+ }
+ };
+
+ if kts.is_empty() {
+ let annot = if let Some(annot) = annot {
+ annot
+ } else {
+ return span_err(
+ "`toMap` applied to an empty record requires a type \
+ annotation",
+ );
+ };
+ let annot_val = annot.eval(env.as_nzenv());
+
+ let err_msg = "The type of `toMap x` must be of the form \
+ `List { mapKey : Text, mapValue : T }`";
+ let arg = match annot_val.kind() {
+ ValueKind::AppliedBuiltin(BuiltinClosure {
+ b: Builtin::List,
+ args,
+ ..
+ }) if args.len() == 1 => &args[0],
+ _ => return span_err(err_msg),
+ };
+ let kts = match arg.kind() {
+ ValueKind::RecordType(kts) => kts,
+ _ => return span_err(err_msg),
+ };
+ if kts.len() != 2 {
+ return span_err(err_msg);
+ }
+ match kts.get(&"mapKey".into()) {
+ Some(t) if *t == Value::from_builtin(Builtin::Text) => {}
+ _ => return span_err(err_msg),
+ }
+ match kts.get(&"mapValue".into()) {
+ Some(_) => {}
+ None => return span_err(err_msg),
+ }
+ annot_val
+ } else {
+ let entry_type = kts.iter().next().unwrap().1.clone();
+ if entry_type.get_type()?.as_const() != Some(Const::Type) {
+ return span_err(
+ "`toMap` only accepts records of type `Type`",
+ );
+ }
+ for (_, t) in kts.iter() {
+ if *t != entry_type {
+ return span_err(
+ "Every field of the record must have the same type",
+ );
+ }
+ }
+
+ let mut kts = HashMap::new();
+ kts.insert("mapKey".into(), Value::from_builtin(Builtin::Text));
+ kts.insert("mapValue".into(), entry_type);
+ let output_type = Value::from_builtin(Builtin::List).app(
+ Value::from_kind_and_type(
+ ValueKind::RecordType(kts),
+ Value::from_const(Const::Type),
+ ),
+ );
+ if let Some(annot) = annot {
+ let annot_val = annot.eval(env.as_nzenv());
+ if output_type != annot_val {
+ return span_err("Annotation mismatch");
+ }
+ }
+ output_type
+ }
+ }
ExprKind::Projection(record, labels) => {
let record_type = record.get_type()?;
let kts = match record_type.kind() {
@@ -648,11 +727,61 @@ fn type_one_layer(
record_type.get_type()?,
)
}
- ExprKind::ProjectionByExpr(_, _) => {
- unimplemented!("selection by expression")
+ ExprKind::ProjectionByExpr(record, selection) => {
+ let record_type = record.get_type()?;
+ let rec_kts = match record_type.kind() {
+ ValueKind::RecordType(kts) => kts,
+ _ => return span_err("ProjectionMustBeRecord"),
+ };
+
+ let selection_val = selection.eval(env.as_nzenv());
+ let sel_kts = match selection_val.kind() {
+ ValueKind::RecordType(kts) => kts,
+ _ => return span_err("ProjectionByExprTakesRecordType"),
+ };
+
+ for (l, sel_ty) in sel_kts {
+ match rec_kts.get(l) {
+ Some(rec_ty) => {
+ if rec_ty != sel_ty {
+ return span_err("ProjectionWrongType");
+ }
+ }
+ None => return span_err("ProjectionMissingEntry"),
+ }
+ }
+
+ selection_val
+ }
+ ExprKind::Completion(ty, compl) => {
+ let ty_field_default = type_one_layer(
+ env,
+ ExprKind::Field(ty.clone(), "default".into()),
+ span.clone(),
+ )?;
+ let ty_field_type = type_one_layer(
+ env,
+ ExprKind::Field(ty.clone(), "Type".into()),
+ span.clone(),
+ )?;
+ let merge = type_one_layer(
+ env,
+ ExprKind::BinOp(
+ BinOp::RightBiasedRecordMerge,
+ ty_field_default,
+ compl.clone(),
+ ),
+ span.clone(),
+ )?;
+ return type_one_layer(
+ env,
+ ExprKind::Annot(merge, ty_field_type),
+ span.clone(),
+ );
}
- ExprKind::Completion(_, _) => unimplemented!("record completion"),
- })
+ };
+
+ Ok(TyExpr::new(TyExprKind::Expr(ekind), Some(ty), span))
}
/// `type_with` typechecks an expressio in the provided environment.
@@ -708,9 +837,7 @@ pub(crate) fn type_with(
}
_ => ekind.traverse_ref(|e| type_with(env, e))?,
};
-
- let ty = type_one_layer(env, &ekind, expr.span())?;
- (TyExprKind::Expr(ekind), Some(ty))
+ return type_one_layer(env, ekind, expr.span());
}
};
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-07 15:56:56 +0000