update README, fix for getter on optional rule

Author: rrevenantt

README.md

@@ -8,32 +8,39 @@ and [tests/my_tests.rs](tests/my_test.rs) for actual usage examples
 
 ### Implementation status
 
-Everything is implemented, business logic is quite stable and well tested, but user facing 
+Everything is implemented, "business" logic is quite stable and well tested, but user facing 
 API is not very robust yet an very likely will have some changes.
 
+For now development is going on in this repository 
+but eventually it will be merged to main ANTLR4 repo
+
 Currently requires nightly version of rust. 
 This very likely will be the case until `specialization`,`try_blocks` and `unsize` features are stabilized. 
 
-Remaining core things:
-- [ ] Documentation
-  - [ ] Quite some things are already documented but still far from perfect
-- [ ] API stabilization
-  - [ ] Rust api guidelines compliance  
-  - [ ] more tests for API because it is quite different from Java
-- [ ] Code quality
-  - [ ] Rustfmt fails to run currently
-  - [ ] Clippy sanitation 
-  - [ ] Not all warning are fixed
-  
-See tracking [issue](https://github.com/antlr/antlr4/issues/1839) for more info
-  
-### Additional improvements:
+Remaining things before merge:
+ - API stabilization
+   - [ ] Rust api guidelines compliance  
+   - [ ] more tests for API because it is quite different from Java
  - make parsing zero copy(i.e. use &str(or Cow) instead String in token and &Token in tree nodes)
+ - more generic `PredictionContext`
+ - generic over ownership for string
  - profiling and performance optimizations
- - use & instead of Rc for nodes in parser
+ - generate enum for labeled alternatives without redundant `Error` option
+ - ? option to generate fields instead of getters by default
+
+Can be done after merge: 
+ - Documentation
+   - [ ] Quite some things are already documented but still far from perfect
+ - Code quality
+   - [ ] Rustfmt fails to run currently
+   - [ ] Clippy sanitation 
+   - [ ] Not all warning are fixed
  - visitor
- - build.rs integration example
+ - build.rs integration + example
  - run rustfmt on generated parser
+###### Long term improvements
+ - use & instead of Rc for nodes in parser
+ (requires GAT, otherwise it would be a problem for users that want ownership for parse tree)
  - support stable rust
  - support no_std(although alloc would still be required)  
 

grammars/Perf.g4

@@ -0,0 +1,18 @@
+grammar Perf;
+
+stat : expr ';'
+     | expr '.'
+     ;
+
+expr
+	: ID
+	| 'not' expr
+	| expr 'and' expr
+    | expr 'or' expr
+    | '(' ID ')' expr
+    | expr '?' expr ':' expr
+    | 'between' expr 'and' expr
+	;
+
+ID: [a-zA-Z_][a-zA-Z_0-9]*;
+WS: [ \t\n\r\f]+ -> skip;

src/atn_state.rs

@@ -63,6 +63,8 @@ pub enum ATNBlockStart {
 
 pub type ATNStateRef = usize;
 
+
+// todo no need for trait here, it is too slow for hot code
 pub trait ATNState: Sync + Send + Debug {
     fn has_epsilon_only_transitions(&self) -> bool;
 

src/dfa_state.rs

@@ -45,12 +45,6 @@ impl PartialEq for DFAState {
     }
 }
 
-//impl Hash for *DFAState{
-//    fn hash<H: Hasher>(&self, state: &mut H) {
-//        unsafe{ (**self).hash(state) }
-//    }
-//}
-
 impl Hash for DFAState {
     fn hash<H: Hasher>(&self, state: &mut H) {
         self.configs.hash(state);

src/parser_rule_context.rs

@@ -41,13 +41,13 @@ pub trait ParserRuleContext: RuleContext + CustomRuleContext + ParseTree + Any +
     fn enter_rule(&self, listener: &mut dyn Any);
     fn exit_rule(&self, listener: &mut dyn Any);
 
-    fn child_of_type<T: ParserRuleContext>(&self, pos: usize) -> Rc<T> where Self: Sized {
+    fn child_of_type<T: ParserRuleContext>(&self, pos: usize) -> Option<Rc<T>> where Self: Sized {
         let result = self.get_children().iter()
             .filter(|&it| it.deref().type_id() == TypeId::of::<T>())
-            .nth(pos).unwrap()
-            .clone();
+            .nth(pos)
+            .cloned();
 
-        cast_rc(result)
+        result.map(cast_rc)
     }
 
     fn children_of_type<T: ParserRuleContext>(&self) -> Vec<Rc<T>> where Self: Sized {

src/transition.rs

@@ -47,6 +47,7 @@ pub enum TransitionType {
     TRANSITION_PRECEDENCE,
 }
 
+// todo remove trait because it is too slow
 /// Transition between ATNStates
 pub trait Transition: Sync + Send + Debug + Any {
     fn get_target(&self) -> ATNStateRef;

tests/gen/csvlexer.rs

@@ -32,23 +32,23 @@ pub const WS: isize = 4;
 pub const TEXT: isize = 5;
 pub const STRING: isize = 6;
 pub const channelNames: [&'static str; 0 + 2] = [
-    "DEFAULT_TOKEN_CHANNEL", "HIDDEN"
+	"DEFAULT_TOKEN_CHANNEL", "HIDDEN"
 ];
 
 pub const modeNames: [&'static str; 1] = [
-    "DEFAULT_MODE"
+	"DEFAULT_MODE"
 ];
 
 pub const ruleNames: [&'static str; 6] = [
-    "T__0", "T__1", "T__2", "WS", "TEXT", "STRING"
+	"T__0", "T__1", "T__2", "WS", "TEXT", "STRING"
 ];
 
 
 pub const _LITERAL_NAMES: [Option<&'static str>; 4] = [
-    None, Some("','"), Some("'\r'"), Some("'\n'")
+	None, Some("','"), Some("'\r'"), Some("'\n'")
 ];
 pub const _SYMBOLIC_NAMES: [Option<&'static str>; 7] = [
-    None, None, None, None, Some("WS"), Some("TEXT"), Some("STRING")
+	None, None, None, None, Some("WS"), Some("TEXT"), Some("STRING")
 ];
 lazy_static! {
 	    static ref _shared_context_cache: Arc<PredictionContextCache> = Arc::new(PredictionContextCache::new());
@@ -57,22 +57,22 @@ lazy_static! {
 
 
 pub struct CSVLexer {
-    base: BaseLexer<CSVLexerActions>,
+	base: BaseLexer<CSVLexerActions>,
 //	static { RuntimeMetaData.checkVersion("4.8", RuntimeMetaData.VERSION); }
 }
 
 impl Deref for CSVLexer {
-    type Target = BaseLexer<CSVLexerActions>;
+	type Target = BaseLexer<CSVLexerActions>;
 
-    fn deref(&self) -> &Self::Target {
-        &self.base
-    }
+	fn deref(&self) -> &Self::Target {
+		&self.base
+	}
 }
 
 impl DerefMut for CSVLexer {
-    fn deref_mut(&mut self) -> &mut Self::Target {
-        &mut self.base
-    }
+	fn deref_mut(&mut self) -> &mut Self::Target {
+		&mut self.base
+	}
 }
 
 
@@ -90,29 +90,29 @@ impl CSVLexer {
 
     fn add_error_listener(&mut self, _listener: Box<dyn ErrorListener>) {
         self.base.add_error_listener(_listener);
-    }
+	}
 
-    fn remove_error_listeners(&mut self) {
-        self.base.remove_error_listeners()
-    }
+	fn remove_error_listeners(&mut self) {
+		self.base.remove_error_listeners()
+	}
 
-    fn get_grammar_file_name(&self) -> &'static str {
-        "CSVLexer.g4"
-    }
+	fn get_grammar_file_name(&self) -> &'static str {
+		"CSVLexer.g4"
+	}
 
-    pub fn new(input: Box<dyn CharStream>) -> Self {
-        antlr_rust::recognizer::check_version("0", "1");
-        Self {
-            base: BaseLexer::new_base_lexer(
-                input,
-                LexerATNSimulator::new_lexer_atnsimulator(
-                    _ATN.clone(),
-                    _decision_to_DFA.clone(),
-                    _shared_context_cache.clone(),
-                ),
-                Box::new(CSVLexerActions {}),
-            )
-        }
+	pub fn new(input: Box<dyn CharStream>) -> Self {
+		antlr_rust::recognizer::check_version("0", "1");
+		Self {
+			base: BaseLexer::new_base_lexer(
+				input,
+				LexerATNSimulator::new_lexer_atnsimulator(
+					_ATN.clone(),
+					_decision_to_DFA.clone(),
+					_shared_context_cache.clone(),
+				),
+				Box::new(CSVLexerActions {}),
+			)
+		}
 	}
 }
 
@@ -125,35 +125,35 @@ impl LexerRecog for CSVLexerActions {}
 impl Recognizer for CSVLexerActions {}
 
 impl Actions for CSVLexerActions {
-    type Recog = BaseLexer<CSVLexerActions>;
+	type Recog = BaseLexer<CSVLexerActions>;
 }
 
 impl CSVLexerActions {}
 
 impl TokenSource for CSVLexer {
-    fn next_token(&mut self) -> Box<dyn Token> {
-        self.base.next_token()
-    }
+	fn next_token(&mut self) -> Box<dyn Token> {
+		self.base.next_token()
+	}
 
-    fn get_line(&self) -> isize {
-        self.base.get_line()
-    }
+	fn get_line(&self) -> isize {
+		self.base.get_line()
+	}
 
-    fn get_char_position_in_line(&self) -> isize {
-        self.base.get_char_position_in_line()
-    }
+	fn get_char_position_in_line(&self) -> isize {
+		self.base.get_char_position_in_line()
+	}
 
-    fn get_input_stream(&mut self) -> &mut dyn CharStream {
-        self.base.get_input_stream()
-    }
+	fn get_input_stream(&mut self) -> &mut dyn CharStream {
+		self.base.get_input_stream()
+	}
 
-    fn get_source_name(&self) -> String {
-        self.base.get_source_name()
-    }
+	fn get_source_name(&self) -> String {
+		self.base.get_source_name()
+	}
 
-    fn get_token_factory(&self) -> &dyn TokenFactory {
-        self.base.get_token_factory()
-    }
+	fn get_token_factory(&self) -> &dyn TokenFactory {
+		self.base.get_token_factory()
+	}
 }
 
 
@@ -178,7 +178,7 @@ lazy_static! {
 
 
 const _serializedATN: &'static str =
-    "\x03\u{608b}\u{a72a}\u{8133}\u{b9ed}\u{417c}\u{3be7}\u{7786}\u{5964}\x02\
+	"\x03\u{608b}\u{a72a}\u{8133}\u{b9ed}\u{417c}\u{3be7}\u{7786}\u{5964}\x02\
 		\x08\x2c\x08\x01\x04\x02\x09\x02\x04\x03\x09\x03\x04\x04\x09\x04\x04\x05\
 		\x09\x05\x04\x06\x09\x06\x04\x07\x09\x07\x03\x02\x03\x02\x03\x03\x03\x03\
 		\x03\x04\x03\x04\x03\x05\x06\x05\x17\x0a\x05\x0d\x05\x0e\x05\x18\x03\x05\