From 472a06dda81168e954e6a02c91bfcf57c6ae7b25 Mon Sep 17 00:00:00 2001 From: Nadrieril Date: Fri, 3 May 2019 14:46:28 +0200 Subject: Apply builtin arguments lazily --- dhall/src/normalize.rs | 308 ++++++++++++++++++++++++++----------------------- 1 file changed, 165 insertions(+), 143 deletions(-) (limited to 'dhall/src') diff --git a/dhall/src/normalize.rs b/dhall/src/normalize.rs index 5749989..1c90c77 100644 --- a/dhall/src/normalize.rs +++ b/dhall/src/normalize.rs @@ -59,190 +59,191 @@ impl<'a> Typed<'a> { } } -fn apply_builtin(b: Builtin, args: Vec) -> Value { +fn apply_builtin(b: Builtin, args: Vec) -> Value { use dhall_core::Builtin::*; use Value::*; - let ret = match b { - OptionalNone => improved_slice_patterns::match_vec!(args; - [t] => EmptyOptionalLit(TypeThunk::from_whnf(t)), - ), - NaturalIsZero => improved_slice_patterns::match_vec!(args; - [NaturalLit(n)] => BoolLit(n == 0), - ), - NaturalEven => improved_slice_patterns::match_vec!(args; - [NaturalLit(n)] => BoolLit(n % 2 == 0), - ), - NaturalOdd => improved_slice_patterns::match_vec!(args; - [NaturalLit(n)] => BoolLit(n % 2 != 0), - ), - NaturalToInteger => improved_slice_patterns::match_vec!(args; - [NaturalLit(n)] => IntegerLit(n as isize), - ), - NaturalShow => improved_slice_patterns::match_vec!(args; - [NaturalLit(n)] => { - TextLit(vec![InterpolatedTextContents::Text(n.to_string())]) - } - ), - ListLength => improved_slice_patterns::match_vec!(args; - [_, EmptyListLit(_)] => NaturalLit(0), - [_, NEListLit(xs)] => NaturalLit(xs.len()), - ), - ListHead => improved_slice_patterns::match_vec!(args; - [_, EmptyListLit(n)] => EmptyOptionalLit(n), - [_, NEListLit(xs)] => { - NEOptionalLit(xs.into_iter().next().unwrap()) + // Return Ok((unconsumed args, returned value)), or Err(()) if value could not be produced. + let ret = match (b, args.as_slice()) { + (OptionalNone, [t, r..]) => { + Ok((r, EmptyOptionalLit(TypeThunk::from_thunk(t.clone())))) + } + (NaturalIsZero, [n, r..]) => match &*n.as_value() { + NaturalLit(n) => Ok((r, BoolLit(*n == 0))), + _ => Err(()), + }, + (NaturalEven, [n, r..]) => match &*n.as_value() { + NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0))), + _ => Err(()), + }, + (NaturalOdd, [n, r..]) => match &*n.as_value() { + NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0))), + _ => Err(()), + }, + (NaturalToInteger, [n, r..]) => match &*n.as_value() { + NaturalLit(n) => Ok((r, IntegerLit(*n as isize))), + _ => Err(()), + }, + (NaturalShow, [n, r..]) => match &*n.as_value() { + NaturalLit(n) => Ok(( + r, + TextLit(vec![InterpolatedTextContents::Text(n.to_string())]), + )), + _ => Err(()), + }, + (ListLength, [_, l, r..]) => match &*l.as_value() { + EmptyListLit(_) => Ok((r, NaturalLit(0))), + NEListLit(xs) => Ok((r, NaturalLit(xs.len()))), + _ => Err(()), + }, + (ListHead, [_, l, r..]) => match &*l.as_value() { + EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()))), + NEListLit(xs) => { + Ok((r, NEOptionalLit(xs.iter().next().unwrap().clone()))) } - ), - ListLast => improved_slice_patterns::match_vec!(args; - [_, EmptyListLit(n)] => EmptyOptionalLit(n), - [_, NEListLit(xs)] => { - NEOptionalLit(xs.into_iter().rev().next().unwrap()) + _ => Err(()), + }, + (ListLast, [_, l, r..]) => match &*l.as_value() { + EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()))), + NEListLit(xs) => { + Ok((r, NEOptionalLit(xs.iter().rev().next().unwrap().clone()))) } - ), - ListReverse => improved_slice_patterns::match_vec!(args; - [_, EmptyListLit(n)] => EmptyListLit(n), - [_, NEListLit(xs)] => { - let mut xs = xs; - xs.reverse(); - NEListLit(xs) + _ => Err(()), + }, + (ListReverse, [_, l, r..]) => match &*l.as_value() { + EmptyListLit(n) => Ok((r, EmptyListLit(n.clone()))), + NEListLit(xs) => { + Ok((r, NEListLit(xs.iter().rev().cloned().collect()))) } - ), - ListIndexed => improved_slice_patterns::match_vec!(args; - [_, EmptyListLit(t)] => { + _ => Err(()), + }, + (ListIndexed, [_, l, r..]) => match &*l.as_value() { + EmptyListLit(t) => { let mut kts = BTreeMap::new(); kts.insert( "index".into(), - TypeThunk::from_whnf( - Value::from_builtin(Natural) - ), + TypeThunk::from_whnf(Value::from_builtin(Natural)), ); - kts.insert("value".into(), t); - EmptyListLit(TypeThunk::from_whnf(RecordType(kts))) - }, - [_, NEListLit(xs)] => { + kts.insert("value".into(), t.clone()); + Ok((r, EmptyListLit(TypeThunk::from_whnf(RecordType(kts))))) + } + NEListLit(xs) => { let xs = xs - .into_iter() + .iter() .enumerate() .map(|(i, e)| { let i = NaturalLit(i); let mut kvs = BTreeMap::new(); kvs.insert("index".into(), Thunk::from_whnf(i)); - kvs.insert("value".into(), e); + kvs.insert("value".into(), e.clone()); Thunk::from_whnf(RecordLit(kvs)) }) .collect(); - NEListLit(xs) + Ok((r, NEListLit(xs))) } - ), - ListBuild => improved_slice_patterns::match_vec!(args; + _ => Err(()), + }, + (ListBuild, [t, f, r..]) => match &*f.as_value() { // fold/build fusion - [_, Value::AppliedBuiltin(ListFold, args)] => { - let mut args = args; + Value::AppliedBuiltin(ListFold, args) => { if args.len() >= 2 { - args.remove(1) + Ok((r, args[1].to_value())) } else { // Do we really need to handle this case ? unimplemented!() } - }, - [t, g] => g - .app(Value::from_builtin(List).app(t.clone())) - .app(ListConsClosure(TypeThunk::from_whnf(t.clone()), None)) - .app(EmptyListLit(TypeThunk::from_whnf(t))), - ), - ListFold => improved_slice_patterns::match_vec!(args; - // fold/build fusion - [_, Value::AppliedBuiltin(ListBuild, args)] => { - let mut args = args; - if args.len() >= 2 { - args.remove(1) - } else { - unimplemented!() - } - }, - [_, EmptyListLit(_), _, _, nil] => nil, - [_, NEListLit(xs), _, cons, nil] => { - let mut v = nil; - for x in xs.into_iter().rev() { - v = cons.clone().app_thunk(x).app(v); - } - v } - ), - OptionalBuild => improved_slice_patterns::match_vec!(args; - // fold/build fusion - [_, Value::AppliedBuiltin(OptionalFold, args)] => { - let mut args = args; - if args.len() >= 2 { - args.remove(1) - } else { - unimplemented!() + _ => Ok(( + r, + f.app_val(Value::from_builtin(List).app_thunk(t.clone())) + .app_val(ListConsClosure( + TypeThunk::from_thunk(t.clone()), + None, + )) + .app_val(EmptyListLit(TypeThunk::from_thunk(t.clone()))), + )), + }, + (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_value() { + EmptyListLit(_) => Ok((r, nil.to_value())), + NEListLit(xs) => { + let mut v = nil.clone(); + for x in xs.iter().rev() { + v = cons + .clone() + .app_thunk(x.clone()) + .app_thunk(v) + .into_thunk(); } - }, - [t, g] => g - .app(Value::from_builtin(Optional).app(t.clone())) - .app(OptionalSomeClosure(TypeThunk::from_whnf(t.clone()))) - .app(EmptyOptionalLit(TypeThunk::from_whnf(t))), - ), - OptionalFold => improved_slice_patterns::match_vec!(args; + Ok((r, v.to_value())) + } + _ => Err(()), + }, + (OptionalBuild, [t, f, r..]) => match &*f.as_value() { // fold/build fusion - [_, Value::AppliedBuiltin(OptionalBuild, args)] => { - let mut args = args; + Value::AppliedBuiltin(OptionalFold, args) => { if args.len() >= 2 { - args.remove(1) + Ok((r, args[1].to_value())) } else { + // Do we really need to handle this case ? unimplemented!() } - }, - [_, EmptyOptionalLit(_), _, _, nothing] => { - nothing - }, - [_, NEOptionalLit(x), _, just, _] => { - just.app_thunk(x) } - ), - NaturalBuild => improved_slice_patterns::match_vec!(args; - // fold/build fusion - [Value::AppliedBuiltin(NaturalFold, args)] => { - let mut args = args; - if args.len() >= 1 { - args.remove(0) - } else { - unimplemented!() - } - }, - [g] => g - .app(Value::from_builtin(Natural)) - .app(NaturalSuccClosure) - .app(NaturalLit(0)), - ), - NaturalFold => improved_slice_patterns::match_vec!(args; + _ => Ok(( + r, + f.app_val(Value::from_builtin(Optional).app_thunk(t.clone())) + .app_val(OptionalSomeClosure(TypeThunk::from_thunk( + t.clone(), + ))) + .app_val(EmptyOptionalLit(TypeThunk::from_thunk( + t.clone(), + ))), + )), + }, + (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_value() { + EmptyOptionalLit(_) => Ok((r, nothing.to_value())), + NEOptionalLit(x) => Ok((r, just.app_thunk(x.clone()))), + _ => Err(()), + }, + (NaturalBuild, [f, r..]) => match &*f.as_value() { // fold/build fusion - [Value::AppliedBuiltin(NaturalBuild, args)] => { - let mut args = args; + Value::AppliedBuiltin(NaturalFold, args) => { if args.len() >= 1 { - args.remove(0) + Ok((r, args[0].to_value())) } else { + // Do we really need to handle this case ? unimplemented!() } - }, - [NaturalLit(0), _, _, zero] => zero, - [NaturalLit(n), t, succ, zero] => { + } + _ => Ok(( + r, + f.app_val(Value::from_builtin(Natural)) + .app_val(NaturalSuccClosure) + .app_val(NaturalLit(0)), + )), + }, + (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_value() { + NaturalLit(0) => Ok((r, zero.to_value())), + NaturalLit(n) => { let fold = Value::from_builtin(NaturalFold) .app(NaturalLit(n - 1)) - .app(t) - .app(succ.clone()) - .app(zero); - succ.app(fold) - }, - ), - _ => Err(args), + .app_thunk(t.clone()) + .app_thunk(succ.clone()) + .app_thunk(zero.clone()); + Ok((r, succ.app_val(fold))) + } + _ => Err(()), + }, + _ => Err(()), }; - match ret { - Ok(x) => x, - Err(args) => AppliedBuiltin(b, args), + Ok((unconsumed_args, mut v)) => { + let n_consumed_args = args.len() - unconsumed_args.len(); + for x in args.into_iter().skip(n_consumed_args) { + v = v.app_thunk(x); + } + v + } + Err(()) => AppliedBuiltin(b, args), } } @@ -337,7 +338,7 @@ impl NormalizationContext { pub(crate) enum Value { /// Closures Lam(Label, Thunk, Thunk), - AppliedBuiltin(Builtin, Vec), + AppliedBuiltin(Builtin, Vec), /// `λ(x: a) -> Some x` OptionalSomeClosure(TypeThunk), /// `λ(x : a) -> λ(xs : List a) -> [ x ] # xs` @@ -671,6 +672,11 @@ impl Value { /// Apply to a value pub(crate) fn app(self, val: Value) -> Value { + self.app_val(val) + } + + /// Apply to a value + pub(crate) fn app_val(self, val: Value) -> Value { self.app_thunk(val.into_thunk()) } @@ -692,7 +698,7 @@ impl Value { e.subst_shift(&V(x, 0), &val).normalize_whnf().clone() } Value::AppliedBuiltin(b, mut args) => { - args.push(th.normalize_whnf().clone()); + args.push(th.clone()); apply_builtin(b, args) } Value::OptionalSomeClosure(_) => Value::NEOptionalLit(th), @@ -1136,6 +1142,22 @@ mod thunk { self.normalize_nf().normalize_to_expr() } + pub(crate) fn as_value(&self) -> Ref { + self.normalize_whnf() + } + + pub(crate) fn to_value(&self) -> Value { + self.normalize_whnf().clone() + } + + pub(crate) fn app_val(&self, val: Value) -> Value { + self.to_value().app(val) + } + + pub(crate) fn app_thunk(&self, th: Thunk) -> Value { + self.to_value().app_thunk(th) + } + pub(crate) fn shift(&self, delta: isize, var: &V