6 files changed, 150 insertions, 17 deletions

diff --git a/src/lexer/mod.rs b/src/lexer/mod.rs
index f46746bee..7c4259763 100644
--- a/src/lexer/mod.rs
+++ b/src/lexer/mod.rs
@@ -16,6 +16,17 @@ use self::strings::{is_string_literal_start, scan_char, scan_byte_char_or_string
 mod comments;
 use self::comments::{scan_shebang, scan_comment};
 
+pub fn tokenize(text: &str) -> Vec<Token> {
+    let mut text = text;
+    let mut acc = Vec::new();
+    while !text.is_empty() {
+        let token = next_token(text);
+        acc.push(token);
+        let len: u32 = token.len.into();
+        text = &text[len as usize..];
+    }
+    acc
+}
 pub fn next_token(text: &str) -> Token {
     assert!(!text.is_empty());
     let mut ptr = Ptr::new(text);
diff --git a/src/lib.rs b/src/lib.rs
index 3b9dbc8f7..82213e2b3 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,6 +5,6 @@ mod tree;
 mod lexer;
 
 pub mod syntax_kinds;
-pub use text::TextUnit;
+pub use text::{TextUnit, TextRange};
 pub use tree::{SyntaxKind, Token};
-pub use lexer::next_token;
+pub use lexer::{next_token, tokenize};
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
new file mode 100644
index 000000000..da902e2b7
--- /dev/null
+++ b/src/parser/mod.rs
@@ -0,0 +1,5 @@
+use {Token, File};
+
+pub fn parse(tokens: &[Token]) -> File {
+    unimplemented!()
+}
\ No newline at end of file
diff --git a/src/text.rs b/src/text.rs
index c3ef1ac8e..ee0dc8398 100644
--- a/src/text.rs
+++ b/src/text.rs
@@ -56,4 +56,63 @@ impl ops::SubAssign<TextUnit> for TextUnit {
     fn sub_assign(&mut self, rhs: TextUnit) {
         self.0 -= rhs.0
     }
+}
+
+
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct TextRange {
+    start: TextUnit,
+    end: TextUnit,
+}
+
+impl fmt::Debug for TextRange {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        <Self as fmt::Display>::fmt(self, f)
+    }
+}
+
+impl fmt::Display for TextRange {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "[{}; {})", self.start(), self.end())
+    }
+}
+
+
+impl TextRange {
+    pub fn empty() -> TextRange {
+        TextRange::from_to(TextUnit::new(0), TextUnit::new(0))
+    }
+
+    pub fn from_to(from: TextUnit, to: TextUnit) -> TextRange {
+        assert!(from <= to, "Invalid text range [{}; {})", from, to);
+        TextRange { start: from, end: to }
+    }
+
+    pub fn from_len(from: TextUnit, len: TextUnit) -> TextRange {
+        TextRange::from_to(from, from + len)
+    }
+
+    pub fn start(&self) -> TextUnit {
+        self.start
+    }
+
+    pub fn end(&self) -> TextUnit {
+        self.end
+    }
+
+    pub fn len(&self) -> TextUnit {
+        self.end - self.start
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.start() == self.end()
+    }
+}
+
+impl ops::Index<TextRange> for str {
+    type Output = str;
+
+    fn index(&self, index: TextRange) -> &str {
+        &self[index.start().0 as usize..index.end().0 as usize]
+    }
 }
\ No newline at end of file
diff --git a/src/tree.rs b/src/tree.rs
index 0924f38d0..2ac25e795 100644
--- a/src/tree.rs
+++ b/src/tree.rs
@@ -1,4 +1,4 @@
-use text::{TextUnit};
+use text::{TextUnit, TextRange};
 use syntax_kinds::syntax_info;
 
 use std::fmt;
@@ -28,4 +28,74 @@ pub(crate) struct SyntaxInfo {
 pub struct Token {
     pub kind: SyntaxKind,
     pub len: TextUnit,
-}
\ No newline at end of file
+}
+
+pub struct File {
+        text: String,
+        nodes: Vec<NodeData>,
+}
+
+impl File {
+        pub fn root<'f>(&'f self) -> Node<'f> {
+                assert!(!self.nodes.is_empty());
+                Node { file: self, idx: NodeIdx(0) }
+        }
+}
+
+#[derive(Clone, Copy)]
+pub struct Node<'f> {
+        file: &'f File,
+        idx: NodeIdx,
+}
+
+impl<'f> Node<'f> {
+        pub fn kind(&self) -> SyntaxKind {
+                self.data().kind
+        }
+
+        pub fn text(&self) -> &'f str {
+                let range = self.data().range;
+                &self.file.text.as_str()[range]
+        }
+
+        pub fn parent(&self) -> Option<Node<'f>> {
+                self.as_node(self.data().parent)
+        }
+
+        pub fn children(&self) -> Children<'f> {
+                Children { next: self.as_node(self.data().first_child) }
+        }
+
+        fn data(&self) -> &'f NodeData {
+                &self.file.nodes[self.idx.0 as usize]
+        }
+
+        fn as_node(&self, idx: Option<NodeIdx>) -> Option<Node<'f>> {
+                idx.map(|idx| Node { file: self.file, idx })
+        }
+}
+
+pub struct Children<'f> {
+        next: Option<Node<'f>>,
+}
+
+impl<'f> Iterator for Children<'f> {
+        type Item = Node<'f>;
+
+        fn next(&mut self) -> Option<Node<'f>> {
+                let next = self.next;
+                self.next = next.and_then(|node| node.as_node(node.data().next_sibling));
+                next
+        }
+}
+
+#[derive(Clone, Copy)]
+struct NodeIdx(u32);
+
+struct NodeData {
+        kind: SyntaxKind,
+        range: TextRange,
+        parent: Option<NodeIdx>,
+        first_child: Option<NodeIdx>,
+        next_sibling: Option<NodeIdx>,
+}
diff --git a/tests/lexer.rs b/tests/lexer.rs
index 6a9bab66b..beca19c24 100644
--- a/tests/lexer.rs
+++ b/tests/lexer.rs
@@ -7,7 +7,7 @@ use std::path::{PathBuf, Path};
 use std::fs::read_dir;
 use std::fmt::Write;
 
-use libsyntax2::{Token, next_token};
+use libsyntax2::{Token, tokenize};
 
 #[test]
 fn lexer_tests() {
@@ -53,18 +53,6 @@ fn lexer_test_case(path: &Path) {
     assert_diff!(expected, actual, "\n", 0)
 }
 
-fn tokenize(text: &str) -> Vec<Token> {
-    let mut text = text;
-    let mut acc = Vec::new();
-    while !text.is_empty() {
-        let token = next_token(text);
-        acc.push(token);
-        let len: u32 = token.len.into();
-        text = &text[len as usize..];
-    }
-    acc
-}
-
 fn dump_tokens(tokens: &[Token], text: &str) -> String {
     let mut acc = String::new();
     let mut offset = 0;