Introduce EOF token

src/parser/event_parser/grammar.rs

@@ -1,5 +1,6 @@
 use super::parser::Parser;
 use {SyntaxKind};
+use tree::EOF;
 use syntax_kinds::*;
 
 // Items //
@@ -18,11 +19,7 @@ pub(crate) fn file(p: &mut Parser) {
 }
 
 fn item_first(p: &Parser) -> bool {
-    let current = match p.current() {
-        Some(c) => c,
-        None => return false,
-    };
-    match current {
+    match p.current() {
         STRUCT_KW | FN_KW => true,
         _ => false,
     }
@@ -79,7 +76,7 @@ fn visibility(_: &mut Parser) {
 // Error recovery and high-order utils //
 
 fn node_if<F: FnOnce(&mut Parser)>(p: &mut Parser, first: SyntaxKind, node_kind: SyntaxKind, rest: F) -> bool {
-    p.current_is(first) && { node(p, node_kind, |p| { p.bump(); rest(p); }); true }
+    p.current() == first && { node(p, node_kind, |p| { p.bump(); rest(p); }); true }
 }
 
 fn node<F: FnOnce(&mut Parser)>(p: &mut Parser, node_kind: SyntaxKind, rest: F) {
@@ -95,7 +92,7 @@ fn many<F: Fn(&mut Parser) -> bool>(p: &mut Parser, f: F) {
 fn comma_list<F: Fn(&mut Parser) -> bool>(p: &mut Parser, f: F) {
     many(p, |p| {
         f(p);
-        if p.is_eof() {
+        if p.current() == EOF {
             false
         } else {
             p.expect(COMMA);
@@ -119,7 +116,7 @@ where
             f(p);
             return true;
         }
-        if p.is_eof() {
+        if p.current() == EOF {
             if skipped {
                 p.finish();
             }
@@ -131,18 +128,14 @@ where
                 .message(message)
                 .emit();
         }
-        p.bump().unwrap();
+        p.bump();
         skipped = true;
     }
 }
 
 impl<'p> Parser<'p> {
-    fn current_is(&self, kind: SyntaxKind) -> bool {
-        self.current() == Some(kind)
-    }
-
     pub(crate) fn expect(&mut self, kind: SyntaxKind) -> bool {
-        if self.current_is(kind) {
+        if self.current() == kind {
             self.bump();
             true
         } else {
@@ -154,7 +147,7 @@ impl<'p> Parser<'p> {
     }
 
     fn optional(&mut self, kind: SyntaxKind) {
-        if self.current_is(kind) {
+        if self.current() == kind {
             self.bump();
         }
     }

src/parser/event_parser/parser.rs

@@ -2,8 +2,7 @@ use {Token, SyntaxKind, TextUnit};
 use super::{Event};
 use super::super::is_insignificant;
 use syntax_kinds::{L_CURLY, R_CURLY, ERROR};
-
-pub(crate) const EOF: SyntaxKind = SyntaxKind(10000);
+use tree::EOF;
 
 
 pub(crate) struct Parser<'t> {
@@ -46,19 +45,22 @@ impl<'t> Parser<'t> {
     }
 
     pub(crate) fn into_events(self) -> Vec<Event> {
-        assert!(self.is_eof());
+        assert!(self.curly_limit.is_none());
+        assert!(self.current() == EOF);
         self.events
     }
 
-    pub(crate) fn is_eof(&self) -> bool {
+    pub(crate) fn current(&self) -> SyntaxKind {
         if self.pos == self.tokens.len() {
-            return true
+            return EOF;
         }
-        if let Some(limit) = self.curly_limit {
         let token = self.tokens[self.pos];
-            return limit == self.curly_level && token.kind == R_CURLY;
+        if let Some(limit) = self.curly_limit {
+            if limit == self.curly_level && token.kind == R_CURLY {
+                return EOF
             }
-        false
+        }
+        token.kind
     }
 
     pub(crate) fn start(&mut self, kind: SyntaxKind) {
@@ -73,24 +75,17 @@ impl<'t> Parser<'t> {
         ErrorBuilder::new(self)
     }
 
-    pub(crate) fn current(&self) -> Option<SyntaxKind> {
-        if self.is_eof() {
-            return None;
-        }
-        let token = self.tokens[self.pos];
-        Some(token.kind)
-    }
-
-    pub(crate) fn bump(&mut self) -> Option<SyntaxKind> {
-        let kind = self.current()?;
+    pub(crate) fn bump(&mut self) -> SyntaxKind {
+        let kind = self.current();
         match kind {
             L_CURLY => self.curly_level += 1,
             R_CURLY => self.curly_level -= 1,
+            EOF => return EOF,
             _ => (),
         }
         self.pos += 1;
         self.event(Event::Token { kind, n_raw_tokens: 1 });
-        Some(kind)
+        kind
     }
 
     pub(crate) fn lookahead(&self, kinds: &[SyntaxKind]) -> bool {
@@ -114,7 +109,7 @@ impl<'t> Parser<'t> {
         if !self.expect(R_CURLY) {
             self.start(ERROR);
             while self.curly_level > old_level {
-                if self.bump().is_none() {
+                if self.bump() == EOF {
                     break;
                 }
             }

src/tree/mod.rs

@@ -10,8 +10,16 @@ pub use self::file_builder::{FileBuilder, Sink};
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct SyntaxKind(pub(crate) u32);
 
+pub(crate) const EOF: SyntaxKind = SyntaxKind(10000);
+pub(crate) const EOF_INFO: SyntaxInfo = SyntaxInfo {
+    name: "EOF"
+};
+
 impl SyntaxKind {
     fn info(self) -> &'static SyntaxInfo {
+        if self == EOF {
+            return &EOF_INFO;
+        }
         syntax_info(self)
     }
 }