rename all things

3 files changed, 277 insertions, 0 deletions

diff --git a/crates/ra_syntax/src/algo/mod.rs b/crates/ra_syntax/src/algo/mod.rs
new file mode 100644
index 000000000..7287f5bb2
--- /dev/null
+++ b/crates/ra_syntax/src/algo/mod.rs
@@ -0,0 +1,129 @@
+pub mod walk;
+pub mod visit;
+
+use {
+    SyntaxNodeRef, TextUnit, TextRange,
+    text_utils::{contains_offset_nonstrict, is_subrange},
+};
+
+pub fn find_leaf_at_offset(node: SyntaxNodeRef, offset: TextUnit) -> LeafAtOffset {
+    let range = node.range();
+    assert!(
+        contains_offset_nonstrict(range, offset),
+        "Bad offset: range {:?} offset {:?}", range, offset
+    );
+    if range.is_empty() {
+        return LeafAtOffset::None;
+    }
+
+    if node.is_leaf() {
+        return LeafAtOffset::Single(node);
+    }
+
+    let mut children = node.children()
+        .filter(|child| {
+            let child_range = child.range();
+            !child_range.is_empty() && contains_offset_nonstrict(child_range, offset)
+        });
+
+    let left = children.next().unwrap();
+    let right = children.next();
+    assert!(children.next().is_none());
+    return if let Some(right) = right {
+        match (find_leaf_at_offset(left, offset), find_leaf_at_offset(right, offset)) {
+            (LeafAtOffset::Single(left), LeafAtOffset::Single(right)) =>
+                LeafAtOffset::Between(left, right),
+            _ => unreachable!()
+        }
+    } else {
+        find_leaf_at_offset(left, offset)
+    };
+}
+
+#[derive(Clone, Copy, Debug)]
+pub enum LeafAtOffset<'a> {
+    None,
+    Single(SyntaxNodeRef<'a>),
+    Between(SyntaxNodeRef<'a>, SyntaxNodeRef<'a>)
+}
+
+impl<'a> LeafAtOffset<'a> {
+    pub fn right_biased(self) -> Option<SyntaxNodeRef<'a>> {
+        match self {
+            LeafAtOffset::None => None,
+            LeafAtOffset::Single(node) => Some(node),
+            LeafAtOffset::Between(_, right) => Some(right)
+        }
+    }
+
+    pub fn left_biased(self) -> Option<SyntaxNodeRef<'a>> {
+        match self {
+            LeafAtOffset::None => None,
+            LeafAtOffset::Single(node) => Some(node),
+            LeafAtOffset::Between(left, _) => Some(left)
+        }
+    }
+}
+
+impl<'f> Iterator for LeafAtOffset<'f> {
+    type Item = SyntaxNodeRef<'f>;
+
+    fn next(&mut self) -> Option<SyntaxNodeRef<'f>> {
+        match *self {
+            LeafAtOffset::None => None,
+            LeafAtOffset::Single(node) => { *self = LeafAtOffset::None; Some(node) }
+            LeafAtOffset::Between(left, right) => { *self = LeafAtOffset::Single(right); Some(left) }
+        }
+    }
+}
+
+pub fn find_covering_node(root: SyntaxNodeRef, range: TextRange) -> SyntaxNodeRef {
+    assert!(is_subrange(root.range(), range));
+    let (left, right) = match (
+        find_leaf_at_offset(root, range.start()).right_biased(),
+        find_leaf_at_offset(root, range.end()).left_biased()
+    ) {
+        (Some(l), Some(r)) => (l, r),
+        _ => return root
+    };
+
+    common_ancestor(left, right)
+}
+
+pub fn ancestors<'a>(node: SyntaxNodeRef<'a>) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
+    generate(Some(node), |&node| node.parent())
+}
+
+#[derive(Debug)]
+pub enum Direction {
+    Forward,
+    Backward,
+}
+
+pub fn siblings<'a>(
+    node: SyntaxNodeRef<'a>,
+    direction: Direction
+) -> impl Iterator<Item=SyntaxNodeRef<'a>> {
+    generate(Some(node), move |&node| match direction {
+        Direction::Forward => node.next_sibling(),
+        Direction::Backward => node.prev_sibling(),
+    })
+}
+
+fn common_ancestor<'a>(n1: SyntaxNodeRef<'a>, n2: SyntaxNodeRef<'a>) -> SyntaxNodeRef<'a> {
+    for p in ancestors(n1) {
+        if ancestors(n2).any(|a| a == p) {
+            return p;
+        }
+    }
+    panic!("Can't find common ancestor of {:?} and {:?}", n1, n2)
+}
+
+pub fn generate<T>(seed: Option<T>, step: impl Fn(&T) -> Option<T>) -> impl Iterator<Item=T> {
+    ::itertools::unfold(seed, move |slot| {
+        slot.take().map(|curr| {
+            *slot = step(&curr);
+            curr
+        })
+    })
+}
diff --git a/crates/ra_syntax/src/algo/visit.rs b/crates/ra_syntax/src/algo/visit.rs
new file mode 100644
index 000000000..9f1c127c7
--- /dev/null
+++ b/crates/ra_syntax/src/algo/visit.rs
@@ -0,0 +1,110 @@
+use std::marker::PhantomData;
+use {SyntaxNodeRef, AstNode};
+
+
+pub fn visitor<'a, T>() -> impl Visitor<'a, Output=T> {
+    EmptyVisitor { ph: PhantomData }
+}
+
+pub fn visitor_ctx<'a, T, C>(ctx: C) -> impl VisitorCtx<'a, Output=T, Ctx=C> {
+    EmptyVisitorCtx { ph: PhantomData, ctx }
+}
+
+pub trait Visitor<'a>: Sized {
+    type Output;
+    fn accept(self, node: SyntaxNodeRef<'a>) -> Option<Self::Output>;
+    fn visit<N, F>(self, f: F) -> Vis<Self, N, F>
+        where N: AstNode<'a>,
+              F: FnOnce(N) -> Self::Output,
+    {
+        Vis { inner: self, f, ph: PhantomData }
+    }
+}
+
+pub trait VisitorCtx<'a>: Sized {
+    type Output;
+    type Ctx;
+    fn accept(self, node: SyntaxNodeRef<'a>) -> Result<Self::Output, Self::Ctx>;
+    fn visit<N, F>(self, f: F) -> VisCtx<Self, N, F>
+        where N: AstNode<'a>,
+              F: FnOnce(N, Self::Ctx) -> Self::Output,
+    {
+        VisCtx { inner: self, f, ph: PhantomData }
+    }
+}
+
+#[derive(Debug)]
+struct EmptyVisitor<T> {
+    ph: PhantomData<fn() -> T>
+}
+
+impl<'a, T> Visitor<'a> for EmptyVisitor<T> {
+    type Output = T;
+
+    fn accept(self, _node: SyntaxNodeRef<'a>) -> Option<T> {
+        None
+    }
+}
+
+#[derive(Debug)]
+struct EmptyVisitorCtx<T, C> {
+    ctx: C,
+    ph: PhantomData<fn() -> T>,
+}
+
+impl<'a, T, C> VisitorCtx<'a> for EmptyVisitorCtx<T, C> {
+    type Output = T;
+    type Ctx = C;
+
+    fn accept(self, _node: SyntaxNodeRef<'a>) -> Result<T, C> {
+        Err(self.ctx)
+    }
+}
+
+#[derive(Debug)]
+pub struct Vis<V, N, F> {
+    inner: V,
+    f: F,
+    ph: PhantomData<fn(N)>,
+}
+
+impl<'a, V, N, F> Visitor<'a> for Vis<V, N, F>
+    where
+        V: Visitor<'a>,
+        N: AstNode<'a>,
+        F: FnOnce(N) -> <V as Visitor<'a>>::Output,
+{
+    type Output = <V as Visitor<'a>>::Output;
+
+    fn accept(self, node: SyntaxNodeRef<'a>) -> Option<Self::Output> {
+        let Vis { inner, f, .. } = self;
+        inner.accept(node).or_else(|| N::cast(node).map(f))
+    }
+}
+
+#[derive(Debug)]
+pub struct VisCtx<V, N, F> {
+    inner: V,
+    f: F,
+    ph: PhantomData<fn(N)>,
+}
+
+impl<'a, V, N, F> VisitorCtx<'a> for VisCtx<V, N, F>
+    where
+        V: VisitorCtx<'a>,
+        N: AstNode<'a>,
+        F: FnOnce(N, <V as VisitorCtx<'a>>::Ctx) -> <V as VisitorCtx<'a>>::Output,
+{
+    type Output = <V as VisitorCtx<'a>>::Output;
+    type Ctx = <V as VisitorCtx<'a>>::Ctx;
+
+    fn accept(self, node: SyntaxNodeRef<'a>) -> Result<Self::Output, Self::Ctx> {
+        let VisCtx { inner, f, .. } = self;
+        inner.accept(node).or_else(|ctx|
+            match N::cast(node) {
+                None => Err(ctx),
+                Some(node) => Ok(f(node, ctx))
+            }
+        )
+    }
+}
diff --git a/crates/ra_syntax/src/algo/walk.rs b/crates/ra_syntax/src/algo/walk.rs
new file mode 100644
index 000000000..536ee705f
--- /dev/null
+++ b/crates/ra_syntax/src/algo/walk.rs
@@ -0,0 +1,38 @@
+use {
+    SyntaxNodeRef,
+    algo::generate,
+};
+
+pub fn preorder<'a>(root: SyntaxNodeRef<'a>) -> impl Iterator<Item = SyntaxNodeRef<'a>> {
+    walk(root).filter_map(|event| match event {
+        WalkEvent::Enter(node) => Some(node),
+        WalkEvent::Exit(_) => None,
+    })
+}
+
+#[derive(Debug, Copy, Clone)]
+pub enum WalkEvent<'a> {
+    Enter(SyntaxNodeRef<'a>),
+    Exit(SyntaxNodeRef<'a>),
+}
+
+pub fn walk<'a>(root: SyntaxNodeRef<'a>) -> impl Iterator<Item = WalkEvent<'a>> {
+    generate(Some(WalkEvent::Enter(root)), move |pos| {
+        let next = match *pos {
+            WalkEvent::Enter(node) => match node.first_child() {
+                Some(child) => WalkEvent::Enter(child),
+                None => WalkEvent::Exit(node),
+            },
+            WalkEvent::Exit(node) => {
+                if node == root {
+                    return None;
+                }
+                match node.next_sibling() {
+                    Some(sibling) => WalkEvent::Enter(sibling),
+                    None => WalkEvent::Exit(node.parent().unwrap()),
+                }
+            }
+        };
+        Some(next)
+    })
+}