2 files changed, 77 insertions, 6 deletions

diff --git a/src/tree/file_builder.rs b/src/tree/file_builder.rs
index da8b8f824..83aa4186f 100644
--- a/src/tree/file_builder.rs
+++ b/src/tree/file_builder.rs
@@ -1,5 +1,5 @@
 use {SyntaxKind, TextUnit, TextRange};
-use super::{NodeData, NodeIdx, File};
+use super::{NodeData, SyntaxErrorData, NodeIdx, File};
 
 pub trait Sink {
     fn leaf(&mut self, kind: SyntaxKind, len: TextUnit);
@@ -11,6 +11,7 @@ pub trait Sink {
 pub struct FileBuilder {
     text: String,
     nodes: Vec<NodeData>,
+    errors: Vec<SyntaxErrorData>,
     in_progress: Vec<(NodeIdx, Option<NodeIdx>)>, // (parent, last_child)
     pos: TextUnit,
 }
@@ -58,6 +59,7 @@ impl FileBuilder {
         FileBuilder {
             text,
             nodes: Vec::new(),
+            errors: Vec::new(),
             in_progress: Vec::new(),
             pos: TextUnit::new(0),
         }
@@ -75,6 +77,7 @@ impl FileBuilder {
         File {
             text: self.text,
             nodes: self.nodes,
+            errors: self.errors,
         }
     }
 
diff --git a/src/tree/mod.rs b/src/tree/mod.rs
index 7a5d429a3..00d33cbc7 100644
--- a/src/tree/mod.rs
+++ b/src/tree/mod.rs
@@ -36,6 +36,7 @@ pub struct Token {
 pub struct File {
         text: String,
         nodes: Vec<NodeData>,
+        errors: Vec<SyntaxErrorData>,
 }
 
 impl File {
@@ -72,6 +73,14 @@ impl<'f> Node<'f> {
                 Children { next: self.as_node(self.data().first_child) }
         }
 
+        pub fn SyntaxErrors(&self) -> SyntaxErrors<'f> {
+                let pos = self.file.errors.iter().position(|e| e.node == self.idx);
+                let next = pos
+                        .map(|i| ErrorIdx(i as u32))
+                        .map(|idx| SyntaxError { file: self.file, idx });
+                SyntaxErrors { next }
+        }
+
         fn data(&self) -> &'f NodeData {
                 &self.file.nodes[self.idx]
         }
@@ -81,7 +90,41 @@ impl<'f> Node<'f> {
         }
 }
 
+impl<'f> fmt::Debug for Node<'f> {
+        fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
+                write!(fmt, "{:?}@{:?}", self.kind(), self.range())
+        }
+}
 
+#[derive(Clone, Copy)]
+pub struct SyntaxError<'f> {
+        file: &'f File,
+        idx: ErrorIdx,
+}
+
+impl<'f> SyntaxError<'f> {
+        pub fn message(&self) -> &'f str {
+                self.data().message.as_str()
+        }
+
+        fn data(&self) -> &'f SyntaxErrorData {
+                &self.file.errors[self.idx]
+        }
+
+        fn next(&self) -> Option<SyntaxError<'f>> {
+                if self.file.errors.len() == self.idx.0 as usize {
+                        return None;
+                }
+                let result = SyntaxError {
+                        file: self.file,
+                        idx: ErrorIdx(self.idx.0 + 1)
+                };
+                if result.data().node != self.data().node {
+                        return None;
+                }
+                Some(result)
+        }
+}
 
 pub struct Children<'f> {
         next: Option<Node<'f>>,
@@ -97,7 +140,22 @@ impl<'f> Iterator for Children<'f> {
         }
 }
 
-#[derive(Clone, Copy)]
+pub struct SyntaxErrors<'f> {
+        next: Option<SyntaxError<'f>>,
+}
+
+impl<'f> Iterator for SyntaxErrors<'f> {
+        type Item = SyntaxError<'f>;
+
+        fn next(&mut self) -> Option<SyntaxError<'f>> {
+                let next = self.next;
+                self.next = next.as_ref().and_then(SyntaxError::next);
+                next
+        }
+}
+
+
+#[derive(Clone, Copy, PartialEq, Eq)]
 struct NodeIdx(u32);
 
 struct NodeData {
@@ -122,8 +180,18 @@ impl ::std::ops::IndexMut<NodeIdx> for Vec<NodeData> {
         }
 }
 
-impl<'f> fmt::Debug for Node<'f> {
-        fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-                write!(fmt, "{:?}@{:?}", self.kind(), self.range())
+#[derive(Clone, Copy)]
+struct ErrorIdx(u32);
+
+struct SyntaxErrorData {
+        node: NodeIdx,
+        message: String,
+}
+
+impl ::std::ops::Index<ErrorIdx> for Vec<SyntaxErrorData> {
+        type Output = SyntaxErrorData;
+
+        fn index(&self, ErrorIdx(idx): ErrorIdx) -> &SyntaxErrorData {
+                &self[idx as usize]
         }
-}
\ No newline at end of file
+}