From 85d6529f0d2ad81ab544b2b68cfbc59fbae98416 Mon Sep 17 00:00:00 2001
From: Hofer-Julian <30049909+Hofer-Julian@users.noreply.github.com>
Date: Fri, 29 Sep 2023 21:57:15 +0200
Subject: [PATCH] chore: Small refactor of `eval.rs` (#10554)

# Description
- Extract long expression in `eval.rs` into variable
- Improve loop in eval.rs

# User-Facing Changes

None
---
 crates/nu-engine/src/eval.rs | 39 ++++++++++++++++++------------------
 1 file changed, 20 insertions(+), 19 deletions(-)

diff --git a/crates/nu-engine/src/eval.rs b/crates/nu-engine/src/eval.rs
index c89ab6e8b..521aaf02c 100644
--- a/crates/nu-engine/src/eval.rs
+++ b/crates/nu-engine/src/eval.rs
@@ -1015,33 +1015,36 @@ pub fn eval_block(
     let num_pipelines = block.len();
 
     for (pipeline_idx, pipeline) in block.pipelines.iter().enumerate() {
-        let mut i = 0;
-
-        while i < pipeline.elements.len() {
+        let mut elements_iter = pipeline.elements.iter().peekable();
+        while let Some(element) = elements_iter.next() {
             let redirect_stderr = redirect_stderr
-                || ((i < pipeline.elements.len() - 1)
-                    && (matches!(
-                        pipeline.elements[i + 1],
+                || (elements_iter.peek().map_or(false, |next_element| {
+                    matches!(
+                        next_element,
                         PipelineElement::Redirection(_, Redirection::Stderr, _)
                             | PipelineElement::Redirection(_, Redirection::StdoutAndStderr, _)
                             | PipelineElement::SeparateRedirection { .. }
-                    )));
+                    )
+                }));
+
+            let redirect_stdout = redirect_stdout
+                || (elements_iter.peek().map_or(false, |next_element| {
+                    matches!(
+                        next_element,
+                        PipelineElement::Redirection(_, Redirection::Stdout, _)
+                            | PipelineElement::Redirection(_, Redirection::StdoutAndStderr, _)
+                            | PipelineElement::Expression(..)
+                            | PipelineElement::SeparateRedirection { .. }
+                    )
+                }));
 
             // if eval internal command failed, it can just make early return with `Err(ShellError)`.
             let eval_result = eval_element_with_input(
                 engine_state,
                 stack,
-                &pipeline.elements[i],
+                element,
                 input,
-                redirect_stdout
-                    || (i != pipeline.elements.len() - 1)
-                        && (matches!(
-                            pipeline.elements[i + 1],
-                            PipelineElement::Redirection(_, Redirection::Stdout, _)
-                                | PipelineElement::Redirection(_, Redirection::StdoutAndStderr, _)
-                                | PipelineElement::Expression(..)
-                                | PipelineElement::SeparateRedirection { .. }
-                        )),
+                redirect_stdout,
                 redirect_stderr,
             );
 
@@ -1073,8 +1076,6 @@ pub fn eval_block(
                     }
                 }
             }
-
-            i += 1;
         }
 
         if pipeline_idx < (num_pipelines) - 1 {