diff options
Diffstat (limited to 'dhall/src/phase/normalize.rs')
| -rw-r--r-- | dhall/src/phase/normalize.rs | 953 |
1 files changed, 465 insertions, 488 deletions
diff --git a/dhall/src/phase/normalize.rs b/dhall/src/phase/normalize.rs index 405677a..3f6e99c 100644 --- a/dhall/src/phase/normalize.rs +++ b/dhall/src/phase/normalize.rs @@ -1,348 +1,431 @@ use std::collections::HashMap; +use dhall_syntax::Const::Type; use dhall_syntax::{ - BinOp, Builtin, ExprF, InterpolatedText, InterpolatedTextContents, - NaiveDouble, X, + BinOp, Builtin, ExprF, InterpolatedText, InterpolatedTextContents, Label, + NaiveDouble, }; -use crate::core::context::NormalizationContext; -use crate::core::thunk::{Thunk, TypeThunk}; use crate::core::value::Value; -use crate::core::var::Subst; -use crate::phase::{NormalizedSubExpr, ResolvedSubExpr, Typed}; - -pub type InputSubExpr = ResolvedSubExpr; -pub type OutputSubExpr = NormalizedSubExpr; +use crate::core::valuef::ValueF; +use crate::core::var::{AlphaLabel, Shift, Subst}; +use crate::phase::Normalized; + +// Ad-hoc macro to help construct closures +macro_rules! make_closure { + (#$var:ident) => { $var.clone() }; + (var($var:ident, $n:expr, $($ty:tt)*)) => {{ + let var = crate::core::var::AlphaVar::from_var_and_alpha( + Label::from(stringify!($var)).into(), + $n + ); + ValueF::Var(var) + .into_value_with_type(make_closure!($($ty)*)) + }}; + // Warning: assumes that $ty, as a dhall value, has type `Type` + (λ($var:ident : $($ty:tt)*) -> $($body:tt)*) => {{ + let var: AlphaLabel = Label::from(stringify!($var)).into(); + let ty = make_closure!($($ty)*); + let body = make_closure!($($body)*); + let body_ty = body.get_type_not_sort(); + let lam_ty = ValueF::Pi(var.clone(), ty.clone(), body_ty) + .into_value_with_type(Value::from_const(Type)); + ValueF::Lam(var, ty, body).into_value_with_type(lam_ty) + }}; + (Natural) => { + Value::from_builtin(Builtin::Natural) + }; + (List $($rest:tt)*) => { + Value::from_builtin(Builtin::List) + .app(make_closure!($($rest)*)) + }; + (Some($($rest:tt)*)) => {{ + let v = make_closure!($($rest)*); + let v_type = v.get_type_not_sort(); + let opt_v_type = Value::from_builtin(Builtin::Optional).app(v_type); + ValueF::NEOptionalLit(v).into_value_with_type(opt_v_type) + }}; + (1 + $($rest:tt)*) => { + ValueF::PartialExpr(ExprF::BinOp( + dhall_syntax::BinOp::NaturalPlus, + make_closure!($($rest)*), + Value::from_valuef_and_type( + ValueF::NaturalLit(1), + make_closure!(Natural) + ), + )).into_value_with_type( + make_closure!(Natural) + ) + }; + ([ $($head:tt)* ] # $($tail:tt)*) => {{ + let head = make_closure!($($head)*); + let tail = make_closure!($($tail)*); + let list_type = tail.get_type_not_sort(); + ValueF::PartialExpr(ExprF::BinOp( + dhall_syntax::BinOp::ListAppend, + ValueF::NEListLit(vec![head]) + .into_value_with_type(list_type.clone()), + tail, + )).into_value_with_type(list_type) + }}; +} #[allow(clippy::cognitive_complexity)] -pub fn apply_builtin(b: Builtin, args: Vec<Thunk>) -> Value { +pub(crate) fn apply_builtin( + b: Builtin, + args: Vec<Value>, + ty: &Value, +) -> ValueF { use dhall_syntax::Builtin::*; - use Value::*; + use ValueF::*; + + // Small helper enum + enum Ret<'a> { + ValueF(ValueF), + Value(Value), + // For applications that can return a function, it's important to keep the remaining + // arguments to apply them to the resulting function. + ValueWithRemainingArgs(&'a [Value], Value), + DoneAsIs, + } - // 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(()), + (OptionalNone, [t]) => Ret::ValueF(EmptyOptionalLit(t.clone())), + (NaturalIsZero, [n]) => match &*n.as_whnf() { + NaturalLit(n) => Ret::ValueF(BoolLit(*n == 0)), + _ => Ret::DoneAsIs, }, - (NaturalEven, [n, r..]) => match &*n.as_value() { - NaturalLit(n) => Ok((r, BoolLit(*n % 2 == 0))), - _ => Err(()), + (NaturalEven, [n]) => match &*n.as_whnf() { + NaturalLit(n) => Ret::ValueF(BoolLit(*n % 2 == 0)), + _ => Ret::DoneAsIs, }, - (NaturalOdd, [n, r..]) => match &*n.as_value() { - NaturalLit(n) => Ok((r, BoolLit(*n % 2 != 0))), - _ => Err(()), + (NaturalOdd, [n]) => match &*n.as_whnf() { + NaturalLit(n) => Ret::ValueF(BoolLit(*n % 2 != 0)), + _ => Ret::DoneAsIs, }, - (NaturalToInteger, [n, r..]) => match &*n.as_value() { - NaturalLit(n) => Ok((r, IntegerLit(*n as isize))), - _ => Err(()), + (NaturalToInteger, [n]) => match &*n.as_whnf() { + NaturalLit(n) => Ret::ValueF(IntegerLit(*n as isize)), + _ => Ret::DoneAsIs, }, - (NaturalShow, [n, r..]) => match &*n.as_value() { - NaturalLit(n) => Ok(( - r, - TextLit(vec![InterpolatedTextContents::Text(n.to_string())]), - )), - _ => Err(()), + (NaturalShow, [n]) => match &*n.as_whnf() { + NaturalLit(n) => { + Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text( + n.to_string(), + )])) + } + _ => Ret::DoneAsIs, }, - (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))), - _ if a == b => Ok((r, NaturalLit(0))), - _ => Err(()), + (NaturalSubtract, [a, b]) => match (&*a.as_whnf(), &*b.as_whnf()) { + (NaturalLit(a), NaturalLit(b)) => { + Ret::ValueF(NaturalLit(if b > a { b - a } else { 0 })) } - } - (IntegerShow, [n, r..]) => match &*n.as_value() { + (NaturalLit(0), _) => Ret::Value(b.clone()), + (_, NaturalLit(0)) => Ret::ValueF(NaturalLit(0)), + _ if a == b => Ret::ValueF(NaturalLit(0)), + _ => Ret::DoneAsIs, + }, + (IntegerShow, [n]) => match &*n.as_whnf() { IntegerLit(n) => { let s = if *n < 0 { n.to_string() } else { format!("+{}", n) }; - Ok((r, TextLit(vec![InterpolatedTextContents::Text(s)]))) + Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text(s)])) } - _ => Err(()), + _ => Ret::DoneAsIs, }, - (IntegerToDouble, [n, r..]) => match &*n.as_value() { - IntegerLit(n) => Ok((r, DoubleLit(NaiveDouble::from(*n as f64)))), - _ => Err(()), + (IntegerToDouble, [n]) => match &*n.as_whnf() { + IntegerLit(n) => { + Ret::ValueF(DoubleLit(NaiveDouble::from(*n as f64))) + } + _ => Ret::DoneAsIs, }, - (DoubleShow, [n, r..]) => match &*n.as_value() { - DoubleLit(n) => Ok(( - r, - TextLit(vec![InterpolatedTextContents::Text(n.to_string())]), - )), - _ => Err(()), + (DoubleShow, [n]) => match &*n.as_whnf() { + DoubleLit(n) => { + Ret::ValueF(TextLit(vec![InterpolatedTextContents::Text( + n.to_string(), + )])) + } + _ => Ret::DoneAsIs, }, - (TextShow, [v, r..]) => match &*v.as_value() { + (TextShow, [v]) => match &*v.as_whnf() { TextLit(elts) => { match elts.as_slice() { // Empty string literal. [] => { // Printing InterpolatedText takes care of all the escaping - let txt: InterpolatedText<X> = + let txt: InterpolatedText<Normalized> = std::iter::empty().collect(); let s = txt.to_string(); - Ok(( - r, - TextLit(vec![InterpolatedTextContents::Text(s)]), - )) + Ret::ValueF(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)] => { // Printing InterpolatedText takes care of all the escaping - let txt: InterpolatedText<X> = std::iter::once( - InterpolatedTextContents::Text(s.clone()), - ) - .collect(); + let txt: InterpolatedText<Normalized> = + std::iter::once(InterpolatedTextContents::Text( + s.clone(), + )) + .collect(); let s = txt.to_string(); - Ok(( - r, - TextLit(vec![InterpolatedTextContents::Text(s)]), - )) + Ret::ValueF(TextLit(vec![ + InterpolatedTextContents::Text(s), + ])) } - _ => Err(()), + _ => Ret::DoneAsIs, } } - _ => Err(()), + _ => Ret::DoneAsIs, }, - (ListLength, [_, l, r..]) => match &*l.as_value() { - EmptyListLit(_) => Ok((r, NaturalLit(0))), - NEListLit(xs) => Ok((r, NaturalLit(xs.len()))), - _ => Err(()), + (ListLength, [_, l]) => match &*l.as_whnf() { + EmptyListLit(_) => Ret::ValueF(NaturalLit(0)), + NEListLit(xs) => Ret::ValueF(NaturalLit(xs.len())), + _ => Ret::DoneAsIs, }, - (ListHead, [_, l, r..]) => match &*l.as_value() { - EmptyListLit(n) => Ok((r, EmptyOptionalLit(n.clone()))), + (ListHead, [_, l]) => match &*l.as_whnf() { + EmptyListLit(n) => Ret::ValueF(EmptyOptionalLit(n.clone())), NEListLit(xs) => { - Ok((r, NEOptionalLit(xs.iter().next().unwrap().clone()))) + Ret::ValueF(NEOptionalLit(xs.iter().next().unwrap().clone())) } - _ => Err(()), + _ => Ret::DoneAsIs, }, - (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()))) - } - _ => Err(()), + (ListLast, [_, l]) => match &*l.as_whnf() { + EmptyListLit(n) => Ret::ValueF(EmptyOptionalLit(n.clone())), + NEListLit(xs) => Ret::ValueF(NEOptionalLit( + xs.iter().rev().next().unwrap().clone(), + )), + _ => Ret::DoneAsIs, }, - (ListReverse, [_, l, r..]) => match &*l.as_value() { - EmptyListLit(n) => Ok((r, EmptyListLit(n.clone()))), + (ListReverse, [_, l]) => match &*l.as_whnf() { + EmptyListLit(n) => Ret::ValueF(EmptyListLit(n.clone())), NEListLit(xs) => { - Ok((r, NEListLit(xs.iter().rev().cloned().collect()))) + Ret::ValueF(NEListLit(xs.iter().rev().cloned().collect())) } - _ => Err(()), + _ => Ret::DoneAsIs, }, - (ListIndexed, [_, l, r..]) => match &*l.as_value() { - EmptyListLit(t) => { - let mut kts = HashMap::new(); - kts.insert( - "index".into(), - TypeThunk::from_value(Value::from_builtin(Natural)), - ); - kts.insert("value".into(), t.clone()); - Ok((r, EmptyListLit(TypeThunk::from_value(RecordType(kts))))) - } - NEListLit(xs) => { - let xs = xs - .iter() - .enumerate() - .map(|(i, e)| { - let i = NaturalLit(i); - let mut kvs = HashMap::new(); - kvs.insert("index".into(), Thunk::from_value(i)); - kvs.insert("value".into(), e.clone()); - Thunk::from_value(RecordLit(kvs)) - }) - .collect(); - Ok((r, NEListLit(xs))) + (ListIndexed, [_, l]) => { + let l_whnf = l.as_whnf(); + match &*l_whnf { + EmptyListLit(_) | NEListLit(_) => { + // Extract the type of the list elements + let t = match &*l_whnf { + EmptyListLit(t) => t.clone(), + NEListLit(xs) => xs[0].get_type_not_sort(), + _ => unreachable!(), + }; + + // Construct the returned record type: { index: Natural, value: t } + let mut kts = HashMap::new(); + kts.insert("index".into(), Value::from_builtin(Natural)); + kts.insert("value".into(), t.clone()); + let t = Value::from_valuef_and_type( + RecordType(kts), + Value::from_const(Type), + ); + + // Construct the new list, with added indices + let list = match &*l_whnf { + EmptyListLit(_) => EmptyListLit(t), + NEListLit(xs) => NEListLit( + xs.iter() + .enumerate() + .map(|(i, e)| { + let mut kvs = HashMap::new(); + kvs.insert( + "index".into(), + Value::from_valuef_and_type( + NaturalLit(i), + Value::from_builtin( + Builtin::Natural, + ), + ), + ); + kvs.insert("value".into(), e.clone()); + Value::from_valuef_and_type( + RecordLit(kvs), + t.clone(), + ) + }) + .collect(), + ), + _ => unreachable!(), + }; + Ret::ValueF(list) + } + _ => Ret::DoneAsIs, } - _ => Err(()), - }, - (ListBuild, [t, f, r..]) => match &*f.as_value() { + } + (ListBuild, [t, f]) => match &*f.as_whnf() { // fold/build fusion - Value::AppliedBuiltin(ListFold, args) => { + ValueF::AppliedBuiltin(ListFold, args) => { if args.len() >= 2 { - Ok((r, args[1].to_value())) + Ret::Value(args[1].clone()) } else { // Do we really need to handle this case ? 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()))), - )), + _ => { + let list_t = Value::from_builtin(List).app(t.clone()); + Ret::Value( + f.app(list_t.clone()) + .app({ + // Move `t` under new variables + let t1 = t.under_binder(Label::from("x")); + let t2 = t1.under_binder(Label::from("xs")); + make_closure!( + λ(x : #t) -> + λ(xs : List #t1) -> + [ var(x, 1, #t2) ] # var(xs, 0, List #t2) + ) + }) + .app( + EmptyListLit(t.clone()) + .into_value_with_type(list_t), + ), + ) + } }, - (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_value() { - EmptyListLit(_) => Ok((r, nil.to_value())), + (ListFold, [_, l, _, cons, nil, r..]) => match &*l.as_whnf() { + EmptyListLit(_) => Ret::ValueWithRemainingArgs(r, nil.clone()), 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(); + for x in xs.iter().cloned().rev() { + v = cons.app(x).app(v); } - Ok((r, v.to_value())) + Ret::ValueWithRemainingArgs(r, v) } - _ => Err(()), + _ => Ret::DoneAsIs, }, - (OptionalBuild, [t, f, r..]) => match &*f.as_value() { + (OptionalBuild, [t, f]) => match &*f.as_whnf() { // fold/build fusion - Value::AppliedBuiltin(OptionalFold, args) => { + ValueF::AppliedBuiltin(OptionalFold, args) => { if args.len() >= 2 { - Ok((r, args[1].to_value())) + Ret::Value(args[1].clone()) } else { // Do we really need to handle this case ? unimplemented!() } } - _ => 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(), - ))), - )), + _ => { + let optional_t = Value::from_builtin(Optional).app(t.clone()); + Ret::Value( + f.app(optional_t.clone()) + .app({ + let t1 = t.under_binder(Label::from("x")); + make_closure!(λ(x: #t) -> Some(var(x, 0, #t1))) + }) + .app( + EmptyOptionalLit(t.clone()) + .into_value_with_type(optional_t), + ), + ) + } }, - (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(()), + (OptionalFold, [_, v, _, just, nothing, r..]) => match &*v.as_whnf() { + EmptyOptionalLit(_) => { + Ret::ValueWithRemainingArgs(r, nothing.clone()) + } + NEOptionalLit(x) => { + Ret::ValueWithRemainingArgs(r, just.app(x.clone())) + } + _ => Ret::DoneAsIs, }, - (NaturalBuild, [f, r..]) => match &*f.as_value() { + (NaturalBuild, [f]) => match &*f.as_whnf() { // fold/build fusion - Value::AppliedBuiltin(NaturalFold, args) => { + ValueF::AppliedBuiltin(NaturalFold, args) => { if !args.is_empty() { - Ok((r, args[0].to_value())) + Ret::Value(args[0].clone()) } else { // Do we really need to handle this case ? unimplemented!() } } - _ => Ok(( - r, - f.app_val(Value::from_builtin(Natural)) - .app_val(NaturalSuccClosure) - .app_val(NaturalLit(0)), - )), + _ => Ret::Value( + f.app(Value::from_builtin(Natural)) + .app(make_closure!( + λ(x : Natural) -> 1 + var(x, 0, Natural) + )) + .app( + NaturalLit(0) + .into_value_with_type(Value::from_builtin(Natural)), + ), + ), }, - (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_value() { - NaturalLit(0) => Ok((r, zero.to_value())), + (NaturalFold, [n, t, succ, zero, r..]) => match &*n.as_whnf() { + NaturalLit(0) => Ret::ValueWithRemainingArgs(r, zero.clone()), NaturalLit(n) => { let fold = Value::from_builtin(NaturalFold) - .app(NaturalLit(n - 1)) - .app_thunk(t.clone()) - .app_thunk(succ.clone()) - .app_thunk(zero.clone()); - Ok((r, succ.app_val(fold))) + .app( + NaturalLit(n - 1) + .into_value_with_type(Value::from_builtin(Natural)), + ) + .app(t.clone()) + .app(succ.clone()) + .app(zero.clone()); + Ret::ValueWithRemainingArgs(r, succ.app(fold)) } - _ => Err(()), + _ => Ret::DoneAsIs, }, - _ => Err(()), + _ => Ret::DoneAsIs, }; match ret { - Ok((unconsumed_args, mut v)) => { + Ret::ValueF(v) => v, + Ret::Value(v) => v.to_whnf_check_type(ty), + Ret::ValueWithRemainingArgs(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 = v.app(x); } - v + v.to_whnf_check_type(ty) } - Err(()) => AppliedBuiltin(b, args), + Ret::DoneAsIs => AppliedBuiltin(b, args), } } -pub fn apply_any(f: Thunk, a: Thunk) -> Value { - let fallback = |f: Thunk, a: Thunk| Value::PartialExpr(ExprF::App(f, a)); - - let f_borrow = f.as_value(); +pub(crate) fn apply_any(f: Value, a: Value, ty: &Value) -> ValueF { + let f_borrow = f.as_whnf(); match &*f_borrow { - Value::Lam(x, _, e) => { - let val = Typed::from_thunk_untyped(a); - e.subst_shift(&x.into(), &val).to_value() + ValueF::Lam(x, _, e) => { + e.subst_shift(&x.into(), &a).to_whnf_check_type(ty) } - Value::AppliedBuiltin(b, args) => { + ValueF::AppliedBuiltin(b, args) => { use std::iter::once; let args = args.iter().cloned().chain(once(a.clone())).collect(); - apply_builtin(*b, args) - } - Value::OptionalSomeClosure(_) => Value::NEOptionalLit(a), - Value::ListConsClosure(t, None) => { - Value::ListConsClosure(t.clone(), Some(a)) + apply_builtin(*b, args, ty) } - Value::ListConsClosure(_, Some(x)) => { - let a_borrow = a.as_value(); - match &*a_borrow { - Value::EmptyListLit(_) => Value::NEListLit(vec![x.clone()]), - Value::NEListLit(xs) => { - use std::iter::once; - let xs = - once(x.clone()).chain(xs.iter().cloned()).collect(); - Value::NEListLit(xs) - } - _ => { - drop(f_borrow); - drop(a_borrow); - fallback(f, a) - } - } - } - Value::NaturalSuccClosure => { - let a_borrow = a.as_value(); - match &*a_borrow { - Value::NaturalLit(n) => Value::NaturalLit(n + 1), - _ => { - drop(f_borrow); - drop(a_borrow); - fallback(f, a) - } - } - } - Value::UnionConstructor(l, kts) => { - Value::UnionLit(l.clone(), a, kts.clone()) + ValueF::UnionConstructor(l, kts) => { + ValueF::UnionLit(l.clone(), a, kts.clone()) } _ => { drop(f_borrow); - fallback(f, a) + ValueF::PartialExpr(ExprF::App(f, a)) } } } -pub fn squash_textlit( - elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>, -) -> Vec<InterpolatedTextContents<Thunk>> { +pub(crate) fn squash_textlit( + elts: impl Iterator<Item = InterpolatedTextContents<Value>>, +) -> Vec<InterpolatedTextContents<Value>> { use std::mem::replace; use InterpolatedTextContents::{Expr, Text}; fn inner( - elts: impl Iterator<Item = InterpolatedTextContents<Thunk>>, + elts: impl Iterator<Item = InterpolatedTextContents<Value>>, crnt_str: &mut String, - ret: &mut Vec<InterpolatedTextContents<Thunk>>, + ret: &mut Vec<InterpolatedTextContents<Value>>, ) { for contents in elts { match contents { Text(s) => crnt_str.push_str(&s), Expr(e) => { - let e_borrow = e.as_value(); + let e_borrow = e.as_whnf(); match &*e_borrow { - Value::TextLit(elts2) => { + ValueF::TextLit(elts2) => { inner(elts2.iter().cloned(), crnt_str, ret) } _ => { @@ -367,134 +450,20 @@ pub fn squash_textlit( ret } -/// Reduces the imput expression to a Value. Evaluates as little as possible. -pub fn normalize_whnf(ctx: NormalizationContext, expr: InputSubExpr) -> Value { - match expr.as_ref() { - ExprF::Embed(e) => return e.to_value(), - ExprF::Var(v) => return ctx.lookup(v), - _ => {} - } - - // Thunk subexpressions - let expr: ExprF<Thunk, X> = - expr.as_ref().map_ref_with_special_handling_of_binders( - |e| Thunk::new(ctx.clone(), e.clone()), - |x, e| Thunk::new(ctx.skip(x), e.clone()), - |_| unreachable!(), - ); - - normalize_one_layer(expr) -} - -// Small helper enum to avoid repetition -enum Ret<'a> { - Value(Value), - Thunk(Thunk), - ThunkRef(&'a Thunk), - Expr(ExprF<Thunk, X>), -} - -/// Performs an intersection of two HashMaps. -/// -/// # Arguments -/// -/// * `f` - Will compute the final value from the intersecting -/// key and the values from both maps. -/// -/// # Description -/// -/// If the key is present in both maps then the final value for -/// that key is computed via the `f` function. -/// -/// The final map will contain the shared keys from the -/// two input maps with the final computed value from `f`. -pub(crate) fn intersection_with_key<K, T, U, V>( - mut f: impl FnMut(&K, &T, &U) -> V, - map1: &HashMap<K, T>, - map2: &HashMap<K, U>, -) -> HashMap<K, V> -where - K: std::hash::Hash + Eq + Clone, -{ - let mut kvs = HashMap::new(); - - for (k, t) in map1 { - // Only insert in the final map if the key exists in both - if let Some(u) = map2.get(k) { - kvs.insert(k.clone(), f(k, t, u)); - } - } - - kvs -} - -/// Performs an outer join of two HashMaps. -/// -/// # Arguments -/// -/// * `ft` - Will convert the values of the first map -/// into the target value. -/// -/// * `fu` - Will convert the values of the second map -/// into the target value. -/// -/// * `fktu` - Will convert the key and values from both maps -/// into the target type. -/// -/// # Description -/// -/// If the key is present in both maps then the final value for -/// that key is computed via the `fktu` function. Otherwise, the -/// final value will be calculated by either the `ft` or `fu` value -/// depending on which map the key is present in. -/// -/// The final map will contain all keys from the two input maps with -/// also values computed as per above. -pub(crate) fn outer_join<K, T, U, V>( - mut ft: impl FnMut(&T) -> V, - mut fu: impl FnMut(&U) -> V, - mut fktu: impl FnMut(&K, &T, &U) -> V, - map1: &HashMap<K, T>, - map2: &HashMap<K, U>, -) -> HashMap<K, V> -where - K: std::hash::Hash + Eq + Clone, -{ - let mut kvs = HashMap::new(); - - for (k1, t) in map1 { - let v = if let Some(u) = map2.get(k1) { - // The key exists in both maps - // so use all values for computation - fktu(k1, t, u) - } else { - // Key only exists in map1 - ft(t) - }; - kvs.insert(k1.clone(), v); - } - - for (k1, u) in map2 { - // Insert if key was missing in map1 - kvs.entry(k1.clone()).or_insert(fu(u)); - } - - kvs -} - -pub(crate) fn merge_maps<K, V>( +pub(crate) fn merge_maps<K, V, F, Err>( map1: &HashMap<K, V>, map2: &HashMap<K, V>, - mut f: impl FnMut(&V, &V) -> V, -) -> HashMap<K, V> + mut f: F, +) -> Result<HashMap<K, V>, Err> where + F: FnMut(&K, &V, &V) -> Result<V, Err>, K: std::hash::Hash + Eq + Clone, V: Clone, { let mut kvs = HashMap::new(); for (x, v2) in map2 { let newv = if let Some(v1) = map1.get(x) { - f(v1, v2) + f(x, v1, v2)? } else { v2.clone() }; @@ -504,85 +473,98 @@ where // Insert only if key not already present kvs.entry(x.clone()).or_insert_with(|| v1.clone()); } - kvs + Ok(kvs) } -fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> { +// Small helper enum to avoid repetition +enum Ret<'a> { + ValueF(ValueF), + Value(Value), + ValueRef(&'a Value), + Expr(ExprF<Value, Normalized>), +} + +fn apply_binop<'a>( + o: BinOp, + x: &'a Value, + y: &'a Value, + ty: &Value, +) -> Option<Ret<'a>> { use BinOp::{ BoolAnd, BoolEQ, BoolNE, BoolOr, Equivalence, ListAppend, NaturalPlus, NaturalTimes, RecursiveRecordMerge, RecursiveRecordTypeMerge, RightBiasedRecordMerge, TextAppend, }; - use Value::{ + use ValueF::{ BoolLit, EmptyListLit, NEListLit, NaturalLit, RecordLit, RecordType, TextLit, }; - let x_borrow = x.as_value(); - let y_borrow = y.as_value(); + let x_borrow = x.as_whnf(); + let y_borrow = y.as_whnf(); Some(match (o, &*x_borrow, &*y_borrow) { - (BoolAnd, BoolLit(true), _) => Ret::ThunkRef(y), - (BoolAnd, _, BoolLit(true)) => Ret::ThunkRef(x), - (BoolAnd, BoolLit(false), _) => Ret::Value(BoolLit(false)), - (BoolAnd, _, BoolLit(false)) => Ret::Value(BoolLit(false)), - (BoolAnd, _, _) if x == y => Ret::ThunkRef(x), - (BoolOr, BoolLit(true), _) => Ret::Value(BoolLit(true)), - (BoolOr, _, BoolLit(true)) => Ret::Value(BoolLit(true)), - (BoolOr, BoolLit(false), _) => Ret::ThunkRef(y), - (BoolOr, _, BoolLit(false)) => Ret::ThunkRef(x), - (BoolOr, _, _) if x == y => Ret::ThunkRef(x), - (BoolEQ, BoolLit(true), _) => Ret::ThunkRef(y), - (BoolEQ, _, BoolLit(true)) => Ret::ThunkRef(x), - (BoolEQ, BoolLit(x), BoolLit(y)) => Ret::Value(BoolLit(x == y)), - (BoolEQ, _, _) if x == y => Ret::Value(BoolLit(true)), - (BoolNE, BoolLit(false), _) => Ret::ThunkRef(y), - (BoolNE, _, BoolLit(false)) => Ret::ThunkRef(x), - (BoolNE, BoolLit(x), BoolLit(y)) => Ret::Value(BoolLit(x != y)), - (BoolNE, _, _) if x == y => Ret::Value(BoolLit(false)), - - (NaturalPlus, NaturalLit(0), _) => Ret::ThunkRef(y), - (NaturalPlus, _, NaturalLit(0)) => Ret::ThunkRef(x), + (BoolAnd, BoolLit(true), _) => Ret::ValueRef(y), + (BoolAnd, _, BoolLit(true)) => Ret::ValueRef(x), + (BoolAnd, BoolLit(false), _) => Ret::ValueF(BoolLit(false)), + (BoolAnd, _, BoolLit(false)) => Ret::ValueF(BoolLit(false)), + (BoolAnd, _, _) if x == y => Ret::ValueRef(x), + (BoolOr, BoolLit(true), _) => Ret::ValueF(BoolLit(true)), + (BoolOr, _, BoolLit(true)) => Ret::ValueF(BoolLit(true)), + (BoolOr, BoolLit(false), _) => Ret::ValueRef(y), + (BoolOr, _, BoolLit(false)) => Ret::ValueRef(x), + (BoolOr, _, _) if x == y => Ret::ValueRef(x), + (BoolEQ, BoolLit(true), _) => Ret::ValueRef(y), + (BoolEQ, _, BoolLit(true)) => Ret::ValueRef(x), + (BoolEQ, BoolLit(x), BoolLit(y)) => Ret::ValueF(BoolLit(x == y)), + (BoolEQ, _, _) if x == y => Ret::ValueF(BoolLit(true)), + (BoolNE, BoolLit(false), _) => Ret::ValueRef(y), + (BoolNE, _, BoolLit(false)) => Ret::ValueRef(x), + (BoolNE, BoolLit(x), BoolLit(y)) => Ret::ValueF(BoolLit(x != y)), + (BoolNE, _, _) if x == y => Ret::ValueF(BoolLit(false)), + + (NaturalPlus, NaturalLit(0), _) => Ret::ValueRef(y), + (NaturalPlus, _, NaturalLit(0)) => Ret::ValueRef(x), (NaturalPlus, NaturalLit(x), NaturalLit(y)) => { - Ret::Value(NaturalLit(x + y)) + Ret::ValueF(NaturalLit(x + y)) } - (NaturalTimes, NaturalLit(0), _) => Ret::Value(NaturalLit(0)), - (NaturalTimes, _, NaturalLit(0)) => Ret::Value(NaturalLit(0)), - (NaturalTimes, NaturalLit(1), _) => Ret::ThunkRef(y), - (NaturalTimes, _, NaturalLit(1)) => Ret::ThunkRef(x), + (NaturalTimes, NaturalLit(0), _) => Ret::ValueF(NaturalLit(0)), + (NaturalTimes, _, NaturalLit(0)) => Ret::ValueF(NaturalLit(0)), + (NaturalTimes, NaturalLit(1), _) => Ret::ValueRef(y), + (NaturalTimes, _, NaturalLit(1)) => Ret::ValueRef(x), (NaturalTimes, NaturalLit(x), NaturalLit(y)) => { - Ret::Value(NaturalLit(x * y)) + Ret::ValueF(NaturalLit(x * y)) } - (ListAppend, EmptyListLit(_), _) => Ret::ThunkRef(y), - (ListAppend, _, EmptyListLit(_)) => Ret::ThunkRef(x), - (ListAppend, NEListLit(xs), NEListLit(ys)) => { - Ret::Value(NEListLit(xs.iter().chain(ys.iter()).cloned().collect())) - } + (ListAppend, EmptyListLit(_), _) => Ret::ValueRef(y), + (ListAppend, _, EmptyListLit(_)) => Ret::ValueRef(x), + (ListAppend, NEListLit(xs), NEListLit(ys)) => Ret::ValueF(NEListLit( + xs.iter().chain(ys.iter()).cloned().collect(), + )), - (TextAppend, TextLit(x), _) if x.is_empty() => Ret::ThunkRef(y), - (TextAppend, _, TextLit(y)) if y.is_empty() => Ret::ThunkRef(x), - (TextAppend, TextLit(x), TextLit(y)) => Ret::Value(TextLit( + (TextAppend, TextLit(x), _) if x.is_empty() => Ret::ValueRef(y), + (TextAppend, _, TextLit(y)) if y.is_empty() => Ret::ValueRef(x), + (TextAppend, TextLit(x), TextLit(y)) => Ret::ValueF(TextLit( squash_textlit(x.iter().chain(y.iter()).cloned()), )), (TextAppend, TextLit(x), _) => { use std::iter::once; let y = InterpolatedTextContents::Expr(y.clone()); - Ret::Value(TextLit(squash_textlit( + Ret::ValueF(TextLit(squash_textlit( x.iter().cloned().chain(once(y)), ))) } (TextAppend, _, TextLit(y)) => { use std::iter::once; let x = InterpolatedTextContents::Expr(x.clone()); - Ret::Value(TextLit(squash_textlit( + Ret::ValueF(TextLit(squash_textlit( once(x).chain(y.iter().cloned()), ))) } (RightBiasedRecordMerge, _, RecordLit(kvs)) if kvs.is_empty() => { - Ret::ThunkRef(x) + Ret::ValueRef(x) } (RightBiasedRecordMerge, RecordLit(kvs), _) if kvs.is_empty() => { - Ret::ThunkRef(y) + Ret::ValueRef(y) } (RightBiasedRecordMerge, RecordLit(kvs1), RecordLit(kvs2)) => { let mut kvs = kvs2.clone(); @@ -590,92 +572,83 @@ fn apply_binop<'a>(o: BinOp, x: &'a Thunk, y: &'a Thunk) -> Option<Ret<'a>> { // Insert only if key not already present kvs.entry(x.clone()).or_insert_with(|| v.clone()); } - Ret::Value(RecordLit(kvs)) + Ret::ValueF(RecordLit(kvs)) } (RecursiveRecordMerge, _, RecordLit(kvs)) if kvs.is_empty() => { - Ret::ThunkRef(x) + Ret::ValueRef(x) } (RecursiveRecordMerge, RecordLit(kvs), _) if kvs.is_empty() => { - Ret::ThunkRef(y) + Ret::ValueRef(y) } (RecursiveRecordMerge, RecordLit(kvs1), RecordLit(kvs2)) => { - let kvs = merge_maps(kvs1, kvs2, |v1, v2| { - Thunk::from_partial_expr(ExprF::BinOp( - RecursiveRecordMerge, - v1.clone(), - v2.clone(), + let ty_borrow = ty.as_whnf(); + let kts = match &*ty_borrow { + RecordType(kts) => kts, + _ => unreachable!("Internal type error"), + }; + let kvs = merge_maps::<_, _, _, !>(kvs1, kvs2, |k, v1, v2| { + Ok(Value::from_valuef_and_type( + ValueF::PartialExpr(ExprF::BinOp( + RecursiveRecordMerge, + v1.clone(), + v2.clone(), + )), + kts.get(k).expect("Internal type error").clone(), )) - }); - Ret::Value(RecordLit(kvs)) + })?; + Ret::ValueF(RecordLit(kvs)) } - (RecursiveRecordTypeMerge, _, RecordType(kvs)) if kvs.is_empty() => { - Ret::ThunkRef(x) - } - (RecursiveRecordTypeMerge, RecordType(kvs), _) if kvs.is_empty() => { - Ret::ThunkRef(y) + (RecursiveRecordTypeMerge, _, _) | (Equivalence, _, _) => { + unreachable!("This case should have been handled in typecheck") } - (RecursiveRecordTypeMerge, RecordType(kvs1), RecordType(kvs2)) => { - let kvs = merge_maps(kvs1, kvs2, |v1, v2| { - TypeThunk::from_thunk(Thunk::from_partial_expr(ExprF::BinOp( - RecursiveRecordTypeMerge, - v1.to_thunk(), - v2.to_thunk(), - ))) - }); - Ret::Value(RecordType(kvs)) - } - - (Equivalence, _, _) => Ret::Value(Value::Equivalence( - TypeThunk::from_thunk(x.clone()), - TypeThunk::from_thunk(y.clone()), - )), _ => return None, }) } -pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { - use Value::{ - AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit, Lam, - NEListLit, NEOptionalLit, NaturalLit, Pi, RecordLit, RecordType, - TextLit, UnionConstructor, UnionLit, UnionType, +pub(crate) fn normalize_one_layer( + expr: ExprF<Value, Normalized>, + ty: &Value, +) -> ValueF { + use ValueF::{ + AppliedBuiltin, BoolLit, DoubleLit, EmptyListLit, IntegerLit, + NEListLit, NEOptionalLit, NaturalLit, RecordLit, TextLit, + UnionConstructor, UnionLit, UnionType, }; let ret = match expr { - ExprF::Embed(_) => unreachable!(), - ExprF::Var(_) => unreachable!(), - ExprF::Annot(x, _) => Ret::Thunk(x), - ExprF::Assert(_) => Ret::Expr(expr), - ExprF::Lam(x, t, e) => { - Ret::Value(Lam(x.into(), TypeThunk::from_thunk(t), e)) + ExprF::Import(_) => unreachable!( + "There should remain no imports in a resolved expression" + ), + // Those cases have already been completely handled in the typechecking phase (using + // `RetWhole`), so they won't appear here. + ExprF::Lam(_, _, _) + | ExprF::Pi(_, _, _) + | ExprF::Let(_, _, _, _) + | ExprF::Embed(_) + | ExprF::Const(_) + | ExprF::Builtin(_) + | ExprF::Var(_) + | ExprF::Annot(_, _) + | ExprF::RecordType(_) + | ExprF::UnionType(_) => { + unreachable!("This case should have been handled in typecheck") } - ExprF::Pi(x, t, e) => Ret::Value(Pi( - x.into(), - TypeThunk::from_thunk(t), - TypeThunk::from_thunk(e), - )), - ExprF::Let(x, _, v, b) => { - let v = Typed::from_thunk_untyped(v); - Ret::Thunk(b.subst_shift(&x.into(), &v)) - } - ExprF::App(v, a) => Ret::Value(v.app_thunk(a)), - ExprF::Builtin(b) => Ret::Value(Value::from_builtin(b)), - ExprF::Const(c) => Ret::Value(Value::Const(c)), - ExprF::BoolLit(b) => Ret::Value(BoolLit(b)), - ExprF::NaturalLit(n) => Ret::Value(NaturalLit(n)), - ExprF::IntegerLit(n) => Ret::Value(IntegerLit(n)), - ExprF::DoubleLit(n) => Ret::Value(DoubleLit(n)), - ExprF::SomeLit(e) => Ret::Value(NEOptionalLit(e)), + ExprF::Assert(_) => Ret::Expr(expr), + ExprF::App(v, a) => Ret::Value(v.app(a)), + ExprF::BoolLit(b) => Ret::ValueF(BoolLit(b)), + ExprF::NaturalLit(n) => Ret::ValueF(NaturalLit(n)), + ExprF::IntegerLit(n) => Ret::ValueF(IntegerLit(n)), + ExprF::DoubleLit(n) => Ret::ValueF(DoubleLit(n)), + ExprF::SomeLit(e) => Ret::ValueF(NEOptionalLit(e)), ExprF::EmptyListLit(ref t) => { // Check if the type is of the form `List x` - let t_borrow = t.as_value(); + let t_borrow = t.as_whnf(); match &*t_borrow { AppliedBuiltin(Builtin::List, args) if args.len() == 1 => { - Ret::Value(EmptyListLit(TypeThunk::from_thunk( - args[0].clone(), - ))) + Ret::ValueF(EmptyListLit(args[0].clone())) } _ => { drop(t_borrow); @@ -684,43 +657,33 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { } } ExprF::NEListLit(elts) => { - Ret::Value(NEListLit(elts.into_iter().collect())) + Ret::ValueF(NEListLit(elts.into_iter().collect())) } ExprF::RecordLit(kvs) => { - Ret::Value(RecordLit(kvs.into_iter().collect())) + Ret::ValueF(RecordLit(kvs.into_iter().collect())) } - ExprF::RecordType(kts) => Ret::Value(RecordType( - kts.into_iter() - .map(|(k, t)| (k, 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)))) - .collect(), - )), ExprF::TextLit(elts) => { use InterpolatedTextContents::Expr; let elts: Vec<_> = squash_textlit(elts.into_iter()); // Simplify bare interpolation if let [Expr(th)] = elts.as_slice() { - Ret::Thunk(th.clone()) + Ret::Value(th.clone()) } else { - Ret::Value(TextLit(elts)) + Ret::ValueF(TextLit(elts)) } } ExprF::BoolIf(ref b, ref e1, ref e2) => { - let b_borrow = b.as_value(); + let b_borrow = b.as_whnf(); match &*b_borrow { - BoolLit(true) => Ret::ThunkRef(e1), - BoolLit(false) => Ret::ThunkRef(e2), + BoolLit(true) => Ret::ValueRef(e1), + BoolLit(false) => Ret::ValueRef(e2), _ => { - let e1_borrow = e1.as_value(); - let e2_borrow = e2.as_value(); + let e1_borrow = e1.as_whnf(); + let e2_borrow = e2.as_whnf(); match (&*e1_borrow, &*e2_borrow) { // Simplify `if b then True else False` - (BoolLit(true), BoolLit(false)) => Ret::ThunkRef(b), - _ if e1 == e2 => Ret::ThunkRef(e1), + (BoolLit(true), BoolLit(false)) => Ret::ValueRef(b), + _ if e1 == e2 => Ret::ValueRef(e1), _ => { drop(b_borrow); drop(e1_borrow); @@ -731,18 +694,18 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { } } } - ExprF::BinOp(o, ref x, ref y) => match apply_binop(o, x, y) { + ExprF::BinOp(o, ref x, ref y) => match apply_binop(o, x, y, ty) { Some(ret) => ret, None => Ret::Expr(expr), }, - ExprF::Projection(_, ls) if ls.is_empty() => { - Ret::Value(RecordLit(HashMap::new())) + ExprF::Projection(_, ref ls) if ls.is_empty() => { + Ret::ValueF(RecordLit(HashMap::new())) } ExprF::Projection(ref v, ref ls) => { - let v_borrow = v.as_value(); + let v_borrow = v.as_whnf(); match &*v_borrow { - RecordLit(kvs) => Ret::Value(RecordLit( + RecordLit(kvs) => Ret::ValueF(RecordLit( ls.iter() .filter_map(|l| { kvs.get(l).map(|x| (l.clone(), x.clone())) @@ -756,17 +719,17 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { } } ExprF::Field(ref v, ref l) => { - let v_borrow = v.as_value(); + let v_borrow = v.as_whnf(); match &*v_borrow { RecordLit(kvs) => match kvs.get(l) { - Some(r) => Ret::Thunk(r.clone()), + Some(r) => Ret::Value(r.clone()), None => { drop(v_borrow); Ret::Expr(expr) } }, UnionType(kts) => { - Ret::Value(UnionConstructor(l.clone(), kts.clone())) + Ret::ValueF(UnionConstructor(l.clone(), kts.clone())) } _ => { drop(v_borrow); @@ -776,11 +739,11 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { } ExprF::Merge(ref handlers, ref variant, _) => { - let handlers_borrow = handlers.as_value(); - let variant_borrow = variant.as_value(); + let handlers_borrow = handlers.as_whnf(); + let variant_borrow = variant.as_whnf(); match (&*handlers_borrow, &*variant_borrow) { (RecordLit(kvs), UnionConstructor(l, _)) => match kvs.get(l) { - Some(h) => Ret::Thunk(h.clone()), + Some(h) => Ret::Value(h.clone()), None => { drop(handlers_borrow); drop(variant_borrow); @@ -788,7 +751,7 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { } }, (RecordLit(kvs), UnionLit(l, v, _)) => match kvs.get(l) { - Some(h) => Ret::Value(h.app_thunk(v.clone())), + Some(h) => Ret::Value(h.app(v.clone())), None => { drop(handlers_borrow); drop(variant_borrow); @@ -802,12 +765,26 @@ pub fn normalize_one_layer(expr: ExprF<Thunk, X>) -> Value { } } } + ExprF::ToMap(_, _) => unimplemented!("toMap"), }; match ret { - Ret::Value(v) => v, - Ret::Thunk(th) => th.to_value(), - Ret::ThunkRef(th) => th.to_value(), - Ret::Expr(expr) => Value::PartialExpr(expr), + Ret::ValueF(v) => v, + Ret::Value(v) => v.to_whnf_check_type(ty), + Ret::ValueRef(v) => v.to_whnf_check_type(ty), + Ret::Expr(expr) => ValueF::PartialExpr(expr), + } +} + +/// Normalize a ValueF into WHNF +pub(crate) fn normalize_whnf(v: ValueF, ty: &Value) -> ValueF { + match v { + ValueF::AppliedBuiltin(b, args) => apply_builtin(b, args, ty), + ValueF::PartialExpr(e) => normalize_one_layer(e, ty), + ValueF::TextLit(elts) => { + ValueF::TextLit(squash_textlit(elts.into_iter())) + } + // All other cases are already in WHNF + v => v, } } |