stmt parse

grammar.txt

@@ -30,9 +30,9 @@
 <fn-args> ::= "(" { <IDENT> { "," } } ")"
 
 
-<if-stmt> ::= "if" <expression> <block> { <else-stmt> }
+<if-stmt> ::= "if" <expression> <block> { <else-part> }
 
-<else-stmt> ::= "else" ( <if-stmt> | <block> )
+<else-part> ::= "else" ( <if-stmt> | <block> )
 
 
 <loop-stmt> ::= "loop" <block>

src/ast.rs

@@ -11,7 +11,10 @@ pub type Symbol = String;
 pub struct Program(pub Vec<Stmt>);
 
 #[derive(Debug, Clone, PartialEq)]
-pub struct Block(pub Vec<Stmt>);
+pub struct Block {
+    pub stmts: Vec<Stmt>,
+    pub span: Span,
+}
 
 #[derive(Debug, Clone, PartialEq)]
 pub enum Stmt {
@@ -19,13 +22,31 @@ pub enum Stmt {
     Assignment(Assignment),
     FnDecl(FnDecl),
     If(IfStmt),
-    Loop(Block),
+    Loop(Block, Span),
     While(WhileStmt),
-    Break(Break),
+    Break(Span),
-    Return(Option<Expr>),
+    Return(Option<Expr>, Span),
+    Block(Block),
     Expr(Expr),
 }
 
+impl Stmt {
+    pub fn span(&self) -> Span {
+        match self {
+            Stmt::Declaration(decl) => decl.span,
+            Stmt::Assignment(assign) => assign.span,
+            Stmt::FnDecl(decl) => decl.span,
+            Stmt::If(if_stmt) => if_stmt.span,
+            Stmt::Loop(_, span) => *span,
+            Stmt::While(while_stmt) => while_stmt.span,
+            Stmt::Break(span) => *span,
+            Stmt::Return(_, span) => *span,
+            Stmt::Block(block) => block.span,
+            Stmt::Expr(expr) => expr.span(),
+        }
+    }
+}
+
 #[derive(Debug, Clone, PartialEq)]
 pub struct Declaration {
     pub span: Span,
@@ -51,15 +72,24 @@ pub struct FnDecl {
 #[derive(Debug, Clone, PartialEq)]
 pub struct IfStmt {
     pub span: Span,
-    pub condition: Expr,
+    pub cond: Expr,
     pub body: Block,
-    pub else_part: Box<ElsePart>,
+    pub else_part: Option<Box<ElsePart>>,
 }
 
 #[derive(Debug, Clone, PartialEq)]
 pub enum ElsePart {
-    Else(Block),
+    Else(Block, Span),
-    ElseIf(IfStmt),
+    ElseIf(IfStmt, Span),
+}
+
+impl ElsePart {
+    pub fn span(&self) -> Span {
+        match self {
+            ElsePart::Else(_, span) => *span,
+            ElsePart::ElseIf(_, span) => *span,
+        }
+    }
 }
 
 #[derive(Debug, Clone, PartialEq)]
@@ -69,11 +99,6 @@ pub struct WhileStmt {
     pub body: Block,
 }
 
-#[derive(Debug, Clone, PartialEq)]
-pub struct Break {
-    pub span: Span,
-}
-
 #[derive(Debug, Clone, PartialEq)]
 pub enum Expr {
     Ident(Symbol, Span),

src/errors.rs

@@ -47,6 +47,15 @@ mod span {
             }
         }
 
+        /// Extends the span by the second one, if it exists
+        /// The other one has to be after the current one, if it exists
+        pub fn option_extend(&self, other: Option<Span>) -> Span {
+            match other {
+                None => *self,
+                Some(span) => self.extend(span),
+            }
+        }
+
         pub fn len(&self) -> usize {
             self.end - self.start
         }

src/lex.rs

@@ -39,6 +39,7 @@ pub enum TokenType<'code> {
     While,
     For,
     Break,
+    Return,
     True,
     False,
     Null,
@@ -326,6 +327,8 @@ fn keyword_or_ident(name: &str) -> TokenType {
         b'w' if len == 5 && bs[1..5] == *b"hile" => TokenType::While,
         // break
         b'b' if len == 5 && bs[1..5] == *b"reak" => TokenType::Break,
+        // return
+        b'r' if len == 6 && bs[1..6] == *b"eturn" => TokenType::Return,
         // true
         b't' if len == 4 && bs[1..4] == *b"rue" => TokenType::True,
         // null && not

src/parse.rs

@@ -1,718 +0,0 @@
-#![allow(dead_code)]
-
-use crate::ast::*;
-use crate::errors::{CompilerError, Span};
-use crate::lex::{Token, TokenType};
-use std::iter::Peekable;
-
-pub fn parse(tokens: Vec<Token>) -> Result<Program, ParseErr> {
-    let mut parser = Parser {
-        tokens: tokens.into_iter().peekable(),
-    };
-    let program = parser.program()?;
-    Ok(program)
-}
-
-#[derive(Debug)]
-struct Parser<'code> {
-    tokens: Peekable<std::vec::IntoIter<Token<'code>>>,
-}
-
-type ParseResult<'code, T> = Result<T, ParseErr<'code>>;
-
-macro_rules! parse_bin_op {
-    ($self: ident, $lhs: ident, $kind: expr, $function: ident) => {{
-        let _ = $self.next();
-        let rhs = $self.$function()?;
-        Ok(Expr::BinaryOp(Box::new(BinaryOp {
-            span: $lhs.span().extend(rhs.span()),
-            lhs: $lhs,
-            rhs,
-            kind: $kind,
-        })))
-    }};
-}
-
-impl<'code> Parser<'code> {
-    fn program(&mut self) -> ParseResult<'code, Program> {
-        Ok(Program(self.statement_list()?))
-    }
-
-    fn statement_list(&mut self) -> ParseResult<'code, Vec<Stmt>> {
-        let mut stmts = Vec::new();
-        loop {
-            if let Some(TokenType::BraceC) | None = self.peek().map(|token| &token.kind) {
-                let _ = self.next();
-                return Ok(stmts);
-            }
-            let stmt = self.statement()?;
-            stmts.push(stmt);
-        }
-    }
-
-    fn block(&mut self) -> ParseResult<'code, Block> {
-        Ok(Block(self.statement_list()?))
-    }
-
-    fn statement(&mut self) -> ParseResult<'code, Stmt> {
-        let expr = self.expression()?;
-        self.expect(TokenType::Semi)?;
-        Ok(Stmt::Expr(expr))
-    }
-
-    fn declaration(&mut self) -> ParseResult<'code, Declaration> {
-        todo!()
-    }
-
-    fn assignment(&mut self) -> ParseResult<'code, Assignment> {
-        todo!()
-    }
-
-    fn fn_decl(&mut self) -> ParseResult<'code, FnDecl> {
-        todo!()
-    }
-
-    fn if_stmt(&mut self) -> ParseResult<'code, IfStmt> {
-        todo!()
-    }
-
-    fn loop_stmt(&mut self) -> ParseResult<'code, Block> {
-        todo!()
-    }
-
-    fn expression(&mut self) -> ParseResult<'code, Expr> {
-        self.logical_or()
-    }
-
-    fn logical_or(&mut self) -> ParseResult<'code, Expr> {
-        let lhs = self.logical_and()?;
-        match self.peek().map(|token| &token.kind) {
-            Some(TokenType::Or) => parse_bin_op!(self, lhs, BinaryOpKind::Or, logical_and),
-            _ => Ok(lhs),
-        }
-    }
-
-    fn logical_and(&mut self) -> ParseResult<'code, Expr> {
-        let lhs = self.equality()?;
-        match self.peek().map(|token| &token.kind) {
-            Some(TokenType::And) => parse_bin_op!(self, lhs, BinaryOpKind::And, equality),
-            _ => Ok(lhs),
-        }
-    }
-
-    fn equality(&mut self) -> ParseResult<'code, Expr> {
-        let lhs = self.comparison()?;
-        match self.peek().map(|token| &token.kind) {
-            Some(TokenType::BangEqual) => {
-                parse_bin_op!(self, lhs, BinaryOpKind::NotEqual, comparison)
-            }
-            Some(TokenType::EqualEqual) => {
-                parse_bin_op!(self, lhs, BinaryOpKind::Equal, comparison)
-            }
-            _ => Ok(lhs),
-        }
-    }
-
-    fn comparison(&mut self) -> ParseResult<'code, Expr> {
-        let lhs = self.term()?;
-        match self.peek().map(|token| &token.kind) {
-            Some(TokenType::Greater) => parse_bin_op!(self, lhs, BinaryOpKind::Greater, term),
-            Some(TokenType::GreaterEqual) => {
-                parse_bin_op!(self, lhs, BinaryOpKind::GreaterEqual, term)
-            }
-            Some(TokenType::Less) => parse_bin_op!(self, lhs, BinaryOpKind::Less, term),
-            Some(TokenType::LessEqual) => {
-                parse_bin_op!(self, lhs, BinaryOpKind::LessEqual, term)
-            }
-            _ => Ok(lhs),
-        }
-    }
-
-    fn term(&mut self) -> ParseResult<'code, Expr> {
-        let lhs = self.factor()?;
-        match self.peek().map(|token| &token.kind) {
-            Some(TokenType::Plus) => parse_bin_op!(self, lhs, BinaryOpKind::Add, factor),
-            Some(TokenType::Minus) => parse_bin_op!(self, lhs, BinaryOpKind::Sub, factor),
-            _ => Ok(lhs),
-        }
-    }
-
-    fn factor(&mut self) -> ParseResult<'code, Expr> {
-        let lhs = self.unary()?;
-        match self.peek().map(|token| &token.kind) {
-            Some(TokenType::Asterisk) => parse_bin_op!(self, lhs, BinaryOpKind::Mul, unary),
-            Some(TokenType::Slash) => parse_bin_op!(self, lhs, BinaryOpKind::Div, unary),
-            Some(TokenType::Percent) => parse_bin_op!(self, lhs, BinaryOpKind::Mod, unary),
-            _ => Ok(lhs),
-        }
-    }
-
-    fn unary(&mut self) -> ParseResult<'code, Expr> {
-        match self.peek().map(|token| &token.kind) {
-            Some(TokenType::Not) => {
-                let unary_op_span = self.next().unwrap().span;
-                let expr = self.expression()?;
-                Ok(Expr::UnaryOp(Box::new(UnaryOp {
-                    span: unary_op_span.extend(expr.span()),
-                    expr,
-                    kind: UnaryOpKind::Not,
-                })))
-            }
-            Some(TokenType::Minus) => {
-                let unary_op_span = self.next().unwrap().span;
-                let expr = self.expression()?;
-                Ok(Expr::UnaryOp(Box::new(UnaryOp {
-                    span: unary_op_span.extend(expr.span()),
-                    expr,
-                    kind: UnaryOpKind::Neg,
-                })))
-            }
-            _ => self.primary(),
-        }
-    }
-
-    fn primary(&mut self) -> ParseResult<'code, Expr> {
-        let next = self.next().ok_or(ParseErr::EOF("primary"))?;
-        match next.kind {
-            TokenType::String(literal) => Ok(Expr::Literal(Literal::String(literal, next.span))),
-            TokenType::Number(literal) => Ok(Expr::Literal(Literal::Number(literal, next.span))),
-            TokenType::False => Ok(Expr::Literal(Literal::Boolean(false, next.span))),
-            TokenType::True => Ok(Expr::Literal(Literal::Boolean(true, next.span))),
-            TokenType::Null => Ok(Expr::Literal(Literal::Null(next.span))),
-            TokenType::BraceO => self.object_literal(next.span),
-            TokenType::BracketO => self.array_literal(next.span),
-            TokenType::ParenO => {
-                let expr = self.expression()?;
-                let _ = self.expect(TokenType::ParenC)?;
-                Ok(expr)
-            }
-            TokenType::Ident(name) => {
-                let name_owned = name.to_owned();
-                Ok(Expr::Ident(name_owned, next.span))
-            }
-            _ => Err(ParseErr::InvalidTokenPrimary(next)),
-        }
-    }
-
-    fn object_literal(&mut self, open_span: Span) -> ParseResult<'code, Expr> {
-        let close_span = self.expect(TokenType::BraceC)?.span;
-        Ok(Expr::Literal(Literal::Object(open_span.extend(close_span))))
-    }
-
-    fn array_literal(&mut self, open_span: Span) -> ParseResult<'code, Expr> {
-        let mut elements = Vec::new();
-        while self
-            .peek()
-            .ok_or(ParseErr::EOFExpecting(TokenType::BracketC))?
-            .kind
-            != TokenType::BracketC
-        {
-            let expr = self.expression()?;
-            elements.push(expr);
-            self.expect(TokenType::Comma)?;
-        }
-        let closing_bracket = self.expect(TokenType::BracketC)?;
-        Ok(Expr::Literal(Literal::Array(
-            elements,
-            open_span.extend(closing_bracket.span),
-        )))
-    }
-
-    // token helpers
-
-    #[must_use]
-    fn next(&mut self) -> Option<Token<'code>> {
-        self.tokens.next()
-    }
-
-    #[must_use]
-    fn peek(&mut self) -> Option<&Token<'code>> {
-        self.tokens.peek()
-    }
-
-    fn expect(&mut self, kind: TokenType<'code>) -> ParseResult<'code, Token> {
-        if let Some(token) = self.next() {
-            if token.kind == kind {
-                Ok(token)
-            } else {
-                Err(ParseErr::MismatchedKind {
-                    expected: kind,
-                    actual: token,
-                })
-            }
-        } else {
-            Err(ParseErr::EOFExpecting(kind))
-        }
-    }
-}
-
-#[derive(Debug)]
-pub enum ParseErr<'code> {
-    MismatchedKind {
-        expected: TokenType<'code>,
-        actual: Token<'code>,
-    },
-    InvalidTokenPrimary(Token<'code>),
-    EOFExpecting(TokenType<'code>),
-    EOF(&'static str),
-}
-
-impl CompilerError for ParseErr<'_> {
-    fn span(&self) -> Span {
-        match self {
-            ParseErr::MismatchedKind {
-                actual: Token { span, .. },
-                ..
-            } => *span,
-            ParseErr::InvalidTokenPrimary(Token { span, .. }) => *span,
-            ParseErr::EOFExpecting(_) => Span::dummy(),
-            ParseErr::EOF(_) => Span::dummy(),
-        }
-    }
-
-    fn message(&self) -> String {
-        match self {
-            ParseErr::MismatchedKind { expected, actual } => {
-                format!("expected: {:?}, received: {:?}", expected, actual.kind)
-            }
-            ParseErr::InvalidTokenPrimary(token) => {
-                format!("invalid token in expression: {:?}", token.kind)
-            }
-            ParseErr::EOFExpecting(token) => {
-                format!("reached EOF searching for: {:?}", token)
-            }
-            ParseErr::EOF(message) => {
-                format!("reached EOF while parsing: {}", message)
-            }
-        }
-    }
-
-    fn note(&self) -> Option<String> {
-        None
-    }
-}
-
-#[cfg(test)]
-mod test {
-    use crate::ast::BinaryOp;
-    use crate::parse::Parser;
-    use prelude::*;
-
-    mod prelude {
-        pub(super) use super::{parser, test_literal_bin_op, test_number_literal, token};
-        pub(super) use crate::ast::{BinaryOp, BinaryOpKind, Expr, Literal};
-        pub(super) use crate::errors::Span;
-        pub(super) use crate::lex::{Token, TokenType};
-    }
-
-    fn token(kind: TokenType) -> Token {
-        Token {
-            span: Span::dummy(),
-            kind,
-        }
-    }
-
-    fn parser(tokens: Vec<Token>) -> Parser {
-        Parser {
-            tokens: tokens.into_iter().peekable(),
-        }
-    }
-
-    fn test_literal_bin_op<F: FnOnce(Vec<Token<'_>>) -> Expr>(
-        token_type: TokenType,
-        expected_op_kind: BinaryOpKind,
-        parser: F,
-    ) {
-        let tokens = [TokenType::Number(10.0), token_type, TokenType::Number(4.0)]
-            .map(token)
-            .into();
-        let factor = parser(tokens);
-        assert_eq!(
-            Expr::BinaryOp(Box::new(BinaryOp {
-                span: Span::dummy(),
-                lhs: Expr::Literal(Literal::Number(10.0, Span::dummy())),
-                rhs: Expr::Literal(Literal::Number(4.0, Span::dummy())),
-                kind: expected_op_kind
-            })),
-            factor
-        );
-    }
-
-    fn test_number_literal<F: FnOnce(Vec<Token<'_>>) -> Expr>(parser: F) {
-        let tokens = [TokenType::Number(10.0)].map(token).into();
-        let unary = parser(tokens);
-        assert_eq!(Expr::Literal(Literal::Number(10.0, Span::dummy())), unary);
-    }
-
-    mod expr {
-        use super::prelude::*;
-        use crate::ast::{UnaryOp, UnaryOpKind};
-        use TokenType::*;
-
-        fn parse_expr(tokens: Vec<Token>) -> Expr {
-            let mut parser = parser(tokens);
-            parser.expression().unwrap()
-        }
-
-        #[test]
-        fn number_literal() {
-            test_number_literal(parse_expr);
-        }
-
-        #[test]
-        fn add_multiply() {
-            let tokens = [Number(10.0), Plus, Number(20.0), Asterisk, Number(100.0)]
-                .map(token)
-                .into();
-            let expr = parse_expr(tokens);
-            assert_eq!(
-                Expr::BinaryOp(Box::new(BinaryOp {
-                    span: Span::dummy(),
-                    lhs: Expr::Literal(Literal::Number(10.0, Span::dummy())),
-                    rhs: Expr::BinaryOp(Box::new(BinaryOp {
-                        span: Span::dummy(),
-                        lhs: Expr::Literal(Literal::Number(20.0, Span::dummy())),
-                        rhs: Expr::Literal(Literal::Number(100.0, Span::dummy())),
-
-                        kind: BinaryOpKind::Mul
-                    })),
-                    kind: BinaryOpKind::Add
-                })),
-                expr
-            );
-        }
-
-        #[test]
-        fn equal_unary() {
-            let tokens = [Number(10.0), EqualEqual, Minus, Number(10.0)]
-                .map(token)
-                .into();
-            let expr = parse_expr(tokens);
-            assert_eq!(
-                Expr::BinaryOp(Box::new(BinaryOp {
-                    span: Span::dummy(),
-                    lhs: Expr::Literal(Literal::Number(10.0, Span::dummy())),
-                    rhs: Expr::UnaryOp(Box::new(UnaryOp {
-                        span: Span::dummy(),
-                        expr: Expr::Literal(Literal::Number(10.0, Span::dummy())),
-                        kind: UnaryOpKind::Neg
-                    })),
-                    kind: BinaryOpKind::Equal
-                })),
-                expr
-            );
-        }
-
-        #[test]
-        fn parentheses_mul_add() {
-            let tokens = [
-                Number(10.0),
-                Asterisk,
-                ParenO,
-                Number(20.0),
-                Plus,
-                Number(30.0),
-                ParenC,
-            ]
-            .map(token)
-            .into();
-            let expr = parse_expr(tokens);
-            assert_eq!(
-                Expr::BinaryOp(Box::new(BinaryOp {
-                    span: Span::dummy(),
-                    lhs: Expr::Literal(Literal::Number(10.0, Span::dummy())),
-                    rhs: Expr::BinaryOp(Box::new(BinaryOp {
-                        span: Span::dummy(),
-                        lhs: Expr::Literal(Literal::Number(20.0, Span::dummy())),
-                        rhs: Expr::Literal(Literal::Number(30.0, Span::dummy())),
-
-                        kind: BinaryOpKind::Add
-                    })),
-                    kind: BinaryOpKind::Mul
-                })),
-                expr
-            );
-        }
-    }
-
-    mod logical_or {
-        use super::prelude::*;
-
-        fn parse_logical_or(tokens: Vec<Token>) -> Expr {
-            let mut parser = parser(tokens);
-            parser.logical_or().unwrap()
-        }
-
-        #[test]
-        fn number_literal() {
-            test_number_literal(parse_logical_or);
-        }
-
-        #[test]
-        fn and() {
-            test_literal_bin_op(TokenType::Or, BinaryOpKind::Or, parse_logical_or);
-        }
-    }
-
-    mod logical_and {
-        use super::prelude::*;
-
-        fn parse_logical_and(tokens: Vec<Token>) -> Expr {
-            let mut parser = parser(tokens);
-            parser.logical_and().unwrap()
-        }
-
-        #[test]
-        fn number_literal() {
-            test_number_literal(parse_logical_and);
-        }
-
-        #[test]
-        fn and() {
-            test_literal_bin_op(TokenType::And, BinaryOpKind::And, parse_logical_and);
-        }
-    }
-
-    mod equality {
-        use super::prelude::*;
-
-        fn parse_equality(tokens: Vec<Token>) -> Expr {
-            let mut parser = parser(tokens);
-            parser.equality().unwrap()
-        }
-
-        #[test]
-        fn number_literal() {
-            test_number_literal(parse_equality);
-        }
-
-        #[test]
-        fn not_equal() {
-            test_literal_bin_op(TokenType::BangEqual, BinaryOpKind::NotEqual, parse_equality);
-        }
-
-        #[test]
-        fn equal() {
-            test_literal_bin_op(TokenType::EqualEqual, BinaryOpKind::Equal, parse_equality);
-        }
-    }
-
-    mod comparison {
-        use super::prelude::*;
-
-        fn parse_comparison(tokens: Vec<Token>) -> Expr {
-            let mut parser = parser(tokens);
-            parser.comparison().unwrap()
-        }
-
-        #[test]
-        fn number_literal() {
-            test_number_literal(parse_comparison);
-        }
-
-        #[test]
-        fn greater() {
-            test_literal_bin_op(TokenType::Greater, BinaryOpKind::Greater, parse_comparison);
-        }
-
-        #[test]
-        fn greater_equal() {
-            test_literal_bin_op(
-                TokenType::GreaterEqual,
-                BinaryOpKind::GreaterEqual,
-                parse_comparison,
-            );
-        }
-
-        #[test]
-        fn less() {
-            test_literal_bin_op(TokenType::Less, BinaryOpKind::Less, parse_comparison);
-        }
-
-        #[test]
-        fn less_equal() {
-            test_literal_bin_op(
-                TokenType::LessEqual,
-                BinaryOpKind::LessEqual,
-                parse_comparison,
-            );
-        }
-    }
-
-    mod term {
-        use super::prelude::*;
-
-        fn parse_term(tokens: Vec<Token>) -> Expr {
-            let mut parser = parser(tokens);
-            parser.term().unwrap()
-        }
-
-        #[test]
-        fn number_literal() {
-            test_number_literal(parse_term);
-        }
-
-        #[test]
-        fn add() {
-            test_literal_bin_op(TokenType::Plus, BinaryOpKind::Add, parse_term);
-        }
-
-        #[test]
-        fn sub() {
-            test_literal_bin_op(TokenType::Minus, BinaryOpKind::Sub, parse_term);
-        }
-    }
-
-    mod factor {
-        use super::prelude::*;
-
-        fn parse_factor(tokens: Vec<Token>) -> Expr {
-            let mut parser = parser(tokens);
-            parser.factor().unwrap()
-        }
-
-        #[test]
-        fn number_literal() {
-            test_number_literal(parse_factor);
-        }
-
-        #[test]
-        fn multiply() {
-            test_literal_bin_op(TokenType::Asterisk, BinaryOpKind::Mul, parse_factor);
-        }
-
-        #[test]
-        fn divide() {
-            test_literal_bin_op(TokenType::Slash, BinaryOpKind::Div, parse_factor);
-        }
-
-        #[test]
-        fn modulo() {
-            test_literal_bin_op(TokenType::Percent, BinaryOpKind::Mod, parse_factor);
-        }
-    }
-
-    mod unary {
-        use super::prelude::*;
-        use crate::ast::{UnaryOp, UnaryOpKind};
-
-        fn parse_unary(tokens: Vec<Token>) -> Expr {
-            let mut parser = parser(tokens);
-            parser.unary().unwrap()
-        }
-
-        #[test]
-        fn number_literal() {
-            test_number_literal(parse_unary);
-        }
-
-        // needs expr support
-
-        #[test]
-        fn not() {
-            let tokens = [TokenType::Not, TokenType::True].map(token).into();
-            let unary = parse_unary(tokens);
-            assert_eq!(
-                Expr::UnaryOp(Box::new(UnaryOp {
-                    span: Span::dummy(),
-                    expr: Expr::Literal(Literal::Boolean(true, Span::dummy())),
-                    kind: UnaryOpKind::Not
-                })),
-                unary
-            );
-        }
-
-        #[test]
-        fn neg() {
-            let tokens = [TokenType::Minus, TokenType::Number(10.0)]
-                .map(token)
-                .into();
-            let unary = parse_unary(tokens);
-            assert_eq!(
-                Expr::UnaryOp(Box::new(UnaryOp {
-                    span: Span::dummy(),
-                    expr: Expr::Literal(Literal::Number(10.0, Span::dummy())),
-                    kind: UnaryOpKind::Neg
-                })),
-                unary
-            );
-        }
-    }
-
-    mod primary {
-        use super::prelude::*;
-
-        fn parse_primary(tokens: Vec<Token>) -> Expr {
-            let mut parser = parser(tokens);
-            parser.primary().unwrap()
-        }
-
-        #[test]
-        fn ident() {
-            let tokens = [TokenType::Ident("tokens")].map(token).into();
-            let literal = parse_primary(tokens);
-            assert_eq!(Expr::Ident("tokens".to_string(), Span::dummy()), literal);
-        }
-
-        #[test]
-        fn string() {
-            let tokens = [TokenType::Number(10.0)].map(token).into();
-            let literal = parse_primary(tokens);
-            assert_eq!(Expr::Literal(Literal::Number(10.0, Span::dummy())), literal);
-        }
-
-        #[test]
-        fn number() {
-            let tokens = [TokenType::String("uwu".to_string())].map(token).into();
-            let literal = parse_primary(tokens);
-            assert_eq!(
-                Expr::Literal(Literal::String("uwu".to_string(), Span::dummy())),
-                literal
-            );
-        }
-
-        #[test]
-        fn empty_object() {
-            let tokens = [TokenType::BraceO, TokenType::BraceC].map(token).into();
-            let literal = parse_primary(tokens);
-            assert_eq!(Expr::Literal(Literal::Object(Span::dummy())), literal);
-        }
-
-        #[test]
-        fn empty_array() {
-            let tokens = [TokenType::BracketO, TokenType::BracketC].map(token).into();
-            let literal = parse_primary(tokens);
-            assert_eq!(
-                Expr::Literal(Literal::Array(Vec::new(), Span::dummy())),
-                literal
-            );
-        }
-
-        #[test]
-        fn r#false() {
-            let tokens = [TokenType::False].map(token).into();
-            let literal = parse_primary(tokens);
-            assert_eq!(
-                Expr::Literal(Literal::Boolean(false, Span::dummy())),
-                literal
-            );
-        }
-
-        #[test]
-        fn r#true() {
-            let tokens = [TokenType::True].map(token).into();
-            let literal = parse_primary(tokens);
-            assert_eq!(
-                Expr::Literal(Literal::Boolean(true, Span::dummy())),
-                literal
-            );
-        }
-
-        #[test]
-        fn null() {
-            let tokens = [TokenType::Null].map(token).into();
-            let literal = parse_primary(tokens);
-            assert_eq!(Expr::Literal(Literal::Null(Span::dummy())), literal);
-        }
-    }
-}

src/parse/mod.rs

@@ -0,0 +1,409 @@
+#![allow(dead_code)]
+
+#[cfg(test)]
+mod test;
+
+use crate::ast::*;
+use crate::errors::{CompilerError, Span};
+use crate::lex::{Token, TokenType};
+use std::iter::Peekable;
+
+pub fn parse(tokens: Vec<Token>) -> Result<Program, ParseErr> {
+    let mut parser = Parser {
+        tokens: tokens.into_iter().peekable(),
+        inside_fn_depth: 0,
+        inside_loop_depth: 0,
+    };
+    let program = parser.program()?;
+    Ok(program)
+}
+
+#[derive(Debug)]
+struct Parser<'code> {
+    tokens: Peekable<std::vec::IntoIter<Token<'code>>>,
+    inside_fn_depth: usize,
+    inside_loop_depth: usize,
+}
+
+type ParseResult<'code, T> = Result<T, ParseErr<'code>>;
+
+macro_rules! parse_bin_op {
+    ($self: ident, $lhs: ident, $kind: expr, $function: ident) => {{
+        let _ = $self.next();
+        let rhs = $self.$function()?;
+        Ok(Expr::BinaryOp(Box::new(BinaryOp {
+            span: $lhs.span().extend(rhs.span()),
+            lhs: $lhs,
+            rhs,
+            kind: $kind,
+        })))
+    }};
+}
+
+impl<'code> Parser<'code> {
+    fn program(&mut self) -> ParseResult<'code, Program> {
+        Ok(Program(self.statement_list()?))
+    }
+
+    fn statement_list(&mut self) -> ParseResult<'code, Vec<Stmt>> {
+        let mut stmts = Vec::new();
+        loop {
+            if let Some(TokenType::BraceC) | None = self.peek_kind() {
+                let _ = self.next();
+                return Ok(stmts);
+            }
+            let stmt = self.statement()?;
+            stmts.push(stmt);
+        }
+    }
+
+    fn block(&mut self) -> ParseResult<'code, Block> {
+        let start_span = self.expect(TokenType::BraceO)?.span;
+        let stmts = self.statement_list()?;
+        let end_span = self.expect(TokenType::BraceC)?.span;
+        Ok(Block {
+            stmts,
+            span: start_span.extend(end_span),
+        })
+    }
+
+    fn statement(&mut self) -> ParseResult<'code, Stmt> {
+        match self.peek_kind().ok_or(ParseErr::EOF("statement"))? {
+            &TokenType::Let => self.declaration(),
+            &TokenType::Fn => self.fn_decl(),
+            &TokenType::If => Ok(Stmt::If(self.if_stmt()?)),
+            &TokenType::Loop => self.loop_stmt(),
+            &TokenType::While => self.while_stmt(),
+            &TokenType::Break => self.break_stmt(),
+            &TokenType::Return => self.return_stmt(),
+            &TokenType::BraceO => Ok(Stmt::Block(self.block()?)),
+            _ => {
+                let expr = self.expression()?;
+                self.expect(TokenType::Semi)?;
+                Ok(Stmt::Expr(expr))
+            }
+        }
+    }
+
+    fn declaration(&mut self) -> ParseResult<'code, Stmt> {
+        todo!()
+    }
+
+    fn assignment(&mut self) -> ParseResult<'code, Stmt> {
+        todo!()
+    }
+
+    fn fn_decl(&mut self) -> ParseResult<'code, Stmt> {
+        todo!()
+    }
+
+    fn if_stmt(&mut self) -> ParseResult<'code, IfStmt> {
+        let keyword_span = self.expect(TokenType::If)?.span;
+        let cond = self.expression()?;
+        let body = self.block()?;
+
+        let else_part = if let Some(TokenType::Else) = self.peek_kind() {
+            Some(self.else_part()?)
+        } else {
+            None
+        };
+
+        Ok(IfStmt {
+            span: keyword_span
+                .extend(body.span)
+                .option_extend(else_part.as_ref().map(|part| part.span())),
+            cond,
+            body,
+            else_part: else_part.map(Box::new),
+        })
+    }
+
+    fn else_part(&mut self) -> ParseResult<'code, ElsePart> {
+        let keyword_span = self.expect(TokenType::Else)?.span;
+
+        if let Some(TokenType::If) = self.peek_kind() {
+            let else_if_stmt = self.if_stmt()?;
+            let else_span = keyword_span.extend(else_if_stmt.span);
+            Ok(ElsePart::ElseIf(else_if_stmt, else_span))
+        } else {
+            let block = self.block()?;
+            let else_span = keyword_span.extend(block.span);
+            Ok(ElsePart::Else(block, else_span))
+        }
+    }
+
+    fn loop_stmt(&mut self) -> ParseResult<'code, Stmt> {
+        let keyword_span = self.expect(TokenType::Loop)?.span;
+
+        self.inside_loop_depth += 1;
+        let block = self.block()?;
+        self.inside_loop_depth -= 1;
+
+        let loop_span = keyword_span.extend(block.span);
+        Ok(Stmt::Loop(block, keyword_span.extend(loop_span)))
+    }
+
+    fn while_stmt(&mut self) -> ParseResult<'code, Stmt> {
+        let keyword_span = self.expect(TokenType::While)?.span;
+        let cond = self.expression()?;
+        let body = self.block()?;
+        Ok(Stmt::While(WhileStmt {
+            span: keyword_span.extend(body.span),
+            cond,
+            body,
+        }))
+    }
+
+    fn break_stmt(&mut self) -> ParseResult<'code, Stmt> {
+        let keyword_span = self.expect(TokenType::Break)?.span;
+        let semi_span = self.expect(TokenType::Semi)?.span;
+
+        if self.inside_loop_depth == 0 {
+            Err(ParseErr::BreakOutsideLoop(keyword_span.extend(semi_span)))
+        } else {
+            Ok(Stmt::Break(keyword_span.extend(semi_span)))
+        }
+    }
+
+    fn return_stmt(&mut self) -> ParseResult<'code, Stmt> {
+        let keyword_span = self.expect(TokenType::Return)?.span;
+
+        let expr = if let Some(TokenType::Semi) = self.peek_kind() {
+            None
+        } else {
+            Some(self.expression()?)
+        };
+
+        let semi_span = self.expect(TokenType::Semi)?.span;
+
+        if self.inside_fn_depth == 0 {
+            Err(ParseErr::ReturnOutsideFunction(
+                keyword_span.extend(semi_span),
+            ))
+        } else {
+            Ok(Stmt::Return(expr, keyword_span.extend(semi_span)))
+        }
+    }
+
+    fn expression(&mut self) -> ParseResult<'code, Expr> {
+        self.logical_or()
+    }
+
+    fn logical_or(&mut self) -> ParseResult<'code, Expr> {
+        let lhs = self.logical_and()?;
+        match self.peek_kind() {
+            Some(TokenType::Or) => parse_bin_op!(self, lhs, BinaryOpKind::Or, logical_and),
+            _ => Ok(lhs),
+        }
+    }
+
+    fn logical_and(&mut self) -> ParseResult<'code, Expr> {
+        let lhs = self.equality()?;
+        match self.peek_kind() {
+            Some(TokenType::And) => parse_bin_op!(self, lhs, BinaryOpKind::And, equality),
+            _ => Ok(lhs),
+        }
+    }
+
+    fn equality(&mut self) -> ParseResult<'code, Expr> {
+        let lhs = self.comparison()?;
+        match self.peek_kind() {
+            Some(TokenType::BangEqual) => {
+                parse_bin_op!(self, lhs, BinaryOpKind::NotEqual, comparison)
+            }
+            Some(TokenType::EqualEqual) => {
+                parse_bin_op!(self, lhs, BinaryOpKind::Equal, comparison)
+            }
+            _ => Ok(lhs),
+        }
+    }
+
+    fn comparison(&mut self) -> ParseResult<'code, Expr> {
+        let lhs = self.term()?;
+        match self.peek_kind() {
+            Some(TokenType::Greater) => parse_bin_op!(self, lhs, BinaryOpKind::Greater, term),
+            Some(TokenType::GreaterEqual) => {
+                parse_bin_op!(self, lhs, BinaryOpKind::GreaterEqual, term)
+            }
+            Some(TokenType::Less) => parse_bin_op!(self, lhs, BinaryOpKind::Less, term),
+            Some(TokenType::LessEqual) => {
+                parse_bin_op!(self, lhs, BinaryOpKind::LessEqual, term)
+            }
+            _ => Ok(lhs),
+        }
+    }
+
+    fn term(&mut self) -> ParseResult<'code, Expr> {
+        let lhs = self.factor()?;
+        match self.peek_kind() {
+            Some(TokenType::Plus) => parse_bin_op!(self, lhs, BinaryOpKind::Add, factor),
+            Some(TokenType::Minus) => parse_bin_op!(self, lhs, BinaryOpKind::Sub, factor),
+            _ => Ok(lhs),
+        }
+    }
+
+    fn factor(&mut self) -> ParseResult<'code, Expr> {
+        let lhs = self.unary()?;
+        match self.peek_kind() {
+            Some(TokenType::Asterisk) => parse_bin_op!(self, lhs, BinaryOpKind::Mul, unary),
+            Some(TokenType::Slash) => parse_bin_op!(self, lhs, BinaryOpKind::Div, unary),
+            Some(TokenType::Percent) => parse_bin_op!(self, lhs, BinaryOpKind::Mod, unary),
+            _ => Ok(lhs),
+        }
+    }
+
+    fn unary(&mut self) -> ParseResult<'code, Expr> {
+        match self.peek_kind() {
+            Some(TokenType::Not) => {
+                let unary_op_span = self.next().unwrap().span;
+                let expr = self.expression()?;
+                Ok(Expr::UnaryOp(Box::new(UnaryOp {
+                    span: unary_op_span.extend(expr.span()),
+                    expr,
+                    kind: UnaryOpKind::Not,
+                })))
+            }
+            Some(TokenType::Minus) => {
+                let unary_op_span = self.next().unwrap().span;
+                let expr = self.expression()?;
+                Ok(Expr::UnaryOp(Box::new(UnaryOp {
+                    span: unary_op_span.extend(expr.span()),
+                    expr,
+                    kind: UnaryOpKind::Neg,
+                })))
+            }
+            _ => self.primary(),
+        }
+    }
+
+    fn primary(&mut self) -> ParseResult<'code, Expr> {
+        let next = self.next().ok_or(ParseErr::EOF("primary"))?;
+        match next.kind {
+            TokenType::String(literal) => Ok(Expr::Literal(Literal::String(literal, next.span))),
+            TokenType::Number(literal) => Ok(Expr::Literal(Literal::Number(literal, next.span))),
+            TokenType::False => Ok(Expr::Literal(Literal::Boolean(false, next.span))),
+            TokenType::True => Ok(Expr::Literal(Literal::Boolean(true, next.span))),
+            TokenType::Null => Ok(Expr::Literal(Literal::Null(next.span))),
+            TokenType::BraceO => self.object_literal(next.span),
+            TokenType::BracketO => self.array_literal(next.span),
+            TokenType::ParenO => {
+                let expr = self.expression()?;
+                let _ = self.expect(TokenType::ParenC)?;
+                Ok(expr)
+            }
+            TokenType::Ident(name) => {
+                let name_owned = name.to_owned();
+                Ok(Expr::Ident(name_owned, next.span))
+            }
+            _ => Err(ParseErr::InvalidTokenPrimary(next)),
+        }
+    }
+
+    fn object_literal(&mut self, open_span: Span) -> ParseResult<'code, Expr> {
+        let close_span = self.expect(TokenType::BraceC)?.span;
+        Ok(Expr::Literal(Literal::Object(open_span.extend(close_span))))
+    }
+
+    fn array_literal(&mut self, open_span: Span) -> ParseResult<'code, Expr> {
+        let mut elements = Vec::new();
+        while self
+            .peek()
+            .ok_or(ParseErr::EOFExpecting(TokenType::BracketC))?
+            .kind
+            != TokenType::BracketC
+        {
+            let expr = self.expression()?;
+            elements.push(expr);
+            self.expect(TokenType::Comma)?;
+        }
+        let closing_bracket = self.expect(TokenType::BracketC)?;
+        Ok(Expr::Literal(Literal::Array(
+            elements,
+            open_span.extend(closing_bracket.span),
+        )))
+    }
+
+    // token helpers
+
+    #[must_use]
+    fn next(&mut self) -> Option<Token<'code>> {
+        self.tokens.next()
+    }
+
+    #[must_use]
+    fn peek(&mut self) -> Option<&Token<'code>> {
+        self.tokens.peek()
+    }
+
+    #[must_use]
+    fn peek_kind(&mut self) -> Option<&TokenType<'code>> {
+        self.peek().map(|token| &token.kind)
+    }
+
+    fn expect(&mut self, kind: TokenType<'code>) -> ParseResult<'code, Token> {
+        if let Some(token) = self.next() {
+            if token.kind == kind {
+                Ok(token)
+            } else {
+                Err(ParseErr::MismatchedKind {
+                    expected: kind,
+                    actual: token,
+                })
+            }
+        } else {
+            Err(ParseErr::EOFExpecting(kind))
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum ParseErr<'code> {
+    BreakOutsideLoop(Span),
+    ReturnOutsideFunction(Span),
+    MismatchedKind {
+        expected: TokenType<'code>,
+        actual: Token<'code>,
+    },
+    InvalidTokenPrimary(Token<'code>),
+    EOFExpecting(TokenType<'code>),
+    EOF(&'static str),
+}
+
+impl CompilerError for ParseErr<'_> {
+    fn span(&self) -> Span {
+        match self {
+            ParseErr::MismatchedKind {
+                actual: Token { span, .. },
+                ..
+            } => *span,
+            ParseErr::InvalidTokenPrimary(Token { span, .. }) => *span,
+            ParseErr::EOFExpecting(_) => Span::dummy(),
+            ParseErr::EOF(_) => Span::dummy(),
+            ParseErr::BreakOutsideLoop(span) => *span,
+            ParseErr::ReturnOutsideFunction(span) => *span,
+        }
+    }
+
+    fn message(&self) -> String {
+        match self {
+            ParseErr::MismatchedKind { expected, actual } => {
+                format!("expected: {:?}, received: {:?}", expected, actual.kind)
+            }
+            ParseErr::InvalidTokenPrimary(token) => {
+                format!("invalid token in expression: {:?}", token.kind)
+            }
+            ParseErr::EOFExpecting(token) => {
+                format!("reached EOF searching for: {:?}", token)
+            }
+            ParseErr::EOF(message) => {
+                format!("reached EOF while parsing: {}", message)
+            }
+            ParseErr::BreakOutsideLoop(_) => "break used outside of loop".to_string(),
+            ParseErr::ReturnOutsideFunction(_) => "return used outside of function".to_string(),
+        }
+    }
+
+    fn note(&self) -> Option<String> {
+        None
+    }
+}

src/parse/test.rs

@@ -0,0 +1,423 @@
+use crate::ast::BinaryOp;
+use crate::parse::Parser;
+use prelude::*;
+
+mod prelude {
+    pub(super) use super::{parser, test_literal_bin_op, test_number_literal, token};
+    pub(super) use crate::ast::{BinaryOp, BinaryOpKind, Expr, Literal};
+    pub(super) use crate::errors::Span;
+    pub(super) use crate::lex::{Token, TokenType};
+}
+
+fn token(kind: TokenType) -> Token {
+    Token {
+        span: Span::dummy(),
+        kind,
+    }
+}
+
+fn parser(tokens: Vec<Token>) -> Parser {
+    Parser {
+        tokens: tokens.into_iter().peekable(),
+        inside_fn_depth: 0,
+        inside_loop_depth: 0,
+    }
+}
+
+fn test_literal_bin_op<F: FnOnce(Vec<Token<'_>>) -> Expr>(
+    token_type: TokenType,
+    expected_op_kind: BinaryOpKind,
+    parser: F,
+) {
+    let tokens = [TokenType::Number(10.0), token_type, TokenType::Number(4.0)]
+        .map(token)
+        .into();
+    let factor = parser(tokens);
+    assert_eq!(
+        Expr::BinaryOp(Box::new(BinaryOp {
+            span: Span::dummy(),
+            lhs: Expr::Literal(Literal::Number(10.0, Span::dummy())),
+            rhs: Expr::Literal(Literal::Number(4.0, Span::dummy())),
+            kind: expected_op_kind
+        })),
+        factor
+    );
+}
+
+fn test_number_literal<F: FnOnce(Vec<Token<'_>>) -> Expr>(parser: F) {
+    let tokens = [TokenType::Number(10.0)].map(token).into();
+    let unary = parser(tokens);
+    assert_eq!(Expr::Literal(Literal::Number(10.0, Span::dummy())), unary);
+}
+
+mod expr {
+    use super::prelude::*;
+    use crate::ast::{UnaryOp, UnaryOpKind};
+    use TokenType::*;
+
+    fn parse_expr(tokens: Vec<Token>) -> Expr {
+        let mut parser = parser(tokens);
+        parser.expression().unwrap()
+    }
+
+    #[test]
+    fn number_literal() {
+        test_number_literal(parse_expr);
+    }
+
+    #[test]
+    fn add_multiply() {
+        let tokens = [Number(10.0), Plus, Number(20.0), Asterisk, Number(100.0)]
+            .map(token)
+            .into();
+        let expr = parse_expr(tokens);
+        assert_eq!(
+            Expr::BinaryOp(Box::new(BinaryOp {
+                span: Span::dummy(),
+                lhs: Expr::Literal(Literal::Number(10.0, Span::dummy())),
+                rhs: Expr::BinaryOp(Box::new(BinaryOp {
+                    span: Span::dummy(),
+                    lhs: Expr::Literal(Literal::Number(20.0, Span::dummy())),
+                    rhs: Expr::Literal(Literal::Number(100.0, Span::dummy())),
+
+                    kind: BinaryOpKind::Mul
+                })),
+                kind: BinaryOpKind::Add
+            })),
+            expr
+        );
+    }
+
+    #[test]
+    fn equal_unary() {
+        let tokens = [Number(10.0), EqualEqual, Minus, Number(10.0)]
+            .map(token)
+            .into();
+        let expr = parse_expr(tokens);
+        assert_eq!(
+            Expr::BinaryOp(Box::new(BinaryOp {
+                span: Span::dummy(),
+                lhs: Expr::Literal(Literal::Number(10.0, Span::dummy())),
+                rhs: Expr::UnaryOp(Box::new(UnaryOp {
+                    span: Span::dummy(),
+                    expr: Expr::Literal(Literal::Number(10.0, Span::dummy())),
+                    kind: UnaryOpKind::Neg
+                })),
+                kind: BinaryOpKind::Equal
+            })),
+            expr
+        );
+    }
+
+    #[test]
+    fn parentheses_mul_add() {
+        let tokens = [
+            Number(10.0),
+            Asterisk,
+            ParenO,
+            Number(20.0),
+            Plus,
+            Number(30.0),
+            ParenC,
+        ]
+        .map(token)
+        .into();
+        let expr = parse_expr(tokens);
+        assert_eq!(
+            Expr::BinaryOp(Box::new(BinaryOp {
+                span: Span::dummy(),
+                lhs: Expr::Literal(Literal::Number(10.0, Span::dummy())),
+                rhs: Expr::BinaryOp(Box::new(BinaryOp {
+                    span: Span::dummy(),
+                    lhs: Expr::Literal(Literal::Number(20.0, Span::dummy())),
+                    rhs: Expr::Literal(Literal::Number(30.0, Span::dummy())),
+
+                    kind: BinaryOpKind::Add
+                })),
+                kind: BinaryOpKind::Mul
+            })),
+            expr
+        );
+    }
+}
+
+mod logical_or {
+    use super::prelude::*;
+
+    fn parse_logical_or(tokens: Vec<Token>) -> Expr {
+        let mut parser = parser(tokens);
+        parser.logical_or().unwrap()
+    }
+
+    #[test]
+    fn number_literal() {
+        test_number_literal(parse_logical_or);
+    }
+
+    #[test]
+    fn and() {
+        test_literal_bin_op(TokenType::Or, BinaryOpKind::Or, parse_logical_or);
+    }
+}
+
+mod logical_and {
+    use super::prelude::*;
+
+    fn parse_logical_and(tokens: Vec<Token>) -> Expr {
+        let mut parser = parser(tokens);
+        parser.logical_and().unwrap()
+    }
+
+    #[test]
+    fn number_literal() {
+        test_number_literal(parse_logical_and);
+    }
+
+    #[test]
+    fn and() {
+        test_literal_bin_op(TokenType::And, BinaryOpKind::And, parse_logical_and);
+    }
+}
+
+mod equality {
+    use super::prelude::*;
+
+    fn parse_equality(tokens: Vec<Token>) -> Expr {
+        let mut parser = parser(tokens);
+        parser.equality().unwrap()
+    }
+
+    #[test]
+    fn number_literal() {
+        test_number_literal(parse_equality);
+    }
+
+    #[test]
+    fn not_equal() {
+        test_literal_bin_op(TokenType::BangEqual, BinaryOpKind::NotEqual, parse_equality);
+    }
+
+    #[test]
+    fn equal() {
+        test_literal_bin_op(TokenType::EqualEqual, BinaryOpKind::Equal, parse_equality);
+    }
+}
+
+mod comparison {
+    use super::prelude::*;
+
+    fn parse_comparison(tokens: Vec<Token>) -> Expr {
+        let mut parser = parser(tokens);
+        parser.comparison().unwrap()
+    }
+
+    #[test]
+    fn number_literal() {
+        test_number_literal(parse_comparison);
+    }
+
+    #[test]
+    fn greater() {
+        test_literal_bin_op(TokenType::Greater, BinaryOpKind::Greater, parse_comparison);
+    }
+
+    #[test]
+    fn greater_equal() {
+        test_literal_bin_op(
+            TokenType::GreaterEqual,
+            BinaryOpKind::GreaterEqual,
+            parse_comparison,
+        );
+    }
+
+    #[test]
+    fn less() {
+        test_literal_bin_op(TokenType::Less, BinaryOpKind::Less, parse_comparison);
+    }
+
+    #[test]
+    fn less_equal() {
+        test_literal_bin_op(
+            TokenType::LessEqual,
+            BinaryOpKind::LessEqual,
+            parse_comparison,
+        );
+    }
+}
+
+mod term {
+    use super::prelude::*;
+
+    fn parse_term(tokens: Vec<Token>) -> Expr {
+        let mut parser = parser(tokens);
+        parser.term().unwrap()
+    }
+
+    #[test]
+    fn number_literal() {
+        test_number_literal(parse_term);
+    }
+
+    #[test]
+    fn add() {
+        test_literal_bin_op(TokenType::Plus, BinaryOpKind::Add, parse_term);
+    }
+
+    #[test]
+    fn sub() {
+        test_literal_bin_op(TokenType::Minus, BinaryOpKind::Sub, parse_term);
+    }
+}
+
+mod factor {
+    use super::prelude::*;
+
+    fn parse_factor(tokens: Vec<Token>) -> Expr {
+        let mut parser = parser(tokens);
+        parser.factor().unwrap()
+    }
+
+    #[test]
+    fn number_literal() {
+        test_number_literal(parse_factor);
+    }
+
+    #[test]
+    fn multiply() {
+        test_literal_bin_op(TokenType::Asterisk, BinaryOpKind::Mul, parse_factor);
+    }
+
+    #[test]
+    fn divide() {
+        test_literal_bin_op(TokenType::Slash, BinaryOpKind::Div, parse_factor);
+    }
+
+    #[test]
+    fn modulo() {
+        test_literal_bin_op(TokenType::Percent, BinaryOpKind::Mod, parse_factor);
+    }
+}
+
+mod unary {
+    use super::prelude::*;
+    use crate::ast::{UnaryOp, UnaryOpKind};
+
+    fn parse_unary(tokens: Vec<Token>) -> Expr {
+        let mut parser = parser(tokens);
+        parser.unary().unwrap()
+    }
+
+    #[test]
+    fn number_literal() {
+        test_number_literal(parse_unary);
+    }
+
+    // needs expr support
+
+    #[test]
+    fn not() {
+        let tokens = [TokenType::Not, TokenType::True].map(token).into();
+        let unary = parse_unary(tokens);
+        assert_eq!(
+            Expr::UnaryOp(Box::new(UnaryOp {
+                span: Span::dummy(),
+                expr: Expr::Literal(Literal::Boolean(true, Span::dummy())),
+                kind: UnaryOpKind::Not
+            })),
+            unary
+        );
+    }
+
+    #[test]
+    fn neg() {
+        let tokens = [TokenType::Minus, TokenType::Number(10.0)]
+            .map(token)
+            .into();
+        let unary = parse_unary(tokens);
+        assert_eq!(
+            Expr::UnaryOp(Box::new(UnaryOp {
+                span: Span::dummy(),
+                expr: Expr::Literal(Literal::Number(10.0, Span::dummy())),
+                kind: UnaryOpKind::Neg
+            })),
+            unary
+        );
+    }
+}
+
+mod primary {
+    use super::prelude::*;
+
+    fn parse_primary(tokens: Vec<Token>) -> Expr {
+        let mut parser = parser(tokens);
+        parser.primary().unwrap()
+    }
+
+    #[test]
+    fn ident() {
+        let tokens = [TokenType::Ident("tokens")].map(token).into();
+        let literal = parse_primary(tokens);
+        assert_eq!(Expr::Ident("tokens".to_string(), Span::dummy()), literal);
+    }
+
+    #[test]
+    fn string() {
+        let tokens = [TokenType::Number(10.0)].map(token).into();
+        let literal = parse_primary(tokens);
+        assert_eq!(Expr::Literal(Literal::Number(10.0, Span::dummy())), literal);
+    }
+
+    #[test]
+    fn number() {
+        let tokens = [TokenType::String("uwu".to_string())].map(token).into();
+        let literal = parse_primary(tokens);
+        assert_eq!(
+            Expr::Literal(Literal::String("uwu".to_string(), Span::dummy())),
+            literal
+        );
+    }
+
+    #[test]
+    fn empty_object() {
+        let tokens = [TokenType::BraceO, TokenType::BraceC].map(token).into();
+        let literal = parse_primary(tokens);
+        assert_eq!(Expr::Literal(Literal::Object(Span::dummy())), literal);
+    }
+
+    #[test]
+    fn empty_array() {
+        let tokens = [TokenType::BracketO, TokenType::BracketC].map(token).into();
+        let literal = parse_primary(tokens);
+        assert_eq!(
+            Expr::Literal(Literal::Array(Vec::new(), Span::dummy())),
+            literal
+        );
+    }
+
+    #[test]
+    fn r#false() {
+        let tokens = [TokenType::False].map(token).into();
+        let literal = parse_primary(tokens);
+        assert_eq!(
+            Expr::Literal(Literal::Boolean(false, Span::dummy())),
+            literal
+        );
+    }
+
+    #[test]
+    fn r#true() {
+        let tokens = [TokenType::True].map(token).into();
+        let literal = parse_primary(tokens);
+        assert_eq!(
+            Expr::Literal(Literal::Boolean(true, Span::dummy())),
+            literal
+        );
+    }
+
+    #[test]
+    fn null() {
+        let tokens = [TokenType::Null].map(token).into();
+        let literal = parse_primary(tokens);
+        assert_eq!(Expr::Literal(Literal::Null(Span::dummy())), literal);
+    }
+}