8 files changed, 62 insertions, 14 deletions

diff --git a/src/algo/walk.rs b/src/algo/walk.rs
index a50ec2a09..ad0f2d8fb 100644
--- a/src/algo/walk.rs
+++ b/src/algo/walk.rs
@@ -6,7 +6,6 @@ pub fn preorder<'a>(root: SyntaxNodeRef<'a>) -> impl Iterator<Item = SyntaxNodeR
         WalkEvent::Exit(_) => None,
     })
 }
-
 #[derive(Debug, Copy, Clone)]
 pub enum WalkEvent<'a> {
     Enter(SyntaxNodeRef<'a>),
diff --git a/src/ast.rs b/src/ast.rs
index 48e1d23ac..caf5fb7ef 100644
--- a/src/ast.rs
+++ b/src/ast.rs
@@ -9,7 +9,7 @@ pub struct File<R: TreeRoot = Arc<SyntaxRoot>> {
 impl File<Arc<SyntaxRoot>> {
     pub fn parse(text: &str) -> Self {
         File {
-            syntax: ::parse(text.to_owned()),
+            syntax: ::parse(text),
         }
     }
 }
diff --git a/src/lib.rs b/src/lib.rs
index 8f25de9a4..611b87492 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -45,7 +45,7 @@ pub use {
     yellow::{SyntaxNode, SyntaxNodeRef, SyntaxRoot, TreeRoot},
 };
 
-pub fn parse(text: String) -> SyntaxNode {
+pub fn parse(text: &str) -> SyntaxNode {
     let tokens = tokenize(&text);
     parser_impl::parse::<yellow::GreenBuilder>(text, &tokens)
 }
diff --git a/src/parser_impl/event.rs b/src/parser_impl/event.rs
index eb5d0a4be..66a0b6fc0 100644
--- a/src/parser_impl/event.rs
+++ b/src/parser_impl/event.rs
@@ -76,7 +76,7 @@ pub(crate) enum Event {
     },
 }
 
-pub(super) fn process(builder: &mut impl Sink, tokens: &[Token], events: Vec<Event>) {
+pub(super) fn process<'a>(builder: &mut impl Sink<'a>, tokens: &[Token], events: Vec<Event>) {
     let mut idx = 0;
 
     let mut holes = Vec::new();
diff --git a/src/parser_impl/mod.rs b/src/parser_impl/mod.rs
index b58094be3..2791c8da5 100644
--- a/src/parser_impl/mod.rs
+++ b/src/parser_impl/mod.rs
@@ -14,10 +14,10 @@ use {
 
 use SyntaxKind::{self, EOF, TOMBSTONE};
 
-pub(crate) trait Sink {
+pub(crate) trait Sink<'a> {
     type Tree;
 
-    fn new(text: String) -> Self;
+    fn new(text: &'a str) -> Self;
 
     fn leaf(&mut self, kind: SyntaxKind, len: TextUnit);
     fn start_internal(&mut self, kind: SyntaxKind);
@@ -27,9 +27,9 @@ pub(crate) trait Sink {
 }
 
 /// Parse a sequence of tokens into the representative node tree
-pub(crate) fn parse<S: Sink>(text: String, tokens: &[Token]) -> S::Tree {
+pub(crate) fn parse<'a, S: Sink<'a>>(text: &'a str, tokens: &[Token]) -> S::Tree {
     let events = {
-        let input = input::ParserInput::new(&text, tokens);
+        let input = input::ParserInput::new(text, tokens);
         let parser_impl = ParserImpl::new(&input);
         let mut parser_api = Parser(parser_impl);
         grammar::file(&mut parser_api);
diff --git a/src/syntax_kinds/generated.rs b/src/syntax_kinds/generated.rs
index 435be781c..cbcd0c4e1 100644
--- a/src/syntax_kinds/generated.rs
+++ b/src/syntax_kinds/generated.rs
@@ -169,6 +169,47 @@ pub enum SyntaxKind {
 use self::SyntaxKind::*;
 
 impl SyntaxKind {
+    pub fn is_keyword(self) -> bool {
+        match self {
+            | USE_KW
+            | FN_KW
+            | STRUCT_KW
+            | ENUM_KW
+            | TRAIT_KW
+            | IMPL_KW
+            | TRUE_KW
+            | FALSE_KW
+            | AS_KW
+            | EXTERN_KW
+            | CRATE_KW
+            | MOD_KW
+            | PUB_KW
+            | SELF_KW
+            | SUPER_KW
+            | IN_KW
+            | WHERE_KW
+            | FOR_KW
+            | LOOP_KW
+            | WHILE_KW
+            | IF_KW
+            | ELSE_KW
+            | MATCH_KW
+            | CONST_KW
+            | STATIC_KW
+            | MUT_KW
+            | UNSAFE_KW
+            | TYPE_KW
+            | REF_KW
+            | LET_KW
+            | MOVE_KW
+            | AUTO_KW
+            | DEFAULT_KW
+            | UNION_KW
+                => true,
+            _ => false
+        }
+    }
+
     pub(crate) fn info(self) -> &'static SyntaxInfo {
         match self {
             SEMI => &SyntaxInfo { name: "SEMI" },
diff --git a/src/syntax_kinds/generated.rs.tera b/src/syntax_kinds/generated.rs.tera
index d719c8312..4e2ee56c3 100644
--- a/src/syntax_kinds/generated.rs.tera
+++ b/src/syntax_kinds/generated.rs.tera
@@ -24,6 +24,16 @@ pub enum SyntaxKind {
 use self::SyntaxKind::*;
 
 impl SyntaxKind {
+    pub fn is_keyword(self) -> bool {
+        match self {
+{%- for kw in concat(a=keywords, b=contextual_keywords) %}
+            | {{kw | upper}}_KW
+{%- endfor %}
+                => true,
+            _ => false
+        }
+    }
+
     pub(crate) fn info(self) -> &'static SyntaxInfo {
         match self {
 {%- for t in concat(a=single_byte_tokens, b=multi_byte_tokens) %}
diff --git a/src/yellow/builder.rs b/src/yellow/builder.rs
index b68ba789e..dbe646cd7 100644
--- a/src/yellow/builder.rs
+++ b/src/yellow/builder.rs
@@ -4,20 +4,18 @@ use {
     SyntaxKind, TextRange, TextUnit,
 };
 
-pub(crate) struct GreenBuilder {
-    text: String,
+pub(crate) struct GreenBuilder<'a> {
+    text: &'a str,
     stack: Vec<GreenNodeBuilder>,
     pos: TextUnit,
     root: Option<GreenNode>,
     errors: Vec<SyntaxError>,
 }
 
-impl GreenBuilder {}
-
-impl Sink for GreenBuilder {
+impl<'a> Sink<'a> for GreenBuilder<'a> {
     type Tree = SyntaxNode;
 
-    fn new(text: String) -> Self {
+    fn new(text: &'a str) -> Self {
         GreenBuilder {
             text,
             stack: Vec::new(),