From bdb5f9ad4bd7d645486f26c70010f873355a7082 Mon Sep 17 00:00:00 2001
From: fef <owo@fef.moe>
Date: Fri, 29 Jul 2022 05:32:44 +0200
Subject: [PATCH] add dot operator for member access

---
 src/ast/mod.rs   | 10 ++++++++++
 src/ast/tree.rs  |  2 ++
 src/lex/mod.rs   |  1 +
 src/lex/token.rs |  2 ++
 4 files changed, 15 insertions(+)

diff --git a/src/ast/mod.rs b/src/ast/mod.rs
index 85e1558..ffc0b6e 100644
--- a/src/ast/mod.rs
+++ b/src/ast/mod.rs
@@ -570,6 +570,16 @@ impl Parser {
                         index: Box::new(index),
                     })
                 }
+                token::Kind::Dot => {
+                    // member access
+                    self.lexer.next();
+                    let member = self.lexer.expect_kind(token::Kind::Ident)?;
+                    self.parse_primary_expr_rest(tree::Node::BinaryExpr {
+                        op: Operator::Dot,
+                        lhs: Box::new(start),
+                        rhs: Box::new(tree::Node::Ident(member.raw)),
+                    })
+                }
                 _ => Ok(start),
             }
         } else {
diff --git a/src/ast/tree.rs b/src/ast/tree.rs
index a6d73e1..d0c9eb5 100644
--- a/src/ast/tree.rs
+++ b/src/ast/tree.rs
@@ -74,6 +74,7 @@ pub enum Node {
 
 #[derive(Debug, PartialEq)]
 pub enum Operator {
+    Dot,
     Eq,
     EqEq,
     Bang,
@@ -284,6 +285,7 @@ impl Operator {
 
     pub fn raw(&self) -> &'static str {
         match self {
+            Operator::Dot => ".",
             Operator::Eq => "=",
             Operator::EqEq => "==",
             Operator::BangEq => "!=",
diff --git a/src/lex/mod.rs b/src/lex/mod.rs
index f4d31cf..9a26453 100644
--- a/src/lex/mod.rs
+++ b/src/lex/mod.rs
@@ -79,6 +79,7 @@ impl Iterator for Lexer {
             ']' => self.token_ok(token::Kind::CBracket),
             '(' => self.token_ok(token::Kind::OParen),
             ')' => self.token_ok(token::Kind::CParen),
+            '.' => self.token_ok(token::Kind::Dot),
 
             '=' if self.skip_if_match("=") => self.token_ok(token::Kind::EqEq),
             '=' => self.token_ok(token::Kind::Eq),
diff --git a/src/lex/token.rs b/src/lex/token.rs
index e6bf454..fbc9672 100644
--- a/src/lex/token.rs
+++ b/src/lex/token.rs
@@ -33,6 +33,7 @@ pub enum Kind {
     CParen,
     Comma,
     Semi,
+    Dot,
 
     Eq,
     EqEq,
@@ -183,6 +184,7 @@ impl fmt::Display for Kind {
                 Kind::CParen => "cparen",
                 Kind::Comma => "comma",
                 Kind::Semi => "semi",
+                Kind::Dot => "dot",
 
                 Kind::Eq => "eq",
                 Kind::EqEq => "eqeq",