6 files changed, 60 insertions, 3 deletions

diff --git a/src/lexer/mod.rs b/src/lexer/mod.rs
index 2f8d3a402..65a994327 100644
--- a/src/lexer/mod.rs
+++ b/src/lexer/mod.rs
@@ -17,6 +17,7 @@ use self::strings::{is_string_literal_start, scan_byte_char_or_string, scan_char
 mod comments;
 use self::comments::{scan_comment, scan_shebang};
 
+/// Break a string up into its component tokens
 pub fn tokenize(text: &str) -> Vec<Token> {
     let mut text = text;
     let mut acc = Vec::new();
@@ -28,6 +29,7 @@ pub fn tokenize(text: &str) -> Vec<Token> {
     }
     acc
 }
+/// Get the next token from a string
 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 39b01a1cb..87a9d11ea 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,20 @@
+//! An experimental implementation of [Rust RFC#2256 libsyntax2.0][rfc#2256].
+//!
+//! The intent is to be an IDE-ready parser, i.e. one that offers
+//!
+//! - easy and fast incremental re-parsing,
+//! - graceful handling of errors, and
+//! - maintains all information in the source file.
+//!
+//! For more information, see [the RFC][rfc#2265], or [the working draft][RFC.md].
+//!
+//!   [rfc#2256]: <https://github.com/rust-lang/rfcs/pull/2256>
+//!   [RFC.md]: <https://github.com/matklad/libsyntax2/blob/master/docs/RFC.md>
+
+#![forbid(missing_debug_implementations, unconditional_recursion, future_incompatible)]
+#![deny(bad_style, unsafe_code, missing_docs)]
+//#![warn(unreachable_pub)] // rust-lang/rust#47816
+
 extern crate unicode_xid;
 
 mod text;
@@ -6,17 +23,20 @@ mod lexer;
 mod parser;
 
 #[cfg_attr(rustfmt, rustfmt_skip)]
+#[allow(missing_docs)]
 pub mod syntax_kinds;
 pub use text::{TextRange, TextUnit};
 pub use tree::{File, FileBuilder, Node, Sink, SyntaxKind, Token};
 pub use lexer::{next_token, tokenize};
 pub use parser::parse;
 
+/// Utilities for simple uses of the parser.
 pub mod utils {
     use std::fmt::Write;
 
     use {File, Node};
 
+    /// Parse a file and create a string representation of the resulting parse tree.
     pub fn dump_tree(file: &File) -> String {
         let mut result = String::new();
         go(file.root(), &mut result, 0);
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index d04ed1e75..0f8f2ce0c 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -6,6 +6,7 @@ use tree::TOMBSTONE;
 mod event_parser;
 use self::event_parser::Event;
 
+/// Parse a sequence of tokens into the representative node tree
 pub fn parse(text: String, tokens: &[Token]) -> File {
     let events = event_parser::parse(&text, tokens);
     from_events_to_file(text, tokens, events)
diff --git a/src/text.rs b/src/text.rs
index ac1a54a75..4084bf44e 100644
--- a/src/text.rs
+++ b/src/text.rs
@@ -1,14 +1,17 @@
 use std::fmt;
 use std::ops;
 
+/// An text position in a source file
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct TextUnit(u32);
 
 impl TextUnit {
+    /// The positional offset required for one character
     pub fn len_of_char(c: char) -> TextUnit {
         TextUnit(c.len_utf8() as u32)
     }
 
+    #[allow(missing_docs)]
     pub fn new(val: u32) -> TextUnit {
         TextUnit(val)
     }
@@ -64,6 +67,7 @@ impl ops::SubAssign<TextUnit> for TextUnit {
     }
 }
 
+/// A range of text in a source file
 #[derive(Clone, Copy, PartialEq, Eq)]
 pub struct TextRange {
     start: TextUnit,
@@ -83,10 +87,12 @@ impl fmt::Display for TextRange {
 }
 
 impl TextRange {
+    /// An length-0 range of text
     pub fn empty() -> TextRange {
         TextRange::from_to(TextUnit::new(0), TextUnit::new(0))
     }
 
+    /// The left-inclusive range (`[from..to)`) between to points in the text
     pub fn from_to(from: TextUnit, to: TextUnit) -> TextRange {
         assert!(from <= to, "Invalid text range [{}; {})", from, to);
         TextRange {
@@ -95,22 +101,27 @@ impl TextRange {
         }
     }
 
+    /// The range from some point over some length
     pub fn from_len(from: TextUnit, len: TextUnit) -> TextRange {
         TextRange::from_to(from, from + len)
     }
 
+    /// The starting position of this range
     pub fn start(&self) -> TextUnit {
         self.start
     }
 
+    /// The end position of this range
     pub fn end(&self) -> TextUnit {
         self.end
     }
 
+    /// The length of this range
     pub fn len(&self) -> TextUnit {
         self.end - self.start
     }
 
+    /// Is this range empty of any content?
     pub fn is_empty(&self) -> bool {
         self.start() == self.end()
     }
diff --git a/src/tree/file_builder.rs b/src/tree/file_builder.rs
index 939922cb2..738705f02 100644
--- a/src/tree/file_builder.rs
+++ b/src/tree/file_builder.rs
@@ -1,3 +1,6 @@
+// FIXME(CAD97): I don't understand this mod well enough to stub out docs for the public symbols yet
+#![allow(missing_docs)]
+
 use {SyntaxKind, TextRange, TextUnit};
 use super::{File, NodeData, NodeIdx, SyntaxErrorData};
 
@@ -8,6 +11,7 @@ pub trait Sink {
     fn error(&mut self) -> ErrorBuilder;
 }
 
+#[derive(Debug)]
 pub struct FileBuilder {
     text: String,
     nodes: Vec<NodeData>,
@@ -139,6 +143,7 @@ fn grow(left: &mut TextRange, right: TextRange) {
     *left = TextRange::from_to(left.start(), right.end())
 }
 
+#[derive(Debug)]
 pub struct ErrorBuilder<'f> {
     message: Option<String>,
     builder: &'f mut FileBuilder,
diff --git a/src/tree/mod.rs b/src/tree/mod.rs
index a330caf54..aaf048c73 100644
--- a/src/tree/mod.rs
+++ b/src/tree/mod.rs
@@ -7,6 +7,7 @@ use std::cmp;
 mod file_builder;
 pub use self::file_builder::{FileBuilder, Sink};
 
+/// The kind of syntax node, e.g. `IDENT`, `USE_KW`, or `STRUCT_DEF`.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct SyntaxKind(pub(crate) u32);
 
@@ -37,12 +38,17 @@ pub(crate) struct SyntaxInfo {
     pub name: &'static str,
 }
 
+/// A token of Rust source.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Token {
+    /// The kind of token.
     pub kind: SyntaxKind,
+    /// The length of the token.
     pub len: TextUnit,
 }
 
+/// The contents of a Rust source file.
+#[derive(Debug)]
 pub struct File {
     text: String,
     nodes: Vec<NodeData>,
@@ -50,6 +56,7 @@ pub struct File {
 }
 
 impl File {
+    /// The root node of this source file.
     pub fn root<'f>(&'f self) -> Node<'f> {
         assert!(!self.nodes.is_empty());
         Node {
@@ -59,6 +66,7 @@ impl File {
     }
 }
 
+/// A reference to a token in a Rust source file.
 #[derive(Clone, Copy)]
 pub struct Node<'f> {
     file: &'f File,
@@ -66,28 +74,34 @@ pub struct Node<'f> {
 }
 
 impl<'f> Node<'f> {
+    /// The kind of the token at this node.
     pub fn kind(&self) -> SyntaxKind {
         self.data().kind
     }
 
+    /// The text range covered by the token at this node.
     pub fn range(&self) -> TextRange {
         self.data().range
     }
 
+    /// The text at this node.
     pub fn text(&self) -> &'f str {
         &self.file.text.as_str()[self.range()]
     }
 
+    /// The parent node to this node.
     pub fn parent(&self) -> Option<Node<'f>> {
         self.as_node(self.data().parent)
     }
 
+    /// The children nodes of this node.
     pub fn children(&self) -> Children<'f> {
         Children {
             next: self.as_node(self.data().first_child),
         }
     }
 
+    /// Any errors contained in this node.
     pub fn errors(&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 {
@@ -123,7 +137,7 @@ impl<'f> cmp::PartialEq<Node<'f>> for Node<'f> {
 
 impl<'f> cmp::Eq for Node<'f> {}
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
 pub struct SyntaxError<'f> {
     file: &'f File,
     idx: ErrorIdx,
@@ -162,6 +176,7 @@ impl<'f> SyntaxError<'f> {
     }
 }
 
+#[derive(Debug)]
 pub struct Children<'f> {
     next: Option<Node<'f>>,
 }
@@ -176,6 +191,7 @@ impl<'f> Iterator for Children<'f> {
     }
 }
 
+#[derive(Debug)]
 pub struct SyntaxErrors<'f> {
     next: Option<SyntaxError<'f>>,
 }
@@ -190,9 +206,10 @@ impl<'f> Iterator for SyntaxErrors<'f> {
     }
 }
 
-#[derive(Clone, Copy, PartialEq, Eq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 struct NodeIdx(u32);
 
+#[derive(Debug)]
 struct NodeData {
     kind: SyntaxKind,
     range: TextRange,
@@ -215,9 +232,10 @@ impl ::std::ops::IndexMut<NodeIdx> for Vec<NodeData> {
     }
 }
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, Debug)]
 struct ErrorIdx(u32);
 
+#[derive(Debug)]
 struct SyntaxErrorData {
     node: NodeIdx,
     message: String,