lang: start working on parser that parses to events

crates/lang/src/parser/ast/lossless/parser.rs

@@ -11,20 +11,37 @@ use crate::parser::{
 
 use super::lex::{self, SyntaxKind};
 
-mod parsers {
-    use rowan::GreenNode;
+pub mod parser_to_events {
+    use chumsky::Parser;
 
-    use crate::parser::ast::lossless::lex::SyntaxKind;
+    use crate::parser::ast::lossless::lex::SyntaxKind::{self, *};
 
-    use super::SyntaxError;
-
-    struct ParseResult {
-        green_node: GreenNode,
-        errors: Vec<SyntaxError>,
+    #[derive(Debug, PartialEq, Eq)]
+    pub(super) enum Event {
+        StartNode,
+        StartErr(SyntaxError),
+        EatToken,
+        FinishNode,
+        FinishErr,
     }
 
-    trait Parser {
-        fn parse<'src>(input: &[(SyntaxKind, &'src str)]) -> ParseResult;
+    #[derive(Debug, PartialEq, Eq)]
+    enum SyntaxError {
+        Expected(SyntaxKind),
+        AttrExpectedValue,
+        /// guessed if there's a newline and attr on next line without comma
+        /// should then suggest comma after attr
+        ExpectedCommaBetweenAttrs,
+    }
+
+    pub fn to_events(src: &str) -> Vec<Event> {
+        let mut tokens = lex::lex(src);
+        parser().parse(tokens)
+    }
+
+    pub fn parser() -> impl Parser<'static, SyntaxKind, Vec<Event>> {
+        let whitespace = just(WHITESPACE).or(NEWLINE).repeated().collect::<Vec<_>>();
+        whitespace
     }
 }