diff options
Diffstat (limited to 'dhall/src')
| -rw-r--r-- | dhall/src/binary.rs | 4 | ||||
| -rw-r--r-- | dhall/src/normalize.rs | 46 | ||||
| -rw-r--r-- | dhall/src/typecheck.rs | 17 |
3 files changed, 38 insertions, 29 deletions
diff --git a/dhall/src/binary.rs b/dhall/src/binary.rs index 2279a51..1ab7956 100644 --- a/dhall/src/binary.rs +++ b/dhall/src/binary.rs @@ -94,14 +94,14 @@ fn cbor_value_to_dhall(data: &cbor::Value) -> Result<ParsedExpr, DecodeError> { } [U64(4), t] => { let t = cbor_value_to_dhall(&t)?; - ListLit(Some(t), vec![]) + EmptyListLit(t) } [U64(4), Null, rest..] => { let rest = rest .iter() .map(cbor_value_to_dhall) .collect::<Result<Vec<_>, _>>()?; - ListLit(None, rest) + NEListLit(rest) } [U64(5), t] => { let t = cbor_value_to_dhall(&t)?; diff --git a/dhall/src/normalize.rs b/dhall/src/normalize.rs index bf1bff5..c728dd0 100644 --- a/dhall/src/normalize.rs +++ b/dhall/src/normalize.rs @@ -57,16 +57,26 @@ where (NaturalShow, Some(NaturalLit(n)), _) => { rc(TextLit(n.to_string().into())) } - (ListLength, Some(ListLit(_, ys)), _) => rc(NaturalLit(ys.len())), - (ListHead, Some(ListLit(t, ys)), _) => { - rc(OptionalLit(t.clone(), ys.iter().cloned().next())) + (ListLength, Some(EmptyListLit(_)), _) => rc(NaturalLit(0)), + (ListLength, Some(NEListLit(ys)), _) => rc(NaturalLit(ys.len())), + (ListHead, Some(EmptyListLit(t)), _) => { + rc(OptionalLit(Some(t.clone()), None)) } - (ListLast, Some(ListLit(t, ys)), _) => { - rc(OptionalLit(t.clone(), ys.iter().cloned().last())) + (ListHead, Some(NEListLit(ys)), _) => { + rc(OptionalLit(None, ys.iter().cloned().next())) } - (ListReverse, Some(ListLit(t, ys)), _) => { - let xs = ys.iter().rev().cloned().collect(); - rc(ListLit(t.clone(), xs)) + (ListLast, Some(EmptyListLit(t)), _) => { + rc(OptionalLit(Some(t.clone()), None)) + } + (ListLast, Some(NEListLit(ys)), _) => { + rc(OptionalLit(None, ys.iter().cloned().last())) + } + (ListReverse, Some(EmptyListLit(t)), _) => { + rc(EmptyListLit(t.clone())) + } + (ListReverse, Some(NEListLit(ys)), _) => { + let ys = ys.iter().rev().cloned().collect(); + rc(NEListLit(ys)) } (ListBuild, _, [a0, g, ..]) => { loop { @@ -99,7 +109,10 @@ where break dhall_expr!((g (Optional a0)) (λ(x: a0) -> [x] : Optional a0) ([] : Optional a0)); } } - (ListFold, Some(ListLit(_, xs)), [_, _, _, cons, nil, ..]) => { + (ListFold, Some(EmptyListLit(_)), [_, _, _, _, nil, ..]) => { + Rc::clone(nil) + } + (ListFold, Some(NEListLit(xs)), [_, _, _, cons, nil, ..]) => { xs.iter().rev().fold(Rc::clone(nil), |acc, x| { let x = x.clone(); let acc = acc.clone(); @@ -233,18 +246,13 @@ where NaturalLit(x * y) } (TextAppend, TextLit(x), TextLit(y)) => TextLit(x + y), - (ListAppend, ListLit(t1, xs), ListLit(t2, ys)) => { - let t1: Option<Rc<_>> = t1.as_ref().map(Rc::clone); - let t2: Option<Rc<_>> = t2.as_ref().map(Rc::clone); - // Drop type annotation if the result is nonempty - let t = if xs.is_empty() && ys.is_empty() { - t1.or(t2) - } else { - None - }; + (ListAppend, EmptyListLit(t), EmptyListLit(_)) => EmptyListLit(Rc::clone(t)), + (ListAppend, EmptyListLit(_), _) => return y, + (ListAppend, _, EmptyListLit(_)) => return x, + (ListAppend, NEListLit(xs), NEListLit(ys)) => { let xs = xs.into_iter().cloned(); let ys = ys.into_iter().cloned(); - ListLit(t, xs.chain(ys).collect()) + NEListLit(xs.chain(ys).collect()) } (o, _, _) => BinOp(*o, x, y), }) diff --git a/dhall/src/typecheck.rs b/dhall/src/typecheck.rs index 26ab360..387327a 100644 --- a/dhall/src/typecheck.rs +++ b/dhall/src/typecheck.rs @@ -351,15 +351,16 @@ where } return Ok(ty); } - ListLit(t, xs) => { + EmptyListLit(t) => { + let s = normalized_type_with(ctx, t.clone())?; + ensure_is_type(s, InvalidListType(t.clone()))?; + let t = normalize(Rc::clone(t)); + return Ok(dhall_expr!(List t)); + } + NEListLit(xs) => { let mut iter = xs.iter().enumerate(); - let t: Rc<Expr<_, _>> = match t { - Some(t) => t.clone(), - None => { - let (_, first_x) = iter.next().unwrap(); - type_with(ctx, first_x.clone())? - } - }; + let (_, first_x) = iter.next().unwrap(); + let t = type_with(ctx, first_x.clone())?; let s = normalized_type_with(ctx, t.clone())?; ensure_is_type(s, InvalidListType(t.clone()))?; |