symbol resolution works 🎉🎉🎉

src/ast_lower.rs

@@ -0,0 +1,358 @@
+use std::{collections::HashMap, rc::Rc, sync::Mutex};
+
+use crate::{
+    ast::{self},
+    hir::{
+        Expr, ExprId, ExprKind, OwnerId, Pack, Param, ParamId, Stmt, StmtId, StmtKind, Typ, TypId,
+        TypKind,
+    },
+    pos::{Error, ErrorAcc, ErrorKind},
+};
+
+pub struct AstLower {
+    error_acc: Rc<Mutex<ErrorAcc>>,
+    stmts: Vec<Stmt>,
+    exprs: Vec<Expr>,
+    typs: Vec<Typ>,
+    params: Vec<Param>,
+    owners: HashMap<OwnerId, StmtId>,
+    next_owner_id: u64,
+    ribs: Vec<Rib>,
+    rib: RibId,
+}
+
+impl AstLower {
+    pub fn new(error_acc: Rc<Mutex<ErrorAcc>>) -> Self {
+        let ribs = vec![Rib::new_root()];
+        Self {
+            error_acc,
+            stmts: Vec::new(),
+            exprs: Vec::new(),
+            typs: Vec::new(),
+            params: Vec::new(),
+            owners: HashMap::new(),
+            next_owner_id: 0,
+            ribs,
+            rib: RibId(0),
+        }
+    }
+
+    pub fn lower_ast(&mut self, ast: &[ast::Stmt]) {
+        self.lower_stmts(ast);
+    }
+
+    pub fn pack_it_up(self) -> Pack {
+        Pack::new(self.stmts, self.exprs, self.typs, self.params, self.owners)
+    }
+
+    fn lower_stmts(&mut self, stmts: &[ast::Stmt]) {
+        self.find_fns(stmts);
+        for stmt in stmts {
+            self.lower_stmt(stmt);
+        }
+    }
+
+    fn find_fns(&mut self, stmts: &[ast::Stmt]) {
+        for stmt in stmts {
+            if let ast::StmtKind::Fn {
+                subject,
+                params: _,
+                return_typ: _,
+                body: _,
+            } = &stmt.kind
+            {
+                let ast::Expr {
+                    kind: ast::ExprKind::Ident(ident_id),
+                    pos: _,
+                } = subject.as_ref()
+                else {
+                    unreachable!();
+                };
+                let owner_id = self.next_owner_id();
+                self.ribs[self.rib.0]
+                    .define_item(*ident_id, owner_id)
+                    .unwrap()
+            }
+        }
+    }
+
+    fn lower_stmt(&mut self, stmt: &ast::Stmt) -> StmtId {
+        let ast::Stmt { kind, pos } = stmt;
+        match &kind {
+            ast::StmtKind::Error => self.intern_stmt(Stmt::new(StmtKind::Error, pos.clone())),
+            ast::StmtKind::Let { subject, value } => {
+                self.make_rib();
+                let owner_id = self.next_owner_id();
+                let subject = self.lower_param(subject, owner_id);
+                let value = self.lower_expr(value);
+                let stmt_id =
+                    self.intern_stmt(Stmt::new(StmtKind::Let { subject, value }, pos.clone()));
+                self.owners.insert(owner_id, stmt_id);
+                stmt_id
+            }
+            ast::StmtKind::Fn {
+                subject,
+                params,
+                return_typ,
+                body,
+            } => {
+                let ast::ExprKind::Ident(ident_id) = subject.kind else {
+                    unreachable!();
+                };
+                let owner_id = self.next_owner_id();
+                let params = params
+                    .iter()
+                    .map(|param| self.lower_param(param, owner_id))
+                    .collect::<Vec<_>>();
+                let return_typ = return_typ.as_ref().map(|typ| self.lower_typ(typ));
+                let body = self.lower_expr(body);
+                self.intern_stmt(Stmt::new(
+                    StmtKind::Fn {
+                        subject_ident_id: ident_id,
+                        params,
+                        return_typ,
+                        body,
+                    },
+                    pos.clone(),
+                ))
+            }
+            ast::StmtKind::Return { expr } => {
+                let expr = expr.as_ref().map(|expr| self.lower_expr(expr));
+                self.intern_stmt(Stmt::new(StmtKind::Return { expr }, pos.clone()))
+            }
+            ast::StmtKind::Break { expr } => {
+                let expr = expr.as_ref().map(|expr| self.lower_expr(expr));
+                self.intern_stmt(Stmt::new(StmtKind::Return { expr }, pos.clone()))
+            }
+            ast::StmtKind::Assign { subject, value } => {
+                let subject = self.lower_expr(subject);
+                let value = self.lower_expr(value);
+                self.intern_stmt(Stmt::new(StmtKind::Assign { subject, value }, pos.clone()))
+            }
+            ast::StmtKind::Expr(expr) => {
+                let expr = self.lower_expr(expr);
+                self.intern_stmt(Stmt::new(StmtKind::Expr(expr), pos.clone()))
+            }
+        }
+    }
+
+    fn lower_expr(&mut self, expr: &ast::Expr) -> ExprId {
+        let ast::Expr { kind, pos } = expr;
+        match kind {
+            ast::ExprKind::Error => self.intern_expr(Expr::new(ExprKind::Error, pos.clone())),
+            ast::ExprKind::Ident(ident_id) => {
+                let Some(owner) = self.rib().ident_owner(&self.ribs, *ident_id) else {
+                    println!("ribs: {:#?}", self.ribs);
+                    self.error_acc.lock().unwrap().add(Error {
+                        kind: ErrorKind::Checker,
+                        pos: Some(pos.clone()),
+                        msg: format!("undefined identifier '{ident_id}'"),
+                    });
+                    return self.intern_expr(Expr::new(ExprKind::Error, pos.clone()));
+                };
+                self.intern_expr(Expr::new(
+                    ExprKind::Ident {
+                        ident_id: *ident_id,
+                        owner,
+                    },
+                    pos.clone(),
+                ))
+            }
+            ast::ExprKind::Int(value) => {
+                self.intern_expr(Expr::new(ExprKind::Int(*value), pos.clone()))
+            }
+            ast::ExprKind::Str(value) => {
+                self.intern_expr(Expr::new(ExprKind::Str(value.clone()), pos.clone()))
+            }
+            ast::ExprKind::Group(expr) => self.lower_expr(expr),
+            ast::ExprKind::Block { stmts, expr } => {
+                let outer_rib = self.rib;
+                self.rib = self.make_rib();
+                let stmts = stmts
+                    .iter()
+                    .map(|stmt| self.lower_stmt(stmt))
+                    .collect::<Vec<_>>();
+                let expr = expr.as_ref().map(|expr| self.lower_expr(expr));
+                self.rib = outer_rib;
+                self.intern_expr(Expr::new(ExprKind::Block { stmts, expr }, pos.clone()))
+            }
+            ast::ExprKind::Call { subject, args } => {
+                let subject = self.lower_expr(subject);
+                let args = args
+                    .iter()
+                    .map(|arg| self.lower_expr(arg))
+                    .collect::<Vec<_>>();
+                self.intern_expr(Expr::new(ExprKind::Call { subject, args }, pos.clone()))
+            }
+            ast::ExprKind::If {
+                cond,
+                truthy,
+                falsy,
+            } => {
+                let cond = self.lower_expr(cond);
+                let truthy = self.lower_expr(truthy);
+                let falsy = falsy.as_ref().map(|expr| self.lower_expr(expr));
+                self.intern_expr(Expr::new(
+                    ExprKind::If {
+                        cond,
+                        truthy,
+                        falsy,
+                    },
+                    pos.clone(),
+                ))
+            }
+            ast::ExprKind::Loop { body } => {
+                let body = self.lower_expr(body);
+                self.intern_expr(Expr::new(ExprKind::Loop { body }, pos.clone()))
+            }
+        }
+    }
+
+    fn lower_typ(&mut self, typ: &ast::Typ) -> TypId {
+        let ast::Typ { kind, pos } = typ;
+        match kind {
+            ast::TypKind::Error => self.intern_typ(Typ::new(TypKind::Error, pos.clone())),
+            ast::TypKind::Ident(ident_id) => {
+                let Some(owner) = self.rib().ident_owner(&self.ribs, *ident_id) else {
+                    todo!();
+                };
+                self.intern_typ(Typ::new(
+                    TypKind::Ident {
+                        ident_id: *ident_id,
+                        owner,
+                    },
+                    pos.clone(),
+                ))
+            }
+        }
+    }
+
+    fn lower_param(&mut self, param: &ast::Param, owner_id: OwnerId) -> ParamId {
+        let ast::Param { subject, typ, pos } = param;
+        let ast::ExprKind::Ident(ident_id) = subject.kind else {
+            unreachable!();
+        };
+        let typ = typ.as_ref().map(|typ| self.lower_typ(typ.as_ref()));
+        let param_id = self.intern_param(Param {
+            subject_ident_id: ident_id,
+            typ,
+            pos: pos.clone(),
+        });
+        self.rib_mut().define_param(ident_id, owner_id, param_id);
+        param_id
+    }
+
+    fn intern_stmt(&mut self, stmt: Stmt) -> StmtId {
+        match self.stmts.iter().position(|v| *v == stmt) {
+            Some(id) => StmtId(id),
+            None => {
+                let id = self.stmts.len();
+                self.stmts.push(stmt);
+                StmtId(id)
+            }
+        }
+    }
+
+    fn intern_expr(&mut self, expr: Expr) -> ExprId {
+        match self.exprs.iter().position(|v| *v == expr) {
+            Some(id) => ExprId(id),
+            None => {
+                let id = self.exprs.len();
+                self.exprs.push(expr);
+                ExprId(id)
+            }
+        }
+    }
+
+    fn intern_typ(&mut self, typ: Typ) -> TypId {
+        match self.typs.iter().position(|v| *v == typ) {
+            Some(id) => TypId(id),
+            None => {
+                let id = self.typs.len();
+                self.typs.push(typ);
+                TypId(id)
+            }
+        }
+    }
+
+    fn intern_param(&mut self, param: Param) -> ParamId {
+        match self.params.iter().position(|v| *v == param) {
+            Some(id) => ParamId(id),
+            None => {
+                let id = self.params.len();
+                self.params.push(param);
+                ParamId(id)
+            }
+        }
+    }
+
+    fn next_owner_id(&mut self) -> OwnerId {
+        let id = OwnerId(self.next_owner_id);
+        self.next_owner_id += 1;
+        id
+    }
+
+    fn make_rib(&mut self) -> RibId {
+        let id = RibId(self.ribs.len());
+        self.ribs.push(Rib::new(self.rib));
+        id
+    }
+
+    fn rib_mut(&mut self) -> &mut Rib {
+        &mut self.ribs[self.rib.0]
+    }
+
+    fn rib(&self) -> &Rib {
+        &self.ribs[self.rib.0]
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+struct RibId(usize);
+
+#[derive(Debug)]
+struct Rib {
+    parent: Option<RibId>,
+    defs_owner: HashMap<u64, OwnerId>,
+    defs_params: HashMap<u64, Option<ParamId>>,
+}
+
+impl Rib {
+    pub fn new(parent: RibId) -> Self {
+        Self {
+            parent: Some(parent),
+            defs_owner: HashMap::new(),
+            defs_params: HashMap::new(),
+        }
+    }
+
+    pub fn new_root() -> Self {
+        Self {
+            parent: None,
+            defs_owner: HashMap::new(),
+            defs_params: HashMap::new(),
+        }
+    }
+
+    pub fn define_item(&mut self, ident_id: u64, owner_id: OwnerId) -> Result<(), ()> {
+        if self.parent.is_some() && self.defs_owner.contains_key(&ident_id) {
+            return Err(());
+        }
+        self.defs_owner.insert(ident_id, owner_id);
+        self.defs_params.insert(ident_id, None);
+        Ok(())
+    }
+
+    pub fn define_param(&mut self, ident_id: u64, owner_id: OwnerId, param_id: ParamId) {
+        self.defs_owner.insert(ident_id, owner_id);
+        self.defs_params.insert(ident_id, Some(param_id));
+    }
+
+    pub fn ident_owner(&self, ribs: &[Rib], ident_id: u64) -> Option<OwnerId> {
+        if let Some(owner_id) = self.defs_owner.get(&ident_id) {
+            return Some(*owner_id);
+        }
+        let parent_id = self.parent?;
+        ribs[parent_id.0].ident_owner(ribs, ident_id)
+    }
+}

src/hir.rs

@@ -0,0 +1,164 @@
+use std::collections::HashMap;
+
+use crate::pos::Pos;
+
+#[derive(Clone, PartialEq, Debug)]
+pub struct Pack {
+    stmts: Vec<Stmt>,
+    exprs: Vec<Expr>,
+    typs: Vec<Typ>,
+    params: Vec<Param>,
+    owners: HashMap<OwnerId, StmtId>,
+}
+
+impl<'pack> Pack {
+    pub fn new(
+        stmts: Vec<Stmt>,
+        exprs: Vec<Expr>,
+        typs: Vec<Typ>,
+        params: Vec<Param>,
+        owners: HashMap<OwnerId, StmtId>,
+    ) -> Self {
+        Self {
+            stmts,
+            exprs,
+            typs,
+            params,
+            owners,
+        }
+    }
+
+    pub fn stmt(&'pack self, id: StmtId) -> &'pack Stmt {
+        &self.stmts[id.0]
+    }
+
+    pub fn expr(&'pack self, id: ExprId) -> &'pack Expr {
+        &self.exprs[id.0]
+    }
+
+    pub fn typ(&'pack self, id: TypId) -> &'pack Typ {
+        &self.typs[id.0]
+    }
+
+    pub fn param(&'pack self, id: ParamId) -> &'pack Param {
+        &self.params[id.0]
+    }
+}
+
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub struct StmtId(pub usize);
+
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub struct ExprId(pub usize);
+
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub struct TypId(pub usize);
+
+#[derive(Clone, Copy, PartialEq, Debug)]
+pub struct ParamId(pub usize);
+
+#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug)]
+pub struct OwnerId(pub u64);
+
+#[derive(Clone, PartialEq, Debug)]
+pub struct Stmt {
+    pub kind: StmtKind,
+    pub pos: Pos,
+}
+
+impl Stmt {
+    pub fn new(kind: StmtKind, pos: Pos) -> Self {
+        Self { kind, pos }
+    }
+}
+
+#[derive(Clone, PartialEq, Debug)]
+pub enum StmtKind {
+    Error,
+    Let {
+        subject: ParamId,
+        value: ExprId,
+    },
+    Fn {
+        subject_ident_id: u64,
+        params: Vec<ParamId>,
+        return_typ: Option<TypId>,
+        body: ExprId,
+    },
+    Return {
+        expr: Option<ExprId>,
+    },
+    Break {
+        expr: Option<ExprId>,
+    },
+    Assign {
+        subject: ExprId,
+        value: ExprId,
+    },
+    Expr(ExprId),
+}
+
+#[derive(Clone, PartialEq, Debug)]
+pub struct Expr {
+    pub kind: ExprKind,
+    pub pos: Pos,
+}
+
+impl Expr {
+    pub fn new(kind: ExprKind, pos: Pos) -> Self {
+        Self { kind, pos }
+    }
+}
+
+#[derive(Clone, PartialEq, Debug)]
+pub enum ExprKind {
+    Error,
+    Ident {
+        ident_id: u64,
+        owner: OwnerId,
+    },
+    Int(i64),
+    Str(String),
+    Group(ExprId),
+    Block {
+        stmts: Vec<StmtId>,
+        expr: Option<ExprId>,
+    },
+    Call {
+        subject: ExprId,
+        args: Vec<ExprId>,
+    },
+    If {
+        cond: ExprId,
+        truthy: ExprId,
+        falsy: Option<ExprId>,
+    },
+    Loop {
+        body: ExprId,
+    },
+}
+
+#[derive(Clone, PartialEq, Debug)]
+pub struct Typ {
+    pub kind: TypKind,
+    pub pos: Pos,
+}
+
+impl Typ {
+    pub fn new(kind: TypKind, pos: Pos) -> Self {
+        Self { kind, pos }
+    }
+}
+
+#[derive(Clone, PartialEq, Debug)]
+pub enum TypKind {
+    Error,
+    Ident { ident_id: u64, owner: OwnerId },
+}
+
+#[derive(Clone, PartialEq, Debug)]
+pub struct Param {
+    pub subject_ident_id: u64,
+    pub typ: Option<TypId>,
+    pub pos: Pos,
+}

src/lexer.rs

@@ -12,6 +12,7 @@ pub struct Lexer<'a> {
     line: i64,
     col: i64,
     symbols: HashMap<u64, String>,
+    symbol_ids: HashMap<String, u64>,
     keywords: HashMap<String, TokenKind>,
     error_acc: Rc<Mutex<ErrorAcc>>,
 }
@@ -28,6 +29,7 @@ impl<'a> Lexer<'a> {
             line: 1,
             col: 1,
             symbols: HashMap::new(),
+            symbol_ids: HashMap::new(),
             keywords: Self::make_keywords(),
             error_acc,
         }
@@ -71,8 +73,14 @@ impl<'a> Lexer<'a> {
                             if let Some(kind) = self.keywords.get(&value) {
                                 return self.token(kind.clone(), pos);
                             }
-                            let id = self.symbols.len() as u64;
-                            self.symbols.insert(id, value);
+                            let id = if let Some(id) = self.symbol_ids.get(&value) {
+                                *id
+                            } else {
+                                let id = self.symbols.len() as u64;
+                                self.symbols.insert(id, value.clone());
+                                self.symbol_ids.insert(value, id);
+                                id
+                            };
                             break self.token_with_value(
                                 TokenKind::Ident,
                                 TokenValue::Ident(id),
@@ -239,7 +247,7 @@ impl<'a> Lexer<'a> {
     fn error<S: Into<String>>(&mut self, msg: S, pos: Pos) {
         let msg = msg.into();
         self.error_acc.lock().unwrap().add(Error {
-            kind: crate::pos::ErrorKind::LexerError,
+            kind: crate::pos::ErrorKind::Lexer,
             pos: Some(pos),
             msg,
         });

src/main.rs

@@ -2,10 +2,13 @@
 
 use std::{rc::Rc, sync::Mutex};
 
+use ast_lower::AstLower;
 use parser::Parser;
 use pos::{ErrorAcc, Pos};
 
 mod ast;
+mod ast_lower;
+mod hir;
 mod lexer;
 mod parser;
 mod pos;
@@ -19,10 +22,17 @@ fn main() {
     let error_acc = Rc::new(Mutex::new(ErrorAcc::new()));
 
     let mut parser = Parser::new(&text, error_acc.clone());
-
     let ast = parser.parse();
 
-    println!("{ast:#?}");
+    let mut ast_lower = AstLower::new(error_acc.clone());
+    ast_lower.lower_ast(&ast);
+    let pack = ast_lower.pack_it_up();
+
+    println!("text: {text}");
+    // println!("ast: {ast:#?}");
+    // println!("hir: {pack:#?}");
+    let symbols = parser.symbols();
+    println!("symbols: {symbols:#?}");
 
     let error_acc = error_acc.lock().unwrap();
     if !error_acc.ok() {

src/parser.rs

@@ -490,7 +490,7 @@ impl<'a> Parser<'a> {
     fn error<S: Into<String>>(&mut self, msg: S, pos: Pos) {
         let msg = msg.into();
         self.error_acc.lock().unwrap().add(Error {
-            kind: crate::pos::ErrorKind::ParserError,
+            kind: crate::pos::ErrorKind::Parser,
             pos: Some(pos),
             msg,
         });

src/pos.rs

@@ -20,9 +20,9 @@ pub struct Error {
 
 #[derive(Clone, Debug)]
 pub enum ErrorKind {
-    LexerError,
-    ParserError,
-    CheckerError,
+    Lexer,
+    Parser,
+    Checker,
 }
 
 pub struct ErrorAcc {