aboutsummaryrefslogtreecommitdiff
path: root/crates/libsyntax2/src/algo
diff options
context:
space:
mode:
Diffstat (limited to 'crates/libsyntax2/src/algo')
-rw-r--r--crates/libsyntax2/src/algo/visit.rs58
-rw-r--r--crates/libsyntax2/src/algo/walk.rs10
2 files changed, 63 insertions, 5 deletions
diff --git a/crates/libsyntax2/src/algo/visit.rs b/crates/libsyntax2/src/algo/visit.rs
index a36c8f45e..9f1c127c7 100644
--- a/crates/libsyntax2/src/algo/visit.rs
+++ b/crates/libsyntax2/src/algo/visit.rs
@@ -6,6 +6,10 @@ pub fn visitor<'a, T>() -> impl Visitor<'a, Output=T> {
6 EmptyVisitor { ph: PhantomData } 6 EmptyVisitor { ph: PhantomData }
7} 7}
8 8
9pub fn visitor_ctx<'a, T, C>(ctx: C) -> impl VisitorCtx<'a, Output=T, Ctx=C> {
10 EmptyVisitorCtx { ph: PhantomData, ctx }
11}
12
9pub trait Visitor<'a>: Sized { 13pub trait Visitor<'a>: Sized {
10 type Output; 14 type Output;
11 fn accept(self, node: SyntaxNodeRef<'a>) -> Option<Self::Output>; 15 fn accept(self, node: SyntaxNodeRef<'a>) -> Option<Self::Output>;
@@ -17,6 +21,18 @@ pub trait Visitor<'a>: Sized {
17 } 21 }
18} 22}
19 23
24pub trait VisitorCtx<'a>: Sized {
25 type Output;
26 type Ctx;
27 fn accept(self, node: SyntaxNodeRef<'a>) -> Result<Self::Output, Self::Ctx>;
28 fn visit<N, F>(self, f: F) -> VisCtx<Self, N, F>
29 where N: AstNode<'a>,
30 F: FnOnce(N, Self::Ctx) -> Self::Output,
31 {
32 VisCtx { inner: self, f, ph: PhantomData }
33 }
34}
35
20#[derive(Debug)] 36#[derive(Debug)]
21struct EmptyVisitor<T> { 37struct EmptyVisitor<T> {
22 ph: PhantomData<fn() -> T> 38 ph: PhantomData<fn() -> T>
@@ -31,6 +47,21 @@ impl<'a, T> Visitor<'a> for EmptyVisitor<T> {
31} 47}
32 48
33#[derive(Debug)] 49#[derive(Debug)]
50struct EmptyVisitorCtx<T, C> {
51 ctx: C,
52 ph: PhantomData<fn() -> T>,
53}
54
55impl<'a, T, C> VisitorCtx<'a> for EmptyVisitorCtx<T, C> {
56 type Output = T;
57 type Ctx = C;
58
59 fn accept(self, _node: SyntaxNodeRef<'a>) -> Result<T, C> {
60 Err(self.ctx)
61 }
62}
63
64#[derive(Debug)]
34pub struct Vis<V, N, F> { 65pub struct Vis<V, N, F> {
35 inner: V, 66 inner: V,
36 f: F, 67 f: F,
@@ -50,3 +81,30 @@ impl<'a, V, N, F> Visitor<'a> for Vis<V, N, F>
50 inner.accept(node).or_else(|| N::cast(node).map(f)) 81 inner.accept(node).or_else(|| N::cast(node).map(f))
51 } 82 }
52} 83}
84
85#[derive(Debug)]
86pub struct VisCtx<V, N, F> {
87 inner: V,
88 f: F,
89 ph: PhantomData<fn(N)>,
90}
91
92impl<'a, V, N, F> VisitorCtx<'a> for VisCtx<V, N, F>
93 where
94 V: VisitorCtx<'a>,
95 N: AstNode<'a>,
96 F: FnOnce(N, <V as VisitorCtx<'a>>::Ctx) -> <V as VisitorCtx<'a>>::Output,
97{
98 type Output = <V as VisitorCtx<'a>>::Output;
99 type Ctx = <V as VisitorCtx<'a>>::Ctx;
100
101 fn accept(self, node: SyntaxNodeRef<'a>) -> Result<Self::Output, Self::Ctx> {
102 let VisCtx { inner, f, .. } = self;
103 inner.accept(node).or_else(|ctx|
104 match N::cast(node) {
105 None => Err(ctx),
106 Some(node) => Ok(f(node, ctx))
107 }
108 )
109 }
110}
diff --git a/crates/libsyntax2/src/algo/walk.rs b/crates/libsyntax2/src/algo/walk.rs
index d8797c453..536ee705f 100644
--- a/crates/libsyntax2/src/algo/walk.rs
+++ b/crates/libsyntax2/src/algo/walk.rs
@@ -17,19 +17,19 @@ pub enum WalkEvent<'a> {
17} 17}
18 18
19pub fn walk<'a>(root: SyntaxNodeRef<'a>) -> impl Iterator<Item = WalkEvent<'a>> { 19pub fn walk<'a>(root: SyntaxNodeRef<'a>) -> impl Iterator<Item = WalkEvent<'a>> {
20 generate(Some(WalkEvent::Enter(root)), |pos| { 20 generate(Some(WalkEvent::Enter(root)), move |pos| {
21 let next = match *pos { 21 let next = match *pos {
22 WalkEvent::Enter(node) => match node.first_child() { 22 WalkEvent::Enter(node) => match node.first_child() {
23 Some(child) => WalkEvent::Enter(child), 23 Some(child) => WalkEvent::Enter(child),
24 None => WalkEvent::Exit(node), 24 None => WalkEvent::Exit(node),
25 }, 25 },
26 WalkEvent::Exit(node) => { 26 WalkEvent::Exit(node) => {
27 if node == root {
28 return None;
29 }
27 match node.next_sibling() { 30 match node.next_sibling() {
28 Some(sibling) => WalkEvent::Enter(sibling), 31 Some(sibling) => WalkEvent::Enter(sibling),
29 None => match node.parent() { 32 None => WalkEvent::Exit(node.parent().unwrap()),
30 Some(node) => WalkEvent::Exit(node),
31 None => return None,
32 },
33 } 33 }
34 } 34 }
35 }; 35 };