work

src/ir/mod.rs

@@ -1,11 +1,20 @@
-use std::collections::HashMap;
+use std::{
+    collections::HashMap,
+    ops::{Deref, DerefMut},
+};
 
-use crate::parser::{Body, Expr, Function, Ident, Literal, ParserError, Statement, Unresolved};
+use crate::parser::{
+    Body, Expr, FileSpan, Function, Ident, Literal, Module, ParserError, ParserErrors, Statement,
+};
 
 #[derive(Debug)]
 pub enum IRInstruction {
-    Li(IRIdent, Literal),
-    Mv(IRIdent, IRIdent),
+    Li(Var, Literal),
+    Mv(Var, Var),
+    Not(Var, Var),
+    Noti(Var, Literal),
+    La(Var, IRIdent),
+    Call(FnIdent, Vec<Var>),
 }
 
 #[derive(Debug)]
@@ -13,116 +22,257 @@ pub struct IRFunction {
     instructions: Vec<IRInstruction>,
 }
 
-impl Function<Unresolved> {
-    pub fn lower(&self, functions: &mut Vec<IRFunction>, map: &mut Namespace) -> Result<(), ParserError> {
-        let Ok(name) = &self.name.inner else {
-            return Ok(());
-        };
-        if map.get(name).is_some() {
-            Err(ParserError {
-                msg: format!("Already something named '{:?}'", self.name),
-                spans: vec![self.name.span],
-            })
-        } else {
-            map.add(name);
-            let mut instructions = Vec::new();
-            self.body.as_ref().map(|b| b.lower(map, &mut instructions));
-            functions.push(IRFunction { instructions });
-            Ok(())
+impl Module {
+    pub fn lower(&self, map: &mut Namespace, errors: &mut ParserErrors) {
+        for f in &self.functions {
+            if let Some(f) = f.as_ref() {
+                f.lower(map, errors);
+            }
         }
     }
 }
 
-impl Body<Unresolved> {
-    pub fn lower(&self, map: &Namespace, instructions: &mut Vec<IRInstruction>) {
-        let mut map = map.clone();
+impl Function {
+    pub fn lower(&self, map: &mut Namespace, errors: &mut ParserErrors) {
+        let Some(name) = self.name.as_ref() else {
+            return;
+        };
+        if map.get(name).is_some() {
+            errors.add(ParserError {
+                msg: format!("Already something named '{:?}'", self.name),
+                spans: vec![self.name.span],
+            });
+        } else {
+            let f = map.reserve_fn(self.name.span);
+            let mut instructions = Vec::new();
+            if let Some(b) = self.body.as_ref() {
+                b.lower(map, &mut instructions, errors)
+            }
+            map.write_fn(name, f, IRFunction { instructions });
+        }
+    }
+}
+
+impl Body {
+    pub fn lower(
+        &self,
+        map: &mut Namespace,
+        instructions: &mut Vec<IRInstruction>,
+        errors: &mut ParserErrors,
+    ) {
+        let mut map = map.push();
         for statement in &self.statements {
-            let Ok(statement) = &statement.inner else {
+            let Some(statement) = statement.as_ref() else {
                 continue;
             };
             match statement {
-                Statement::Let(name, expr) => {
-                    let Ok(name) = &name.inner else {
+                Statement::Let(name_node, expr) => {
+                    let Some(name) = name_node.as_ref() else {
                         continue;
                     };
-                    let name = map.add(name);
-                    let Ok(expr) = &expr.inner else {
+                    let Some(expr) = expr.as_ref() else {
                         continue;
                     };
-                    if let Ok(Some(res)) = expr.lower(&map, instructions) {
+                    let res = expr.lower(&mut map, instructions, errors);
+                    let name = map.add_var(name, name_node.span);
+                    if let Some(res) = res {
                         instructions.push(match res {
                             ExprResult::Lit(l) => IRInstruction::Li(name, l),
-                            ExprResult::Ident(i) => IRInstruction::Mv(name, i),
+                            ExprResult::Var(i) => IRInstruction::Mv(name, i),
+                            ExprResult::Fn(f) => todo!(),
                         });
                     }
                 }
                 Statement::Return(e) => todo!(),
-                Statement::Expr(expr) => todo!(),
+                Statement::Expr(expr) => {
+                    expr.as_ref().map(|e| e.lower(&mut map, instructions, errors));
+                }
             }
         }
     }
 }
 
-impl Expr<Unresolved> {
+impl Expr {
     pub fn lower(
         &self,
-        map: &Namespace,
+        map: &mut Namespace,
         instructions: &mut Vec<IRInstruction>,
-    ) -> Result<Option<ExprResult>, String> {
-        Ok(match self {
-            Expr::Lit(l) => {
-                let Ok(l) = &l.inner else {return Ok(None)};
-                Some(ExprResult::Lit(l.clone()))
-            },
+        errors: &mut ParserErrors,
+    ) -> Option<ExprResult> {
+        match self {
+            Expr::Lit(l) => Some(ExprResult::Lit(l.as_ref()?.clone())),
             Expr::Ident(i) => {
-                let Ok(i) = &i.inner else {return Ok(None)};
-                let Some(id) = map.get(i) else {
-                    return Err(format!("Identifier '{:?}' not found", i));
+                let Some(id) = map.get(i.as_ref()?) else {
+                    errors.add(ParserError::identifier_not_found(i));
+                    return None;
                 };
-                Some(ExprResult::Ident(id))
+                match id.ty() {
+                    IdentTypeMatch::Var(var) => Some(ExprResult::Var(var)),
+                    IdentTypeMatch::Fn(f) => Some(ExprResult::Fn(f)),
+                }
             }
             Expr::BinaryOp(_, _, _) => todo!(),
-            Expr::UnaryOp(_, _) => todo!(),
+            Expr::UnaryOp(op, e) => {
+                let res = e.as_ref()?.lower(&mut map, instructions, errors)?;
+                let res = match op {
+                    crate::parser::UnaryOperator::Not => {
+                        let temp = map.reserve_var(e.span);
+                        match res {
+                            ExprResult::Lit(l) => instructions.push(IRInstruction::Noti(temp, l)),
+                            ExprResult::Var(i) => instructions.push(IRInstruction::Not(temp, i)),
+                            ExprResult::Fn(_) => {
+                                errors.add(ParserError::from_span(
+                                    e.span,
+                                    "Cannot call not on a function".to_string(),
+                                ));
+                                return None;
+                            }
+                        }
+                        temp
+                    }
+                    crate::parser::UnaryOperator::Ref => todo!(),
+                };
+                Some(ExprResult::Var(res))
+            }
             Expr::Block(_) => todo!(),
-            Expr::Call(_, _) => todo!(),
-            Expr::Group(_) => todo!(),
-        })
+            Expr::Call(e, args) => {
+                let e = e.as_ref()?.lower(&mut map, instructions, errors);
+                let args = args.iter().map(|a| a.as_ref()?.lower(map, instructions, errors)).collect();
+                if let Some(r) = e {
+                    let fun = match r {
+                        ExprResult::Lit(literal) => todo!(),
+                        ExprResult::Var(var) => todo!(),
+                        ExprResult::Fn(f) => {
+                            instructions.push(IRInstruction::Call(f, args));
+                        },
+                    };
+                } else {
+                    todo!();
+                }
+            },
+            Expr::Group(e) => e.as_ref()?.lower(&mut map, instructions, errors),
+        }
     }
 }
 
-enum ExprResult {
+pub enum ExprResult {
     Lit(Literal),
-    Ident(IRIdent),
+    Var(Var),
+    Fn(FnIdent),
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub struct Namespace {
-    pub cur: usize,
-    pub map: HashMap<String, IRIdent>,
+    pub fns: Vec<Option<IRFunction>>,
+    pub vars: usize,
+    pub stack: Vec<HashMap<String, IRIdent>>,
 }
 
 impl Namespace {
     pub fn new() -> Self {
         Self {
-            cur: 0,
-            map: HashMap::new(),
+            fns: Vec::new(),
+            vars: 0,
+            stack: vec![HashMap::new()],
         }
     }
+    pub fn push(&mut self) -> NamespaceGuard {
+        self.stack.push(HashMap::new());
+        NamespaceGuard(self)
+    }
     pub fn get(&self, name: &Ident) -> Option<IRIdent> {
-        self.map.get(name.val()).copied()
+        for map in self.stack.iter().rev() {
+            let res = map.get(name.val());
+            if res.is_some() {
+                return res.copied();
             }
-    pub fn reserve(&mut self) -> IRIdent {
-        let id = IRIdent ( self.cur );
-        self.cur += 1;
+        }
+        None
+    }
+    pub fn reserve_var(&mut self, origin: FileSpan) -> Var {
+        let i = self.vars;
+        self.vars += 1;
+        Var(IRIdent {
+            origin,
+            ty: IdentType::Var,
+            i,
+        })
+    }
+    pub fn reserve_fn(&mut self, origin: FileSpan) -> FnIdent {
+        let i = self.fns.len();
+        self.fns.push(None);
+        FnIdent(IRIdent {
+            origin,
+            ty: IdentType::Fn,
+            i,
+        })
+    }
+    pub fn write_fn(&mut self, name: &Ident, id: FnIdent, f: IRFunction) -> IRIdent {
+        self.insert(name, id.0);
+        self.fns[id.0.i] = Some(f);
+        id.0
+    }
+    pub fn add_var(&mut self, name: &Ident, origin: FileSpan) -> Var {
+        let id = self.reserve_var(origin);
+        self.insert(name, id.0);
         id
     }
-    pub fn add(&mut self, name: &Ident) -> IRIdent {
-        let id = self.reserve();
-        self.map.insert(name.val().to_string(), id);
-        id
+    fn insert(&mut self, name: &Ident, id: IRIdent) {
+        let last = self.stack.len() - 1;
+        self.stack[last].insert(name.val().to_string(), id);
+    }
+}
+
+pub struct NamespaceGuard<'a>(&'a mut Namespace);
+
+impl Drop for NamespaceGuard<'_> {
+    fn drop(&mut self) {
+        self.0.stack.pop();
+    }
+}
+
+impl Deref for NamespaceGuard<'_> {
+    type Target = Namespace;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for NamespaceGuard<'_> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
     }
 }
 
 #[derive(Debug, Clone, Copy)]
-pub struct IRIdent (usize);
+pub struct IRIdent {
+    origin: FileSpan,
+    ty: IdentType,
+    i: usize,
+}
 
+#[derive(Debug, Clone, Copy)]
+pub struct FnIdent(IRIdent);
+#[derive(Debug, Clone, Copy)]
+pub struct Var(IRIdent);
+
+#[derive(Debug, Clone, Copy)]
+pub enum IdentType {
+    Var,
+    Fn,
+}
+
+#[derive(Debug, Clone, Copy)]
+pub enum IdentTypeMatch {
+    Var(Var),
+    Fn(FnIdent),
+}
+
+impl IRIdent {
+    pub fn ty(self) -> IdentTypeMatch {
+        match self.ty {
+            IdentType::Var => IdentTypeMatch::Var(Var(self)),
+            IdentType::Fn => IdentTypeMatch::Fn(FnIdent(self)),
+        }
+    }
+}

src/main.rs

@@ -7,6 +7,13 @@ mod ir;
 mod parser;
 
 fn main() {
-    parser::main();
+    let arg = std::env::args_os().nth(1);
+    if let Some(path) = arg {
+        let file = std::fs::read_to_string(path).expect("failed to read file");
+        println!("{file}");
+        parser::parse_file(&file);
+    } else {
+        parser::run_stdin();
+    }
     // compiler::main();
 }

src/parser/mod.rs

@@ -1,16 +1,5 @@
 mod v1;
 mod v2;
+mod v3;
 
-pub use v1::*;
-
-pub fn main() {
-    let arg = std::env::args_os().nth(1);
-    if let Some(path) = arg {
-        let file = std::fs::read_to_string(path).expect("failed to read file");
-        println!("{file}");
-        v1::parse_file(&file);
-        // v2::parse_file(&file);
-    } else {
-        v1::run_stdin();
-    }
-}
+pub use v3::*;

src/parser/v3/cursor.rs

@@ -0,0 +1,91 @@
+use super::error::ParserError;
+use super::token::{CharCursor, Keyword, Symbol, Token, TokenInstance};
+use super::FilePos;
+
+pub struct TokenCursor<'a> {
+    cursor: CharCursor<'a>,
+    next: Option<TokenInstance>,
+    next_pos: FilePos,
+    prev_end: FilePos,
+}
+
+impl<'a> TokenCursor<'a> {
+    pub fn next(&mut self) -> Option<TokenInstance> {
+        self.prev_end = self.cursor.prev_pos();
+        self.next_pos = self.cursor.next_pos();
+        std::mem::replace(&mut self.next, TokenInstance::parse(&mut self.cursor))
+    }
+    pub fn expect_next(&mut self) -> Result<TokenInstance, ParserError> {
+        self.peek().ok_or(ParserError::unexpected_end())?;
+        Ok(self.next().unwrap())
+    }
+    pub fn expect_token(&mut self, t: Token) -> Result<(), ParserError> {
+        let next = self.expect_next()?;
+        if t == next.token {
+            Ok(())
+        } else {
+            Err(ParserError::unexpected_token(&next, &format!("{t:?}")))
+        }
+    }
+    pub fn expect_sym(&mut self, symbol: Symbol) -> Result<(), ParserError> {
+        self.expect_token(Token::Symbol(symbol))
+    }
+    pub fn seek_sym(&mut self, symbol: Symbol) {
+        while self
+            .next()
+            .is_some_and(|n| n.token != Token::Symbol(symbol))
+        {}
+    }
+    pub fn seek_syms(&mut self, syms: &[Symbol]) {
+        while self
+            .peek()
+            .is_some_and(|n| !syms.iter().any(|s| n.is_symbol(*s)))
+        {
+            self.next();
+        }
+    }
+    pub fn seek(&mut self, f: impl Fn(&TokenInstance) -> bool) -> Option<&TokenInstance> {
+        loop {
+            if f(self.peek()?) {
+                return self.peek();
+            }
+            self.next();
+        }
+    }
+    pub fn expect_kw(&mut self, kw: Keyword) -> Result<(), ParserError> {
+        self.expect_token(Token::Keyword(kw))
+    }
+    pub fn peek(&self) -> Option<&TokenInstance> {
+        self.next.as_ref()
+    }
+    pub fn expect_peek(&mut self) -> Result<&TokenInstance, ParserError> {
+        self.peek().ok_or(ParserError::unexpected_end())
+    }
+    pub fn chars(&mut self) -> &mut CharCursor<'a> {
+        &mut self.cursor
+    }
+    pub fn prev_end(&self) -> FilePos {
+        self.prev_end
+    }
+    pub fn next_pos(&self) -> FilePos {
+        self.next_pos
+    }
+}
+
+impl<'a> From<&'a str> for TokenCursor<'a> {
+    fn from(string: &'a str) -> Self {
+        Self::from(CharCursor::from(string))
+    }
+}
+
+impl<'a> From<CharCursor<'a>> for TokenCursor<'a> {
+    fn from(mut cursor: CharCursor<'a>) -> Self {
+        let cur = TokenInstance::parse(&mut cursor);
+        Self {
+            cursor,
+            next: cur,
+            next_pos: FilePos::start(),
+            prev_end: FilePos::start(),
+        }
+    }
+}

src/parser/v3/error.rs

@@ -0,0 +1,74 @@
+use super::{
+    token::{FileSpan, TokenInstance},
+    FilePos, Ident, Node,
+};
+
+#[derive(Debug, Clone)]
+pub struct ParserError {
+    pub msg: String,
+    pub spans: Vec<FileSpan>,
+}
+
+pub struct ParserErrors {
+    pub errs: Vec<ParserError>,
+}
+
+impl ParserError {
+    pub fn from_instances(instances: &[&TokenInstance], msg: String) -> Self {
+        ParserError {
+            msg,
+            spans: instances.iter().map(|i| i.span).collect(),
+        }
+    }
+    pub fn from_msg(msg: String) -> Self {
+        Self {
+            msg,
+            spans: Vec::new(),
+        }
+    }
+    pub fn from_span(span: FileSpan, msg: String) -> Self {
+        Self {
+            msg,
+            spans: vec![span],
+        }
+    }
+    pub fn identifier_not_found(id: &Node<Ident>) -> Self {
+        Self {
+            msg: format!("Identifier '{}' not found", id.as_ref().unwrap().val()),
+            spans: vec![id.span],
+        }
+    }
+    pub fn at(pos: FilePos, msg: String) -> Self {
+        Self {
+            msg,
+            spans: vec![FileSpan::at(pos)],
+        }
+    }
+    pub fn unexpected_end() -> Self {
+        Self::from_msg("unexpected end of input".to_string())
+    }
+    pub fn unexpected_token(inst: &TokenInstance, expected: &str) -> Self {
+        let t = &inst.token;
+        ParserError::from_instances(
+            &[inst],
+            format!("unexpected token {t:?}; expected {expected}"),
+        )
+    }
+    pub fn write_for(&self, writer: &mut impl std::io::Write, file: &str) -> std::io::Result<()> {
+        let after = if self.spans.is_empty() { "" } else { ":" };
+        writeln!(writer, "error: {}{}", self.msg, after)?;
+        for span in &self.spans {
+            span.write_for(writer, file)?;
+        }
+        Ok(())
+    }
+}
+
+impl ParserErrors {
+    pub fn new() -> Self {
+        Self { errs: Vec::new() }
+    }
+    pub fn add(&mut self, err: ParserError) {
+        self.errs.push(err);
+    }
+}

src/parser/v3/mod.rs

@@ -0,0 +1,51 @@
+use std::io::{stdout, BufRead, BufReader};
+
+mod cursor;
+mod error;
+mod node;
+mod nodes;
+mod parse;
+mod token;
+
+pub use cursor::*;
+pub use error::*;
+pub use node::*;
+pub use nodes::*;
+pub use parse::*;
+pub use token::*;
+
+use crate::ir::Namespace;
+
+pub fn parse_file(file: &str) {
+    let mut errors = ParserErrors::new();
+    let res = Module::parse_node(&mut TokenCursor::from(file), &mut errors);
+    println!("{:?}", res.node);
+    let out = &mut stdout();
+    if let Some(module) = res.node.as_ref() {
+        let mut namespace = Namespace::new();
+        module.lower(&mut namespace, &mut errors);
+        println!("{:?}", namespace);
+    }
+    for err in errors.errs {
+        err.write_for(out, file).unwrap();
+    }
+}
+
+pub fn run_stdin() {
+    for line in BufReader::new(std::io::stdin()).lines() {
+        let mut errors = ParserErrors::new();
+        let str = &line.expect("failed to read line");
+        let mut cursor = TokenCursor::from(&str[..]);
+        if let Some(expr) = Statement::parse_node(&mut cursor, &mut errors).node.as_ref() {
+            if cursor.next().is_none() {
+                println!("{:?}", expr);
+            } else {
+                println!("uhhhh ehehe");
+            }
+        }
+        let out = &mut stdout();
+        for err in errors.errs {
+            err.write_for(out, str).unwrap();
+        }
+    }
+}

src/parser/v3/node.rs

@@ -0,0 +1,49 @@
+use std::{
+    fmt::Debug,
+    ops::{Deref, DerefMut},
+};
+
+use super::FileSpan;
+
+pub struct Node<T> {
+    pub inner: Option<T>,
+    pub span: FileSpan,
+}
+
+impl<T> Node<T> {
+    pub fn new(inner: T, span: FileSpan) -> Self {
+        Self {
+            inner: Some(inner),
+            span,
+        }
+    }
+    pub fn bx(self) -> Node<Box<T>> {
+        Node {
+            inner: self.inner.map(|v| Box::new(v)),
+            span: self.span,
+        }
+    }
+}
+
+impl<T> Deref for Node<T> {
+    type Target = Option<T>;
+    fn deref(&self) -> &Self::Target {
+        &self.inner
+    }
+}
+
+impl<T> DerefMut for Node<T> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.inner
+    }
+}
+
+impl<T: Debug> Debug for Node<T> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match &self.inner {
+            Some(v) => v.fmt(f),
+            None => f.write_str("{error}"),
+        }
+    }
+}
+

src/parser/v3/nodes/body.rs

@@ -0,0 +1,73 @@
+use std::fmt::{Debug, Write};
+
+use super::{
+    token::Symbol, Node, NodeParsable, Parsable, ParseResult, ParserError,
+    ParserErrors, Statement, TokenCursor,
+};
+use crate::util::Padder;
+
+pub struct Body {
+    pub statements: Vec<Node<Statement>>,
+}
+
+impl Parsable for Body {
+    fn parse(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> ParseResult<Self> {
+        let mut statements = Vec::new();
+        cursor.expect_sym(Symbol::OpenCurly)?;
+        if cursor.expect_peek()?.is_symbol(Symbol::CloseCurly) {
+            cursor.next();
+            return ParseResult::Ok(Self { statements });
+        }
+        let mut expect_semi = false;
+        let mut recover = false;
+        loop {
+            let Some(next) = cursor.peek() else {
+                recover = true;
+                errors.add(ParserError::unexpected_end());
+                break;
+            };
+            if next.is_symbol(Symbol::CloseCurly) {
+                cursor.next();
+                break;
+            }
+            if next.is_symbol(Symbol::Semicolon) {
+                cursor.next();
+                expect_semi = false;
+                continue;
+            } else if expect_semi {
+                errors.add(ParserError {
+                    msg: "expected ';'".to_string(),
+                    spans: vec![cursor.next_pos().char_span()],
+                });
+            }
+            let res = Statement::parse_node(cursor, errors);
+            statements.push(res.node);
+            expect_semi = true;
+            if res.recover {
+                cursor.seek_syms(&[Symbol::Semicolon, Symbol::CloseCurly]);
+                if cursor.peek().is_none() {
+                    recover = true;
+                    break;
+                }
+            }
+        }
+        ParseResult::from_recover(Self { statements }, recover)
+    }
+}
+
+impl Debug for Body {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        if self.statements.first().is_some() {
+            f.write_str("{\n    ")?;
+            let mut padder = Padder::new(f);
+            for s in &self.statements {
+                // they don't expose wrap_buf :grief:
+                padder.write_str(&format!("{s:?}\n"))?;
+            }
+            f.write_char('}')?;
+        } else {
+            f.write_str("{}")?;
+        }
+        Ok(())
+    }
+}

src/parser/v3/nodes/expr.rs

@@ -0,0 +1,156 @@
+use std::fmt::{Debug, Write};
+
+use super::{
+    BinaryOperator, Body, Ident, Literal, Node, NodeParsable, Parsable, ParseResult, ParserError,
+    ParserErrors, Symbol, TokenCursor, UnaryOperator,
+};
+
+type BoxNode = Node<Box<Expr>>;
+
+pub enum Expr {
+    Lit(Node<Literal>),
+    Ident(Node<Ident>),
+    BinaryOp(BinaryOperator, BoxNode, BoxNode),
+    UnaryOp(UnaryOperator, BoxNode),
+    Block(Node<Body>),
+    Call(BoxNode, Vec<Node<Expr>>),
+    Group(BoxNode),
+}
+
+impl Parsable for Expr {
+    fn parse(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> ParseResult<Self> {
+        let start = cursor.next_pos();
+        let next = cursor.expect_peek()?;
+        let mut e1 = if next.is_symbol(Symbol::OpenParen) {
+            cursor.next();
+            if cursor.expect_peek()?.is_symbol(Symbol::CloseParen) {
+                cursor.next();
+                return ParseResult::Ok(Expr::Lit(Node::new(
+                    Literal::Unit,
+                    cursor.next_pos().char_span(),
+                )));
+            }
+            let res = Node::parse(cursor, errors);
+            if res.recover {
+                cursor.seek_sym(Symbol::CloseParen);
+            }
+            cursor.expect_sym(Symbol::CloseParen)?;
+            Self::Group(res.node.bx())
+        } else if next.is_symbol(Symbol::OpenCurly) {
+            Self::Block(Body::parse_node(cursor, errors)?)
+        } else if let Some(op) = UnaryOperator::from_token(next) {
+            cursor.next();
+            return Node::parse(cursor, errors).map(|n| {
+                let n = n.bx();
+                if let Some(box Self::BinaryOp(op2, n1, n2)) = n.inner {
+                    let span = start.to(n1.span.end);
+                    Self::BinaryOp(op2, Node::new(Self::UnaryOp(op, n1), span).bx(), n2)
+                } else {
+                    Self::UnaryOp(op, n)
+                }
+            });
+        } else if let Some(val) = Node::maybe_parse(cursor, errors) {
+            Self::Lit(val)
+        } else {
+            let res = Node::parse(cursor, &mut ParserErrors::new());
+            if res.node.is_some() {
+                Self::Ident(res.node)
+            } else {
+                let next = cursor.expect_peek()?;
+                return ParseResult::Err(ParserError::unexpected_token(next, "an expression"));
+            }
+        };
+        let Some(mut next) = cursor.peek() else {
+            return ParseResult::Ok(e1);
+        };
+        while next.is_symbol(Symbol::OpenParen) {
+            cursor.next();
+            let mut args = Vec::new();
+            loop {
+                let next = cursor.expect_peek()?;
+                if next.is_symbol(Symbol::CloseParen) {
+                    break;
+                }
+                let res = Node::<Expr>::parse(cursor, errors);
+                args.push(res.node);
+                if res.recover {
+                    cursor.seek_syms(&[Symbol::CloseParen, Symbol::Comma]);
+                }
+                let next = cursor.expect_peek()?;
+                if !next.is_symbol(Symbol::Comma) {
+                    break;
+                }
+                cursor.next();
+            }
+            cursor.expect_sym(Symbol::CloseParen)?;
+            let end = cursor.prev_end();
+            e1 = Self::Call(Node::new(Box::new(e1), start.to(end)), args);
+            let Some(next2) = cursor.peek() else {
+                return ParseResult::Ok(e1);
+            };
+            next = next2
+        }
+        let end = cursor.prev_end();
+        let mut recover = false;
+        let res = if let Some(mut op) = BinaryOperator::from_token(&next.token) {
+            cursor.next();
+            let mut n1 = Node::new(e1, start.to(end)).bx();
+            let res = Node::parse(cursor, errors);
+            let mut n2 = res.node.bx();
+            recover = res.recover;
+            if let Some(box Self::BinaryOp(op2, _, _)) = n2.as_ref() {
+                if op.presedence() > op2.presedence() {
+                    let Some(box Self::BinaryOp(op2, n21, n22)) = n2.inner else {
+                        unreachable!();
+                    };
+                    let end = n21.span.end;
+                    n1 = Node::new(Self::BinaryOp(op, n1, n21), start.to(end)).bx();
+                    op = op2;
+                    n2 = n22;
+                }
+            }
+            Self::BinaryOp(op, n1, n2)
+        } else {
+            e1
+        };
+        ParseResult::from_recover(res, recover)
+    }
+}
+
+impl Debug for Expr {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Expr::Lit(c) => c.fmt(f)?,
+            Expr::Ident(n) => n.fmt(f)?,
+            Expr::Block(b) => b.fmt(f)?,
+            Expr::BinaryOp(op, e1, e2) => {
+                write!(f, "({:?}", *e1)?;
+                if op.pad() {
+                    write!(f, " {} ", op.str())?;
+                } else {
+                    write!(f, "{}", op.str())?;
+                }
+                write!(f, "{:?})", *e2)?;
+            }
+            Expr::Call(n, args) => {
+                n.fmt(f)?;
+                f.write_char('(')?;
+                if let Some(a) = args.first() {
+                    a.fmt(f)?;
+                }
+                for arg in args.iter().skip(1) {
+                    f.write_str(", ")?;
+                    arg.fmt(f)?;
+                }
+                f.write_char(')')?;
+            }
+            Expr::UnaryOp(op, e) => {
+                write!(f, "(")?;
+                write!(f, "{}", op.str())?;
+                write!(f, "{:?})", *e)?;
+            }
+            Expr::Group(inner) => inner.fmt(f)?,
+        }
+        Ok(())
+    }
+}

src/parser/v3/nodes/func.rs

@@ -0,0 +1,28 @@
+use super::{Body, Ident, Keyword, Node, Parsable, ParseResult, ParserErrors, Symbol, TokenCursor};
+use std::fmt::Debug;
+
+pub struct Function {
+    pub name: Node<Ident>,
+    pub body: Node<Body>,
+}
+
+impl Parsable for Function {
+    fn parse(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> ParseResult<Self> {
+        cursor.expect_kw(Keyword::Fn)?;
+        let name = Node::parse(cursor, errors)?;
+        cursor.expect_sym(Symbol::OpenParen)?;
+        cursor.expect_sym(Symbol::CloseParen)?;
+        Node::parse(cursor, errors).map(|body| Self { name, body })
+    }
+}
+
+impl Debug for Function {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str("fn ")?;
+        self.name.fmt(f)?;
+        f.write_str("() ")?;
+        self.body.fmt(f)?;
+        Ok(())
+    }
+}
+

src/parser/v3/nodes/ident.rs

@@ -0,0 +1,29 @@
+use std::fmt::Debug;
+use super::{Parsable, ParseResult, ParserError, Token};
+
+pub struct Ident(String);
+
+impl Ident {
+    pub fn val(&self) -> &String {
+        &self.0
+    }
+}
+
+impl Parsable for Ident {
+    fn parse(cursor: &mut super::TokenCursor, errors: &mut super::ParserErrors) -> ParseResult<Self> {
+        let next = cursor.expect_peek()?;
+        let Token::Ident(name) = &next.token else {
+            return ParseResult::Err(ParserError::unexpected_token(next, "an identifier"));
+        };
+        let name = name.to_string();
+        cursor.next();
+        ParseResult::Ok(Self(name))
+    }
+}
+
+impl Debug for Ident {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+

src/parser/v3/nodes/lit.rs

@@ -0,0 +1,114 @@
+use super::{
+    CharCursor, MaybeParsable, ParserError, ParserErrors, Symbol, Token, TokenCursor,
+};
+use std::fmt::Debug;
+
+#[derive(Clone, PartialEq, Eq)]
+pub enum Literal {
+    String(String),
+    Char(char),
+    Number(Number),
+    Unit,
+}
+
+#[derive(Clone, PartialEq, Eq)]
+pub struct Number {
+    pub whole: String,
+    pub decimal: Option<String>,
+    pub ty: Option<String>,
+}
+
+impl MaybeParsable for Literal {
+    fn maybe_parse(
+        cursor: &mut TokenCursor,
+        _: &mut ParserErrors,
+    ) -> Result<Option<Self>, ParserError> {
+        let inst = cursor.expect_peek()?;
+        let mut res = match &inst.token {
+            Token::Symbol(Symbol::SingleQuote) => {
+                let chars = cursor.chars();
+                let c = chars.expect_next()?;
+                chars.expect('\'')?;
+                Self::Char(c)
+            }
+            Token::Symbol(Symbol::DoubleQuote) => Self::String(string_from(cursor.chars())?),
+            Token::Ident(text) => {
+                let first = text.chars().next().unwrap();
+                if first.is_ascii_digit() {
+                    Self::Number(Number {
+                        whole: text.to_string(),
+                        decimal: None,
+                        ty: None,
+                    })
+                } else {
+                    return Ok(None);
+                }
+            }
+            _ => return Ok(None),
+        };
+        cursor.next();
+        if let (Some(next), Self::Number(num)) = (cursor.peek(), &mut res) {
+            if next.token.is_symbol(Symbol::Dot) {
+                cursor.next();
+                if let Some(next) = cursor.peek() {
+                    if let Token::Ident(i) = &next.token {
+                        if i.chars().next().unwrap().is_ascii_digit() {
+                            num.decimal = Some(i.to_string());
+                            cursor.next();
+                        }
+                    }
+                }
+            }
+        }
+        Ok(Some(res))
+    }
+}
+pub fn string_from(cursor: &mut CharCursor) -> Result<String, ParserError> {
+    let mut str = String::new();
+    loop {
+        let c = cursor.expect_next()?;
+        if c == '"' {
+            return Ok(str);
+        }
+        str.push(match c {
+            '\\' => {
+                let next = cursor.expect_next()?;
+                match next {
+                    '"' => '"',
+                    '\'' => '\'',
+                    't' => '\t',
+                    'n' => '\n',
+                    '0' => '\0',
+                    _ => {
+                        todo!();
+                    }
+                }
+            }
+            _ => c,
+        })
+    }
+}
+
+impl Debug for Literal {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::String(str) => str.fmt(f),
+            Self::Char(c) => c.fmt(f),
+            Self::Number(n) => n.fmt(f),
+            Self::Unit => f.write_str("()"),
+        }
+    }
+}
+
+impl Debug for Number {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.whole)?;
+        if let Some(d) = &self.decimal {
+            write!(f, ".{}", d)?;
+        }
+        if let Some(ty) = &self.ty {
+            write!(f, "T{}", ty)?;
+        }
+        Ok(())
+    }
+}

src/parser/v3/nodes/mod.rs

@@ -0,0 +1,19 @@
+mod body;
+mod expr;
+mod func;
+mod module;
+mod op;
+mod statement;
+mod lit;
+mod ident;
+
+pub use body::*;
+pub use expr::*;
+pub use func::*;
+pub use module::*;
+pub use op::*;
+pub use statement::*;
+pub use lit::*;
+pub use ident::*;
+
+use super::*;

src/parser/v3/nodes/module.rs

@@ -0,0 +1,35 @@
+use super::{
+    Function, Keyword, Node, Parsable, ParseResult, ParserError, ParserErrors, TokenCursor,
+};
+use std::fmt::Debug;
+
+pub struct Module {
+    pub functions: Vec<Node<Function>>,
+}
+
+impl Parsable for Module {
+    fn parse(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> ParseResult<Self> {
+        let mut functions = Vec::new();
+        loop {
+            let Some(next) = cursor.peek() else {
+                return ParseResult::Ok(Self { functions });
+            };
+            if next.is_keyword(Keyword::Fn) {
+                let res = Node::parse(cursor, errors);
+                functions.push(res.node);
+                if res.recover {
+                    return ParseResult::Recover(Self { functions });
+                }
+            } else {
+                errors.add(ParserError::unexpected_token(next, "fn"));
+                cursor.next();
+            }
+        }
+    }
+}
+
+impl Debug for Module {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.functions.fmt(f)
+    }
+}

src/parser/v3/nodes/op.rs

@@ -0,0 +1,96 @@
+use super::{Symbol, Token};
+
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum BinaryOperator {
+    Add,
+    Sub,
+    Mul,
+    Div,
+    LessThan,
+    GreaterThan,
+    Access,
+    Assign,
+}
+
+impl BinaryOperator {
+    pub fn presedence(&self) -> u32 {
+        match self {
+            Self::Assign => 0,
+            Self::LessThan => 1,
+            Self::GreaterThan => 1,
+            Self::Add => 2,
+            Self::Sub => 3,
+            Self::Mul => 4,
+            Self::Div => 5,
+            Self::Access => 6,
+        }
+    }
+    pub fn str(&self) -> &str {
+        match self {
+            Self::Add => "+",
+            Self::Sub => "-",
+            Self::Mul => "*",
+            Self::Div => "/",
+            Self::LessThan => "<",
+            Self::GreaterThan => ">",
+            Self::Access => ".",
+            Self::Assign => "=",
+        }
+    }
+    pub fn from_token(token: &Token) -> Option<Self> {
+        let Token::Symbol(symbol) = token else {
+            return None;
+        };
+        Some(match symbol {
+            Symbol::OpenAngle => Self::LessThan,
+            Symbol::CloseAngle => Self::GreaterThan,
+            Symbol::Plus => Self::Add,
+            Symbol::Minus => Self::Sub,
+            Symbol::Asterisk => Self::Mul,
+            Symbol::Slash => Self::Div,
+            Symbol::Dot => Self::Access,
+            Symbol::Equals => Self::Assign,
+            _ => {
+                return None;
+            }
+        })
+    }
+    pub fn pad(&self) -> bool {
+        match self {
+            Self::Add => true,
+            Self::Sub => true,
+            Self::Mul => true,
+            Self::Div => true,
+            Self::LessThan => true,
+            Self::GreaterThan => true,
+            Self::Access => false,
+            Self::Assign => true,
+        }
+    }
+}
+
+pub enum UnaryOperator {
+    Not,
+    Ref,
+}
+
+impl UnaryOperator {
+    pub fn str(&self) -> &str {
+        match self {
+            Self::Not => "!",
+            Self::Ref => "&",
+        }
+    }
+    pub fn from_token(token: &Token) -> Option<Self> {
+        let Token::Symbol(symbol) = token else {
+            return None;
+        };
+        Some(match symbol {
+            Symbol::Ampersand => Self::Ref,
+            Symbol::Bang => Self::Not,
+            _ => {
+                return None;
+            }
+        })
+    }
+}

src/parser/v3/nodes/statement.rs

@@ -0,0 +1,53 @@
+use super::{
+    Expr, Ident, Keyword, Node, Parsable, ParseResult, ParserErrors, Symbol, Token, TokenCursor,
+};
+use std::fmt::{Debug, Write};
+
+pub enum Statement {
+    Let(Node<Ident>, Node<Expr>),
+    Return(Node<Expr>),
+    Expr(Node<Expr>),
+}
+
+impl Parsable for Statement {
+    fn parse(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> ParseResult<Self> {
+        let next = cursor.expect_peek()?;
+        match next.token {
+            Token::Keyword(Keyword::Let) => {
+                cursor.next();
+                let name = Node::parse(cursor, errors)?;
+                cursor.expect_sym(Symbol::Equals)?;
+                Node::parse(cursor, errors).map(|expr| Self::Let(name, expr))
+            }
+            Token::Keyword(Keyword::Return) => {
+                cursor.next();
+                Node::parse(cursor, errors).map(Self::Return)
+            }
+            _ => Node::parse(cursor, errors).map(Self::Expr),
+        }
+    }
+}
+
+impl Debug for Statement {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Statement::Let(n, e) => {
+                f.write_str("let ")?;
+                n.fmt(f);
+                f.write_str(" = ")?;
+                e.fmt(f)?;
+                f.write_char(';')?;
+            }
+            Statement::Return(e) => {
+                f.write_str("return ")?;
+                e.fmt(f)?;
+                f.write_char(';')?;
+            }
+            Statement::Expr(e) => {
+                e.fmt(f)?;
+                f.write_char(';')?;
+            }
+        }
+        Ok(())
+    }
+}

src/parser/v3/parse.rs

@@ -0,0 +1,178 @@
+use std::{
+    convert::Infallible,
+    ops::{ControlFlow, FromResidual, Try},
+};
+
+use super::{Node, ParserError, ParserErrors, TokenCursor};
+
+pub enum ParseResult<T> {
+    Ok(T),
+    Recover(T),
+    Err(ParserError),
+    SubErr,
+}
+
+impl<T> ParseResult<T> {
+    pub fn from_recover(data: T, recover: bool) -> Self {
+        if recover {
+            Self::Recover(data)
+        } else {
+            Self::Ok(data)
+        }
+    }
+}
+
+impl<T> Try for ParseResult<T> {
+    type Output = Result<T, T>;
+    type Residual = Option<ParserError>;
+    fn from_output(output: Self::Output) -> Self {
+        match output {
+            Ok(v) => Self::Ok(v),
+            Err(v) => Self::Recover(v),
+        }
+    }
+    fn branch(self) -> ControlFlow<Self::Residual, Self::Output> {
+        match self {
+            ParseResult::Ok(v) => ControlFlow::Continue(Ok(v)),
+            ParseResult::Recover(v) => ControlFlow::Continue(Err(v)),
+            ParseResult::Err(e) => ControlFlow::Break(Some(e)),
+            ParseResult::SubErr => ControlFlow::Break(None),
+        }
+    }
+}
+
+impl<T> FromResidual for ParseResult<T> {
+    fn from_residual(residual: <Self as Try>::Residual) -> Self {
+        match residual {
+            Some(err) => Self::Err(err),
+            None => Self::SubErr,
+        }
+    }
+}
+
+impl<T> FromResidual<Result<Infallible, ParserError>> for ParseResult<T> {
+    fn from_residual(residual: Result<Infallible, ParserError>) -> Self {
+        match residual {
+            Err(e) => Self::Err(e),
+        }
+    }
+}
+
+impl<T, U> FromResidual<ParseResult<T>> for ParseResult<U> {
+    fn from_residual(residual: ParseResult<T>) -> Self {
+        match residual {
+            ParseResult::Err(e) => Self::Err(e),
+            ParseResult::SubErr => Self::SubErr,
+            _ => unreachable!(),
+        }
+    }
+}
+
+pub struct NodeParseResult<T> {
+    pub node: Node<T>,
+    pub recover: bool,
+}
+
+impl<T> NodeParseResult<T> {
+    pub fn map<F: FnOnce(Node<T>) -> U, U>(self, op: F) -> ParseResult<U> {
+        let res = op(self.node);
+        if self.recover {
+            ParseResult::Recover(res)
+        } else {
+            ParseResult::Ok(res)
+        }
+    }
+}
+
+impl<T> Try for NodeParseResult<T> {
+    type Output = Node<T>;
+    type Residual = ParseResult<T>;
+
+    fn from_output(output: Self::Output) -> Self {
+        Self {
+            node: output,
+            recover: false,
+        }
+    }
+
+    fn branch(self) -> ControlFlow<Self::Residual, Self::Output> {
+        if self.recover {
+            ControlFlow::Break(ParseResult::SubErr)
+        } else {
+            ControlFlow::Continue(self.node)
+        }
+    }
+}
+
+impl<T> FromResidual for NodeParseResult<T> {
+    fn from_residual(_: <Self as Try>::Residual) -> Self {
+        // I hope this is unreachable ???
+        unreachable!()
+    }
+}
+
+pub trait Parsable: Sized {
+    fn parse(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> ParseResult<Self>;
+}
+
+pub trait MaybeParsable: Sized {
+    fn maybe_parse(
+        cursor: &mut TokenCursor,
+        errors: &mut ParserErrors,
+    ) -> Result<Option<Self>, ParserError>;
+}
+
+impl<T: Parsable> Node<T> {
+    pub fn parse(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> NodeParseResult<T> {
+        let start = cursor.next_pos();
+        let (inner, recover) = match T::parse(cursor, errors) {
+            ParseResult::Ok(v) => (Some(v), false),
+            ParseResult::Recover(v) => (Some(v), true),
+            ParseResult::Err(e) => {
+                errors.add(e);
+                (None, true)
+            }
+            ParseResult::SubErr => (None, true),
+        };
+        let end = cursor.prev_end();
+        NodeParseResult {
+            node: Self {
+                inner,
+                span: start.to(end),
+            },
+            recover,
+        }
+    }
+}
+
+impl<T: MaybeParsable> Node<T> {
+    pub fn maybe_parse(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> Option<Self> {
+        let start = cursor.next_pos();
+        let inner = match T::maybe_parse(cursor, errors) {
+            Ok(v) => Some(v?),
+            Err(e) => {
+                errors.add(e);
+                None
+            }
+        };
+        let end = cursor.prev_end();
+        Some(Self {
+            inner,
+            span: start.to(end),
+        })
+    }
+}
+
+pub trait NodeParsable {
+    fn parse_node(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> NodeParseResult<Self>
+    where
+        Self: Sized;
+}
+impl<T: Parsable> NodeParsable for T {
+    fn parse_node(cursor: &mut TokenCursor, errors: &mut ParserErrors) -> NodeParseResult<Self>
+    where
+        Self: Sized,
+    {
+        Node::<Self>::parse(cursor, errors)
+    }
+}

src/parser/v3/token/cursor.rs

@@ -0,0 +1,68 @@
+use std::{iter::Peekable, str::Chars};
+
+use super::super::ParserError;
+use super::FilePos;
+
+pub struct CharCursor<'a> {
+    chars: Peekable<Chars<'a>>,
+    next_pos: FilePos,
+    prev_pos: FilePos,
+}
+
+impl CharCursor<'_> {
+    pub fn next(&mut self) -> Option<char> {
+        let res = self.peek()?;
+        self.advance();
+        Some(res)
+    }
+    pub fn expect(&mut self, c: char) -> Result<(), ParserError> {
+        let next = self.expect_next()?;
+        if next == c {
+            Ok(())
+        } else {
+            Err(ParserError::at(
+                self.prev_pos,
+                format!("unexpected char '{next}'; expected '{c}'"),
+            ))
+        }
+    }
+    pub fn skip_whitespace(&mut self) {
+        while self.peek().is_some_and(|c| c.is_whitespace()) {
+            self.advance();
+        }
+    }
+    pub fn peek(&mut self) -> Option<char> {
+        self.chars.peek().copied()
+    }
+    pub fn advance(&mut self) {
+        let Some(next) = self.chars.next() else {
+            return;
+        };
+        self.prev_pos = self.next_pos;
+        if next == '\n' {
+            self.next_pos.col = 0;
+            self.next_pos.line += 1;
+        } else {
+            self.next_pos.col += 1;
+        }
+    }
+    pub fn expect_next(&mut self) -> Result<char, ParserError> {
+        self.next().ok_or(ParserError::unexpected_end())
+    }
+    pub fn next_pos(&self) -> FilePos {
+        self.next_pos
+    }
+    pub fn prev_pos(&self) -> FilePos {
+        self.prev_pos
+    }
+}
+
+impl<'a> From<&'a str> for CharCursor<'a> {
+    fn from(value: &'a str) -> Self {
+        Self {
+            chars: value.chars().peekable(),
+            next_pos: FilePos::start(),
+            prev_pos: FilePos::start(),
+        }
+    }
+}

src/parser/v3/token/file.rs

@@ -0,0 +1,80 @@
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct FilePos {
+    pub line: usize,
+    pub col: usize,
+}
+
+#[derive(Debug, Clone, Copy)]
+pub struct FileSpan {
+    pub start: FilePos,
+    pub end: FilePos,
+}
+
+impl FilePos {
+    pub fn start() -> Self {
+        Self { line: 0, col: 0 }
+    }
+}
+
+impl FilePos {
+    pub fn to(self, end: FilePos) -> FileSpan {
+        FileSpan { start: self, end }
+    }
+    pub fn char_span(self) -> FileSpan {
+        FileSpan::at(self)
+    }
+}
+
+const BEFORE: usize = 1;
+const AFTER: usize = 0;
+
+impl FileSpan {
+    pub fn at(pos: FilePos) -> Self {
+        Self {
+            start: pos,
+            end: pos,
+        }
+    }
+    pub fn write_for(&self, writer: &mut impl std::io::Write, file: &str) -> std::io::Result<()> {
+        let start = self.start.line.saturating_sub(BEFORE);
+        let num_before = self.start.line - start;
+        let mut lines = file.lines().skip(start);
+        let width = format!("{}", self.end.line + AFTER).len();
+        let same_line = self.start.line == self.end.line;
+        for i in 0..num_before {
+            writeln!(writer, "{:>width$} | {}", start + i, lines.next().unwrap())?;
+        }
+        let line = lines.next().unwrap();
+        writeln!(writer, "{:>width$} | {}", self.start.line, line)?;
+        let len = if same_line {
+            self.end.col - self.start.col + 1
+        } else {
+            line.len() - self.start.col
+        };
+        writeln!(
+            writer,
+            "{} | {}",
+            " ".repeat(width),
+            " ".repeat(self.start.col) + &"^".repeat(len)
+        )?;
+        if !same_line {
+            for _ in 0..self.end.line - self.start.line - 1 {
+                lines.next();
+            }
+            let line = lines.next().unwrap();
+            writeln!(writer, "{:>width$} | {}", self.end.line, line)?;
+            writeln!(
+                writer,
+                "{} | {}",
+                " ".repeat(width),
+                "^".repeat(self.end.col + 1)
+            )?;
+        }
+        // for i in 0..AFTER {
+        //     if let Some(next) = lines.next() {
+        //         writeln!(writer, "{:>width$} | {}", self.end.line + i + 1, next)?;
+        //     }
+        // }
+        Ok(())
+    }
+}

src/parser/v3/token/keyword.rs

@@ -0,0 +1,19 @@
+#[derive(Debug, PartialEq, Eq, Clone, Copy)]
+pub enum Keyword {
+    Fn,
+    Let,
+    If,
+    Return,
+}
+
+impl Keyword {
+    pub fn from_string(str: &str) -> Option<Self> {
+        Some(match str {
+            "fn" => Self::Fn,
+            "let" => Self::Let,
+            "if" => Self::If,
+            "return" => Self::Return,
+            _ => return None,
+        })
+    }
+}

src/parser/v3/token/mod.rs

@@ -0,0 +1,90 @@
+mod cursor;
+mod file;
+mod keyword;
+mod symbol;
+
+use std::ops::Deref;
+
+pub use cursor::*;
+pub use file::*;
+pub use keyword::*;
+pub use symbol::*;
+
+#[derive(Debug, PartialEq, Eq, Clone)]
+pub enum Token {
+    Symbol(Symbol),
+    Ident(String),
+    Keyword(Keyword),
+}
+
+#[derive(Debug, Clone)]
+pub struct TokenInstance {
+    pub token: Token,
+    pub span: FileSpan,
+}
+
+impl TokenInstance {
+    pub fn parse(cursor: &mut CharCursor) -> Option<TokenInstance> {
+        cursor.skip_whitespace();
+        cursor.peek()?;
+        let start = cursor.next_pos();
+        if let Some(s) = Symbol::parse(cursor) {
+            if s == Symbol::DoubleSlash {
+                while cursor.next() != Some('\n') {}
+                return Self::parse(cursor);
+            }
+            let end = cursor.prev_pos();
+            return Some(Self {
+                token: Token::Symbol(s),
+                span: FileSpan { start, end },
+            });
+        }
+        let mut word = String::new();
+        while let Some(c) = cursor.peek() {
+            if c.is_whitespace() || Symbol::from_char(c).is_some() {
+                break;
+            }
+            word.push(c);
+            cursor.advance();
+        }
+        let end = cursor.prev_pos();
+        let token = if let Some(keyword) = Keyword::from_string(&word) {
+            Token::Keyword(keyword)
+        } else {
+            Token::Ident(word)
+        };
+        Some(Self {
+            token,
+            span: FileSpan { start, end },
+        })
+    }
+}
+
+impl Token {
+    pub fn is_symbol(&self, symbol: Symbol) -> bool {
+        match self {
+            Token::Symbol(s) => *s == symbol,
+            _ => false,
+        }
+    }
+    pub fn is_symbol_and(&self, f: impl Fn(Symbol) -> bool) -> bool {
+        match self {
+            Token::Symbol(s) => f(*s),
+            _ => false,
+        }
+    }
+    pub fn is_keyword(&self, kw: Keyword) -> bool {
+        match self {
+            Token::Keyword(k) => *k == kw,
+            _ => false,
+        }
+    }
+}
+
+impl Deref for TokenInstance {
+    type Target = Token;
+
+    fn deref(&self) -> &Self::Target {
+        &self.token
+    }
+}

src/parser/v3/token/symbol.rs

@@ -0,0 +1,146 @@
+use std::fmt::Debug;
+
+use super::CharCursor;
+
+#[derive(PartialEq, Eq, Clone, Copy)]
+pub enum Symbol {
+    Semicolon,
+    Colon,
+    DoubleColon,
+    Equals,
+    DoubleEquals,
+    Arrow,
+    DoubleArrow,
+    Plus,
+    Minus,
+    Asterisk,
+    Slash,
+    DoubleSlash,
+    Dot,
+    OpenParen,
+    CloseParen,
+    OpenCurly,
+    CloseCurly,
+    OpenSquare,
+    CloseSquare,
+    OpenAngle,
+    CloseAngle,
+    SingleQuote,
+    DoubleQuote,
+    Bang,
+    Ampersand,
+    DoubleAmpersand,
+    Pipe,
+    DoublePipe,
+    Comma,
+}
+
+impl Symbol {
+    pub fn parse(cursor: &mut CharCursor) -> Option<Self> {
+        Self::from_char(cursor.peek()?).map(|mut s| {
+            cursor.advance();
+            s.finish(cursor);
+            s
+        })
+    }
+    pub fn from_char(c: char) -> Option<Self> {
+        Some(match c {
+            '(' => Self::OpenParen,
+            ')' => Self::CloseParen,
+            '[' => Self::OpenSquare,
+            ']' => Self::CloseSquare,
+            '{' => Self::OpenCurly,
+            '}' => Self::CloseCurly,
+            '<' => Self::OpenAngle,
+            '>' => Self::CloseAngle,
+            ';' => Self::Semicolon,
+            ':' => Self::Colon,
+            '+' => Self::Plus,
+            '-' => Self::Minus,
+            '*' => Self::Asterisk,
+            '/' => Self::Slash,
+            '=' => Self::Equals,
+            '.' => Self::Dot,
+            '\'' => Self::SingleQuote,
+            '"' => Self::DoubleQuote,
+            '!' => Self::Bang,
+            '&' => Self::Ampersand,
+            '|' => Self::Pipe,
+            ',' => Self::Comma,
+            _ => return None,
+        })
+    }
+    pub fn finish(&mut self, cursor: &mut CharCursor) {
+        let Some(next) = cursor.peek() else {
+            return;
+        };
+        *self = match self {
+            Self::Colon => match next {
+                ':' => Self::DoubleColon,
+                _ => return,
+            },
+            Self::Minus => match next {
+                '>' => Self::Arrow,
+                _ => return,
+            },
+            Self::Equals => match next {
+                '=' => Self::DoubleEquals,
+                '>' => Self::DoubleArrow,
+                _ => return,
+            },
+            Self::Slash => match next {
+                '/' => Self::DoubleSlash,
+                _ => return,
+            },
+            Self::Ampersand => match next {
+                '&' => Self::DoubleAmpersand,
+                _ => return,
+            },
+            Self::Pipe => match next {
+                '&' => Self::DoublePipe,
+                _ => return,
+            },
+            _ => return,
+        };
+        cursor.advance();
+    }
+    pub fn str(&self) -> &str {
+        match self {
+            Self::Semicolon => ";",
+            Self::Colon => ":",
+            Self::DoubleColon => "::",
+            Self::Equals => "=",
+            Self::DoubleEquals => "==",
+            Self::Arrow => "->",
+            Self::DoubleArrow => "=>",
+            Self::Plus => "+",
+            Self::Minus => "-",
+            Self::Asterisk => "*",
+            Self::Slash => "/",
+            Self::DoubleSlash => "//",
+            Self::Dot => ".",
+            Self::OpenParen => "(",
+            Self::CloseParen => ")",
+            Self::OpenCurly => "{",
+            Self::CloseCurly => "}",
+            Self::OpenSquare => "[",
+            Self::CloseSquare => "]",
+            Self::OpenAngle => "<",
+            Self::CloseAngle => ">",
+            Self::SingleQuote => "'",
+            Self::DoubleQuote => "\"",
+            Self::Bang => "!",
+            Self::Comma => ",",
+            Self::Ampersand => "&",
+            Self::DoubleAmpersand => "&&",
+            Self::Pipe => "|",
+            Self::DoublePipe => "||",
+        }
+    }
+}
+
+impl Debug for Symbol {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "'{}'", self.str())
+    }
+}