move parser to a separate crate

crates/ra_parser/src/lib.rs

@@ -0,0 +1,64 @@
+#[macro_use]
+mod token_set;
+mod syntax_kind;
+mod event;
+mod parser;
+mod grammar;
+
+pub(crate) use token_set::TokenSet;
+
+pub use syntax_kind::SyntaxKind;
+
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct ParseError(pub String);
+
+/// `TreeSink` abstracts details of a particular syntax tree implementation.
+pub trait TreeSink {
+    /// Adds new leaf to the current branch.
+    fn leaf(&mut self, kind: SyntaxKind, n_tokens: u8);
+
+    /// Start new branch and make it current.
+    fn start_branch(&mut self, kind: SyntaxKind, root: bool);
+
+    /// Finish current branch and restore previous
+    /// branch as current.
+    fn finish_branch(&mut self, root: bool);
+
+    fn error(&mut self, error: ParseError);
+}
+
+/// `TokenSource` abstracts the source of the tokens parser operates one.
+///
+/// Hopefully this will allow us to treat text and token trees in the same way!
+pub trait TokenSource {
+    fn token_kind(&self, pos: usize) -> SyntaxKind;
+    fn is_token_joint_to_next(&self, pos: usize) -> bool;
+    fn is_keyword(&self, pos: usize, kw: &str) -> bool;
+}
+
+pub fn parse(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink) {
+    let mut p = parser::Parser::new(token_source);
+    grammar::root(&mut p);
+    let events = p.finish();
+    event::process(tree_sink, events);
+}
+
+pub struct Reparser(fn(&mut parser::Parser));
+
+impl Reparser {
+    pub fn for_node(
+        node: SyntaxKind,
+        first_child: Option<SyntaxKind>,
+        parent: Option<SyntaxKind>,
+    ) -> Option<Reparser> {
+        grammar::reparser(node, first_child, parent).map(Reparser)
+    }
+}
+
+pub fn reparse(token_source: &dyn TokenSource, tree_sink: &mut dyn TreeSink, reparser: Reparser) {
+    let Reparser(r) = reparser;
+    let mut p = parser::Parser::new(token_source);
+    r(&mut p);
+    let events = p.finish();
+    event::process(tree_sink, events);
+}