From 2db5c4d0c4357bc015bc578680b479439f436b23 Mon Sep 17 00:00:00 2001
From: Lino Le Van <11367844+lino-levan@users.noreply.github.com>
Date: Fri, 9 Feb 2024 01:49:35 +0100
Subject: [PATCH] fix: associativity in the parser (#24)

* fix: associativity in the parser

* chore: address dave comments part 1
---
 crates/ast/operators.rs              |  1 +
 crates/parser/parse_expr.rs          | 53 +++++++---------------------
 examples/basics/associativity.blight |  6 ++++
 3 files changed, 19 insertions(+), 41 deletions(-)
 create mode 100644 examples/basics/associativity.blight

diff --git a/crates/ast/operators.rs b/crates/ast/operators.rs
index 9f6efc404a82baca560d40d7531ee4a499cc93b7..27cf0b1a837d2f1f40b45af57026cc4700ed50e2 100644
--- a/crates/ast/operators.rs
+++ b/crates/ast/operators.rs
@@ -244,6 +244,7 @@ pub enum OperatorLevel {
     Comma,              // ,
 }
 
+#[derive(PartialEq)]
 pub enum Associativity {
     LeftToRight,
     RightToLeft,
diff --git a/crates/parser/parse_expr.rs b/crates/parser/parse_expr.rs
index f1429fb898767e14792874af6559dbb9e6c0f1f6..f0a1ed29ef2aa43e331f7e227ab984fd39a3701b 100644
--- a/crates/parser/parse_expr.rs
+++ b/crates/parser/parse_expr.rs
@@ -1,5 +1,4 @@
-use ast::Associativity::*;
-use ast::{BinaryOperator, Expr, ExprData, OperatorLevel};
+use ast::{Associativity, BinaryOperator, Expr, ExprData, OperatorLevel};
 use log::Range;
 use miette::Result;
 
@@ -19,25 +18,8 @@ pub fn parse_expr(p: &mut Parser) -> Result<Expr> {
         if let Some(token) = p.peek() {
             if let Some(level) = BinaryOperator::from_token(&token).map(|o| o.level()) {
                 _ = p.next();
-                match level.associativity() {
-                    RightToLeft => {
-                        expr = parse_expr_binary(
-                            p,
-                            BinaryOperator::from_token(&token).unwrap(),
-                            expr,
-                            level,
-                        )?;
-                    }
-                    LeftToRight => {
-                        // TODO(@paperdave): TODO
-                        expr = parse_expr_binary(
-                            p,
-                            BinaryOperator::from_token(&token).unwrap(),
-                            expr,
-                            level,
-                        )?;
-                    }
-                }
+                expr =
+                    parse_expr_binary(p, BinaryOperator::from_token(&token).unwrap(), expr, level)?;
                 continue;
             }
         }
@@ -60,27 +42,16 @@ fn parse_expr_binary(
     loop {
         if let Some(token) = p.peek() {
             if let Some(new_level) = BinaryOperator::from_token(&token).map(|o| o.level()) {
-                if new_level <= level {
+                if (level.associativity() == Associativity::LeftToRight && new_level < level)
+                    || (level.associativity() == Associativity::RightToLeft && new_level <= level)
+                {
                     _ = p.next();
-                    match new_level.associativity() {
-                        RightToLeft => {
-                            right = parse_expr_binary(
-                                p,
-                                BinaryOperator::from_token(&token).unwrap(),
-                                right,
-                                new_level,
-                            )?;
-                        }
-                        LeftToRight => {
-                            // TODO(@paperdave): TODO
-                            right = parse_expr_binary(
-                                p,
-                                BinaryOperator::from_token(&token).unwrap(),
-                                right,
-                                new_level,
-                            )?;
-                        }
-                    }
+                    right = parse_expr_binary(
+                        p,
+                        BinaryOperator::from_token(&token).unwrap(),
+                        right,
+                        new_level,
+                    )?;
                     continue;
                 }
             }
diff --git a/examples/basics/associativity.blight b/examples/basics/associativity.blight
new file mode 100644
index 0000000000000000000000000000000000000000..5bc76df04a89298c5be31f3f45f6b38c383ac986
--- /dev/null
+++ b/examples/basics/associativity.blight
@@ -0,0 +1,6 @@
+let print = @raw("console.log");
+print(1 * 2 * 3);
+print(1 * 2 / 3);
+print(1 + 2 ** 3);
+print(1 ** 2 ** 3);
+print(1 * 2 + 3);
-- 
2.54.0