diff options
Diffstat (limited to 'dhall_core')
| -rw-r--r-- | dhall_core/src/core.rs | 350 |
1 files changed, 100 insertions, 250 deletions
diff --git a/dhall_core/src/core.rs b/dhall_core/src/core.rs index 51356cf..a3236eb 100644 --- a/dhall_core/src/core.rs +++ b/dhall_core/src/core.rs @@ -215,9 +215,7 @@ impl<N, E> InterpolatedText<N, E> { } } - pub fn iter( - &self, - ) -> impl Iterator<Item = InterpolatedTextContents<N, E>> { + pub fn iter(&self) -> impl Iterator<Item = InterpolatedTextContents<N, E>> { use std::iter::once; once(InterpolatedTextContents::Text(self.head.as_ref())).chain( self.tail.iter().flat_map(|(e, s)| { @@ -228,8 +226,7 @@ impl<N, E> InterpolatedText<N, E> { } } -impl<'a, N: 'a, E: 'a> - FromIterator<InterpolatedTextContents<'a, N, E>> +impl<'a, N: 'a, E: 'a> FromIterator<InterpolatedTextContents<'a, N, E>> for InterpolatedText<N, E> { fn from_iter<T>(iter: T) -> Self @@ -259,9 +256,7 @@ impl<'a, N: 'a, E: 'a> impl<N, E> Add for &InterpolatedText<N, E> { type Output = InterpolatedText<N, E>; fn add(self, rhs: &InterpolatedText<N, E>) -> Self::Output { - self.iter() - .chain(rhs.iter()) - .collect() + self.iter().chain(rhs.iter()).collect() } } @@ -418,34 +413,16 @@ impl<S, A> Expr<S, A> { F3: FnOnce(&A) -> B, F4: Fn(&Label) -> Label, { - map_shallow( + map_subexpr( self, |x| rc(map_expr(x.as_ref())), map_note, map_embed, map_label, + |_, x| rc(map_expr(x.as_ref())), ) } - pub fn map_shallow_rc<T, B, F1, F2, F3, F4>( - &self, - map_expr: F1, - map_note: F2, - map_embed: F3, - map_label: F4, - ) -> Expr<T, B> - where - A: Clone, - T: Clone, - S: Clone, - F1: Fn(&SubExpr<S, A>) -> SubExpr<T, B>, - F2: FnOnce(&S) -> T, - F3: FnOnce(&A) -> B, - F4: Fn(&Label) -> Label, - { - map_shallow(self, map_expr, map_note, map_embed, map_label) - } - pub fn map_embed<B, F>(&self, map_embed: &F) -> Expr<S, B> where A: Clone, @@ -885,102 +862,92 @@ fn add_ui(u: usize, i: isize) -> usize { } /// Map over the immediate children of the passed Expr -pub fn map_shallow<S, T, A, B, F1, F2, F3, F4>( +pub fn map_subexpr<S, T, A, B, F1, F2, F3, F4, F5>( e: &Expr<S, A>, map: F1, map_note: F2, map_embed: F3, map_label: F4, + map_under_binder: F5, ) -> Expr<T, B> where - A: Clone, - S: Clone, - T: Clone, F1: Fn(&SubExpr<S, A>) -> SubExpr<T, B>, F2: FnOnce(&S) -> T, F3: FnOnce(&A) -> B, F4: Fn(&Label) -> Label, + F5: FnOnce(&Label, &SubExpr<S, A>) -> SubExpr<T, B>, { use crate::Expr::*; let map = ↦ let opt = |x: &Option<_>| x.as_ref().map(&map); - match *e { - Const(k) => Const(k), - Var(V(ref x, n)) => Var(V(map_label(x), n)), - Lam(ref x, ref t, ref b) => Lam(map_label(x), map(t), map(b)), - Pi(ref x, ref t, ref b) => Pi(map_label(x), map(t), map(b)), - App(ref f, ref args) => { - let args = args.iter().map(map).collect(); - App(map(f), args) - } - Let(ref l, ref t, ref a, ref b) => { - Let(map_label(l), opt(t), map(a), map(b)) - } - Annot(ref x, ref t) => Annot(map(x), map(t)), - Builtin(v) => Builtin(v), - BoolLit(b) => BoolLit(b), - BoolIf(ref b, ref t, ref f) => BoolIf(map(b), map(t), map(f)), - NaturalLit(n) => NaturalLit(n), - IntegerLit(n) => IntegerLit(n), - DoubleLit(n) => DoubleLit(n), - TextLit(ref t) => TextLit(t.map(&map)), - BinOp(o, ref x, ref y) => BinOp(o, map(x), map(y)), - ListLit(ref t, ref es) => { - let es = es.iter().map(&map).collect(); - ListLit(opt(t), es) - } - OptionalLit(ref t, ref es) => OptionalLit(opt(t), opt(es)), - Record(ref kts) => { - Record(map_record_value_and_keys(kts, map, map_label)) - } - RecordLit(ref kvs) => { - RecordLit(map_record_value_and_keys(kvs, map, map_label)) + let vec = |x: &Vec<_>| x.iter().map(&map).collect(); + let btmap = |x: &BTreeMap<_, _>| { + x.into_iter().map(|(k, v)| (map_label(k), map(v))).collect() + }; + match e { + Const(k) => Const(*k), + Var(V(x, n)) => Var(V(map_label(x), *n)), + Lam(x, t, b) => Lam(map_label(x), map(t), map_under_binder(x, b)), + Pi(x, t, b) => Pi(map_label(x), map(t), map_under_binder(x, b)), + App(f, args) => App(map(f), vec(args)), + Let(l, t, a, b) => { + Let(map_label(l), opt(t), map(a), map_under_binder(l, b)) } - Union(ref kts) => Union(map_record_value_and_keys(kts, map, map_label)), - UnionLit(ref k, ref v, ref kvs) => UnionLit( - map_label(k), - map(v), - map_record_value_and_keys(kvs, map, map_label), - ), - Merge(ref x, ref y, ref t) => Merge(map(x), map(y), opt(t)), - Field(ref r, ref x) => Field(map(r), map_label(x)), - Note(ref n, ref e) => Note(map_note(n), map(e)), - Embed(ref a) => Embed(map_embed(a)), + Annot(x, t) => Annot(map(x), map(t)), + Builtin(v) => Builtin(*v), + BoolLit(b) => BoolLit(*b), + BoolIf(b, t, f) => BoolIf(map(b), map(t), map(f)), + NaturalLit(n) => NaturalLit(*n), + IntegerLit(n) => IntegerLit(*n), + DoubleLit(n) => DoubleLit(*n), + TextLit(t) => TextLit(t.map(&map)), + BinOp(o, x, y) => BinOp(*o, map(x), map(y)), + ListLit(t, es) => ListLit(opt(t), vec(es)), + OptionalLit(t, es) => OptionalLit(opt(t), opt(es)), + Record(kts) => Record(btmap(kts)), + RecordLit(kvs) => RecordLit(btmap(kvs)), + Union(kts) => Union(btmap(kts)), + UnionLit(k, v, kvs) => UnionLit(map_label(k), map(v), btmap(kvs)), + Merge(x, y, t) => Merge(map(x), map(y), opt(t)), + Field(r, x) => Field(map(r), map_label(x)), + Note(n, e) => Note(map_note(n), map(e)), + Embed(a) => Embed(map_embed(a)), } } -pub fn map_record_value<'a, I, K, V, U, F>(it: I, f: F) -> BTreeMap<K, U> -where - I: IntoIterator<Item = (&'a K, &'a V)>, - K: Eq + Ord + Clone + 'a, - V: 'a, - F: FnMut(&V) -> U, -{ - map_record_value_and_keys(it, f, |x| x.clone()) -} - -pub fn map_record_value_and_keys<'a, I, K, L, V, U, F, G>( - it: I, - mut f: F, - mut g: G, -) -> BTreeMap<L, U> +pub fn map_subexpr_rc_binder<S, A, F1, F2>( + e: &SubExpr<S, A>, + map_expr: F1, + map_under_binder: F2, +) -> SubExpr<S, A> where - I: IntoIterator<Item = (&'a K, &'a V)>, - K: Eq + Ord + 'a, - L: Eq + Ord + 'a, - V: 'a, - F: FnMut(&V) -> U, - G: FnMut(&K) -> L, + F1: Fn(&SubExpr<S, A>) -> SubExpr<S, A>, + F2: FnOnce(&Label, &SubExpr<S, A>) -> SubExpr<S, A>, { - it.into_iter().map(|(k, v)| (g(k), f(v))).collect() + match e.as_ref() { + Expr::Embed(_) => Rc::clone(e), + Expr::Note(_, e) => { + map_subexpr_rc_binder(e, map_expr, map_under_binder) + } + _ => rc(map_subexpr( + e, + map_expr, + |_| unreachable!(), + |_| unreachable!(), + Label::clone, + map_under_binder, + )), + } } -fn map_op2<T, U, V, F, G>(f: F, g: G, a: T, b: T) -> V +pub fn map_subexpr_rc<S, A, F1>( + e: &SubExpr<S, A>, + map_expr: F1, +) -> SubExpr<S, A> where - F: FnOnce(U, U) -> V, - G: Fn(T) -> U, + F1: Fn(&SubExpr<S, A>) -> SubExpr<S, A>, { - f(g(a), g(b)) + map_subexpr_rc_binder(e, &map_expr, |_, e| map_expr(e)) } /// `shift` is used by both normalization and type-checking to avoid variable @@ -1055,88 +1022,27 @@ where /// name in order to avoid shifting the bound variables by mistake. /// pub fn shift<S, A>( - d: isize, - v: &V, - e: &Rc<Expr<S, A>>, + delta: isize, + var: &V, + in_expr: &Rc<Expr<S, A>>, ) -> Rc<Expr<S, A>> { use crate::Expr::*; - let V(x, n) = v; - rc(match e.as_ref() { - Const(a) => Const(*a), - Var(V(x2, n2)) => { - let n3 = if x == x2 && n <= n2 { - add_ui(*n2, d) - } else { - *n2 - }; - Var(V(x2.clone(), n3)) - } - Lam(x2, tA, b) => { - let n2 = if x == x2 { n + 1 } else { *n }; - let tA2 = shift(d, v, tA); - let b2 = shift(d, &V(x.clone(), n2), b); - Lam(x2.clone(), tA2, b2) - } - Pi(x2, tA, tB) => { - let n2 = if x == x2 { n + 1 } else { *n }; - let tA2 = shift(d, v, tA); - let tB2 = shift(d, &V(x.clone(), n2), tB); - Pi(x2.clone(), tA2, tB2) - } - App(f, args) => { - let f = shift(d, v, f); - let args = args.iter().map(|a| shift(d, v, a)).collect(); - App(f, args) - } - Let(f, mt, r, e) => { - let n2 = if x == f { n + 1 } else { *n }; - let e2 = shift(d, &V(x.clone(), n2), e); - let mt2 = mt.as_ref().map(|t| shift(d, v, t)); - let r2 = shift(d, v, r); - Let(f.clone(), mt2, r2, e2) - } - Annot(a, b) => map_op2(Annot, |x| shift(d, v, x), a, b), - Builtin(v) => Builtin(*v), - BoolLit(a) => BoolLit(*a), - BinOp(o, a, b) => { - map_op2(|x, y| BinOp(*o, x, y), |x| shift(d, v, x), a, b) - } - BoolIf(a, b, c) => { - BoolIf(shift(d, v, a), shift(d, v, b), shift(d, v, c)) + let V(x, n) = var; + let under_binder = |y: &Label, e: &SubExpr<_, _>| { + let n = if x == y { n + 1 } else { *n }; + let newvar = &V(x.clone(), n); + shift(delta, newvar, e) + }; + match in_expr.as_ref() { + Var(V(y, m)) if x == y && n <= m => { + rc(Var(V(y.clone(), add_ui(*m, delta)))) } - NaturalLit(a) => NaturalLit(*a), - IntegerLit(a) => IntegerLit(*a), - DoubleLit(a) => DoubleLit(*a), - TextLit(a) => TextLit(a.map(|e| shift(d, v, &*e))), - ListLit(t, es) => ListLit( - t.as_ref().map(|t| shift(d, v, t)), - es.iter().map(|e| shift(d, v, e)).collect(), + _ => map_subexpr_rc_binder( + in_expr, + |e| shift(delta, var, e), + under_binder, ), - OptionalLit(t, e) => OptionalLit( - t.as_ref().map(|t| shift(d, v, t)), - e.as_ref().map(|t| shift(d, v, t)), - ), - Record(a) => Record(map_record_value(a, |val| shift(d, v, &*val))), - RecordLit(a) => { - RecordLit(map_record_value(a, |val| shift(d, v, &*val))) - } - Union(a) => Union(map_record_value(a, |val| shift(d, v, &*val))), - UnionLit(k, uv, a) => UnionLit( - k.clone(), - shift(d, v, uv), - map_record_value(a, |val| shift(d, v, &*val)), - ), - Merge(a, b, c) => Merge( - shift(d, v, a), - shift(d, v, b), - c.as_ref().map(|c| shift(d, v, c)), - ), - Field(a, b) => Field(shift(d, v, a), b.clone()), - Note(_, b) => return shift(d, v, b), - // The Dhall compiler enforces that all embedded values are closed expressions - // and `shift` does nothing to a closed expression - Embed(_) => return Rc::clone(e), - }) + } } /// Substitute all occurrences of a variable with an expression @@ -1146,79 +1052,23 @@ pub fn shift<S, A>( /// ``` /// pub fn subst<S, A>( - v: &V, - e: &Rc<Expr<S, A>>, - b: &Rc<Expr<S, A>>, -) -> Rc<Expr<S, A>> -{ + var: &V, + value: &Rc<Expr<S, A>>, + in_expr: &Rc<Expr<S, A>>, +) -> Rc<Expr<S, A>> { use crate::Expr::*; - let V(x, n) = v; - rc(match b.as_ref() { - Lam(y, tA, b) => { - let n2 = if x == y { n + 1 } else { *n }; - let b2 = - subst(&V(x.clone(), n2), &shift(1, &V(y.clone(), 0), e), b); - let tA2 = subst(v, e, tA); - Lam(y.clone(), tA2, b2) - } - Pi(y, tA, tB) => { - let n2 = if x == y { n + 1 } else { *n }; - let tB2 = - subst(&V(x.clone(), n2), &shift(1, &V(y.clone(), 0), e), tB); - let tA2 = subst(v, e, tA); - Pi(y.clone(), tA2, tB2) - } - App(f, args) => { - let f2 = subst(v, e, f); - let args = args.iter().map(|a| subst(v, e, a)).collect(); - App(f2, args) - } - Var(v2) if v == v2 => { - return e.clone(); - } - Let(f, mt, r, b) => { - let n2 = if x == f { n + 1 } else { *n }; - let b2 = - subst(&V(x.clone(), n2), &shift(1, &V(f.clone(), 0), e), b); - let mt2 = mt.as_ref().map(|t| subst(v, e, t)); - let r2 = subst(v, e, r); - Let(f.clone(), mt2, r2, b2) - } - Annot(a, b) => map_op2(Annot, |x| subst(v, e, x), a, b), - BinOp(o, a, b) => { - map_op2(|x, y| BinOp(*o, x, y), |x| subst(v, e, x), a, b) - } - BoolIf(a, b, c) => { - BoolIf(subst(v, e, a), subst(v, e, b), subst(v, e, c)) - } - TextLit(a) => TextLit(a.map(|b| subst(v, e, &*b))), - ListLit(a, b) => { - let a2 = a.as_ref().map(|a| subst(v, e, a)); - let b2 = b.iter().map(|be| subst(v, e, be)).collect(); - ListLit(a2, b2) - } - OptionalLit(a, b) => { - let a2 = a.as_ref().map(|a| subst(v, e, a)); - let b2 = b.as_ref().map(|a| subst(v, e, a)); - OptionalLit(a2, b2) - } - Record(kts) => Record(map_record_value(kts, |t| subst(v, e, &*t))), - RecordLit(kvs) => { - RecordLit(map_record_value(kvs, |val| subst(v, e, &*val))) - } - Union(kts) => Union(map_record_value(kts, |t| subst(v, e, &*t))), - UnionLit(k, uv, kvs) => UnionLit( - k.clone(), - subst(v, e, uv), - map_record_value(kvs, |val| subst(v, e, &*val)), - ), - Merge(a, b, c) => Merge( - subst(v, e, a), - subst(v, e, b), - c.as_ref().map(|c| subst(v, e, c)), + let under_binder = |y: &Label, e: &SubExpr<_, _>| { + let V(x, n) = var; + let n = if x == y { n + 1 } else { *n }; + let newvar = &V(x.clone(), n); + subst(newvar, &shift(1, &V(y.clone(), 0), value), e) + }; + match in_expr.as_ref() { + Var(v) if var == v => Rc::clone(value), + _ => map_subexpr_rc_binder( + in_expr, + |e| subst(var, value, e), + under_binder, ), - Field(a, b) => Field(subst(v, e, a), b.clone()), - Note(_, b) => return subst(v, e, b), - _ => return Rc::clone(b), - }) + } } |