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authorNanoTech2016-12-08 21:24:26 +0000
committerNanoTech2017-03-10 23:48:28 -0600
commit1619be740b2a050fd172523226002e9ea141e38b (patch)
tree9596ac676310aaf6aed59c035ede2267a30a2fde
parent54064666084d6dfa3eaecb7ba51c09c28b8cf987 (diff)
subst: Don't need to match on the left Expr
-rw-r--r--src/core.rs24
1 files changed, 12 insertions, 12 deletions
diff --git a/src/core.rs b/src/core.rs
index 3171a8c..e9f185c 100644
--- a/src/core.rs
+++ b/src/core.rs
@@ -508,41 +508,41 @@ shift _ _ (Embed p) = Embed p
/// subst x C B ~ B[x := C]
/// ```
///
-pub fn subst<'i, S, T, A>(v: V<'i>, a: &Expr<'i, S, A>, b: &Expr<'i, T, A>) -> Expr<'i, S, A>
+pub fn subst<'i, S, T, A>(v: V<'i>, e: &Expr<'i, S, A>, b: &Expr<'i, T, A>) -> Expr<'i, S, A>
where S: Clone + ::std::fmt::Debug,
T: Clone + ::std::fmt::Debug,
- A: Clone + ::std::fmt::Debug,
+ A: Clone + ::std::fmt::Debug
{
use Expr::*;
let V(x, n) = v;
- match (a, b) {
- (_, &Const(a)) => Const(a),
- (e, &Lam(y, ref tA, ref b)) => {
+ match b {
+ &Const(a) => Const(a),
+ &Lam(y, ref tA, ref b) => {
let n2 = if x == y { n + 1 } else { n };
let b2 = subst(V(x, n2), &shift(1, V(y, 0), &e), b);
let tA2 = subst(V(x, n), &e, tA);
Lam(y, bx(tA2), bx(b2))
}
- (e, &Pi(y, ref tA, ref tB)) => {
+ &Pi(y, ref tA, ref tB) => {
let n2 = if x == y { n + 1 } else { n };
let tB2 = subst(V(x, n2), &shift(1, V(y, 0), &e), tB);
let tA2 = subst(V(x, n), &e, tA);
pi(y, tA2, tB2)
}
- (e, &App(ref f, ref a)) => {
+ &App(ref f, ref a) => {
let f2 = subst(v, e, f);
let a2 = subst(v, e, a);
app(f2, a2)
}
- (e, &Var(v2)) => if v == v2 { e.clone() } else { Var(v2) },
- (e, &ListLit(ref a, ref b)) => {
+ &Var(v2) => if v == v2 { e.clone() } else { Var(v2) },
+ &ListLit(ref a, ref b) => {
let a2 = subst(v, e, a);
let b2 = b.iter().map(|be| subst(v, e, be)).collect();
ListLit(bx(a2), b2)
}
- (_, &BuiltinType(t)) => BuiltinType(t),
- (_, &BuiltinValue(v)) => BuiltinValue(v),
- (a, b) => panic!("Unimplemented subst case: {:?}", (v, a, b)),
+ &BuiltinType(t) => BuiltinType(t),
+ &BuiltinValue(v) => BuiltinValue(v),
+ b => panic!("Unimplemented subst case: {:?}", (v, e, b)),
}
}