From d122827a30de9b0bb5c0cdcfe7f338eb036145db Mon Sep 17 00:00:00 2001
From: JT <547158+jntrnr@users.noreply.github.com>
Date: Fri, 25 Mar 2022 16:23:08 +1300
Subject: [PATCH] Fix operator precedence parser (#4947)

---
 crates/nu-command/tests/commands/math/mod.rs | 24 ++++++++++++++++++++
 crates/nu-parser/src/parser.rs               | 10 +++++++-
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/crates/nu-command/tests/commands/math/mod.rs b/crates/nu-command/tests/commands/math/mod.rs
index 01a60556a..d8e810974 100644
--- a/crates/nu-command/tests/commands/math/mod.rs
+++ b/crates/nu-command/tests/commands/math/mod.rs
@@ -67,6 +67,30 @@ fn precedence_of_operators2() {
     assert_eq!(actual.out, "6");
 }
 
+#[test]
+fn precedence_of_operators3() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            5 - 5 * 10 + 5
+        "#
+    ));
+
+    assert_eq!(actual.out, "-40");
+}
+
+#[test]
+fn precedence_of_operators4() {
+    let actual = nu!(
+        cwd: "tests/fixtures/formats", pipeline(
+        r#"
+            5 - (5 * 10) + 5
+        "#
+    ));
+
+    assert_eq!(actual.out, "-40");
+}
+
 #[test]
 fn division_of_ints() {
     let actual = nu!(
diff --git a/crates/nu-parser/src/parser.rs b/crates/nu-parser/src/parser.rs
index 2ea697d9c..97e9cbf95 100644
--- a/crates/nu-parser/src/parser.rs
+++ b/crates/nu-parser/src/parser.rs
@@ -4019,7 +4019,7 @@ pub fn parse_math_expression(
         );
         error = error.or(err);
 
-        if op_prec <= last_prec && expr_stack.len() > 1 {
+        while op_prec <= last_prec && expr_stack.len() > 1 {
             // Collapse the right associated operations first
             // so that we can get back to a stack with a lower precedence
             let mut rhs = expr_stack
@@ -4029,6 +4029,14 @@ pub fn parse_math_expression(
                 .pop()
                 .expect("internal error: expression stack empty");
 
+            last_prec = op.precedence();
+
+            if last_prec < op_prec {
+                expr_stack.push(op);
+                expr_stack.push(rhs);
+                break;
+            }
+
             let mut lhs = expr_stack
                 .pop()
                 .expect("internal error: expression stack empty");