diff options
Diffstat (limited to 'dhall/src/phase/normalize.rs')
-rw-r--r-- | dhall/src/phase/normalize.rs | 50 |
1 files changed, 36 insertions, 14 deletions
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs index 35d32cb..395cf28 100644 --- a/dhall/src/phase/normalize.rs +++ b/dhall/src/phase/normalize.rs @@ -47,6 +47,16 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value { )), _ => Err(()), }, + (NaturalSubtract, [a, b, r..]) => { + match (&*a.as_value(), &*b.as_value()) { + (NaturalLit(a), NaturalLit(b)) => { + Ok((r, NaturalLit(if b > a { b - a } else { 0 }))) + } + (NaturalLit(0), b) => Ok((r, b.clone())), + (_, NaturalLit(0)) => Ok((r, NaturalLit(0))), + _ => Err(()), + } + } (IntegerShow, [n, r..]) => match &*n.as_value() { IntegerLit(n) => { let s = if *n < 0 { @@ -72,6 +82,17 @@ pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value { (TextShow, [v, r..]) => match &*v.as_value() { TextLit(elts) => { match elts.as_slice() { + // Empty string literal. + [] => { + // Printing InterpolatedText takes care of all the escaping + let txt: InterpolatedText<X> = + std::iter::empty().collect(); + let s = txt.to_string(); + Ok(( + r, + TextLit(vec![InterpolatedTextContents::Text(s)]), + )) + } // If there are no interpolations (invariants ensure that when there are no // interpolations, there is a single Text item) in the literal. [InterpolatedTextContents::Text(s)] => { @@ -611,7 +632,7 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> { pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { use Value::{ - BoolLit, DoubleLit, EmptyListLit, EmptyOptionalLit, IntegerLit, Lam, + AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit, Lam, NEListLit, NEOptionalLit, NaturalLit, Pi, RecordLit, RecordType, TextLit, UnionConstructor, UnionLit, UnionType, }; @@ -639,13 +660,21 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { ExprF::NaturalLit(n) => Ret::Value(NaturalLit(n)), ExprF::IntegerLit(n) => Ret::Value(IntegerLit(n)), ExprF::DoubleLit(n) => Ret::Value(DoubleLit(n)), - ExprF::OldOptionalLit(None, t) => { - Ret::Value(EmptyOptionalLit(TypeThunk::from_thunk(t))) - } - ExprF::OldOptionalLit(Some(e), _) => Ret::Value(NEOptionalLit(e)), ExprF::SomeLit(e) => Ret::Value(NEOptionalLit(e)), - ExprF::EmptyListLit(t) => { - Ret::Value(EmptyListLit(TypeThunk::from_thunk(t))) + ExprF::EmptyListLit(ref t) => { + // Check if the type is of the form `List x` + let t_borrow = t.as_value(); + match &*t_borrow { + AppliedBuiltin(Builtin::List, args) if args.len() == 1 => { + Ret::Value(EmptyListLit(TypeThunk::from_thunk( + args[0].clone(), + ))) + } + _ => { + drop(t_borrow); + Ret::Expr(expr) + } + } } ExprF::NEListLit(elts) => { Ret::Value(NEListLit(elts.into_iter().collect())) @@ -658,13 +687,6 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { .map(|(k, t)| (k, TypeThunk::from_thunk(t))) .collect(), )), - ExprF::UnionLit(l, x, kts) => Ret::Value(UnionLit( - l, - x, - kts.into_iter() - .map(|(k, t)| (k, t.map(|t| TypeThunk::from_thunk(t)))) - .collect(), - )), ExprF::UnionType(kts) => Ret::Value(UnionType( kts.into_iter() .map(|(k, t)| (k, t.map(|t| TypeThunk::from_thunk(t)))) |