From da9558c6841e7721fcbecb71da9f860e7a07d004 Mon Sep 17 00:00:00 2001
From: Jeong YunWon <jeong@youknowone.org>
Date: Thu, 10 Jun 2021 12:36:34 +0900
Subject: [PATCH] Remove trivially unnessessary unwrap() from expr

---
 src/uu/expr/src/expr.rs        |  6 +-----
 src/uu/expr/src/syntax_tree.rs | 17 ++++-------------
 2 files changed, 5 insertions(+), 18 deletions(-)

diff --git a/src/uu/expr/src/expr.rs b/src/uu/expr/src/expr.rs
index 329a79ba2..8238917f7 100644
--- a/src/uu/expr/src/expr.rs
+++ b/src/uu/expr/src/expr.rs
@@ -56,11 +56,7 @@ fn print_expr_error(expr_error: &str) -> ! {
 }
 
 fn evaluate_ast(maybe_ast: Result<Box<syntax_tree::AstNode>, String>) -> Result<String, String> {
-    if maybe_ast.is_err() {
-        Err(maybe_ast.err().unwrap())
-    } else {
-        maybe_ast.ok().unwrap().evaluate()
-    }
+    maybe_ast.and_then(|ast| ast.evaluate())
 }
 
 fn maybe_handle_help_or_version(args: &[String]) -> bool {
diff --git a/src/uu/expr/src/syntax_tree.rs b/src/uu/expr/src/syntax_tree.rs
index b72d78729..ba477414e 100644
--- a/src/uu/expr/src/syntax_tree.rs
+++ b/src/uu/expr/src/syntax_tree.rs
@@ -175,23 +175,14 @@ impl AstNode {
 pub fn tokens_to_ast(
     maybe_tokens: Result<Vec<(usize, Token)>, String>,
 ) -> Result<Box<AstNode>, String> {
-    if maybe_tokens.is_err() {
-        Err(maybe_tokens.err().unwrap())
-    } else {
-        let tokens = maybe_tokens.ok().unwrap();
+    maybe_tokens.and_then(|tokens| {
         let mut out_stack: TokenStack = Vec::new();
         let mut op_stack: TokenStack = Vec::new();
 
         for (token_idx, token) in tokens {
-            if let Err(reason) =
-                push_token_to_either_stack(token_idx, &token, &mut out_stack, &mut op_stack)
-            {
-                return Err(reason);
-            }
-        }
-        if let Err(reason) = move_rest_of_ops_to_out(&mut out_stack, &mut op_stack) {
-            return Err(reason);
+            push_token_to_either_stack(token_idx, &token, &mut out_stack, &mut op_stack)?;
         }
+        move_rest_of_ops_to_out(&mut out_stack, &mut op_stack)?;
         assert!(op_stack.is_empty());
 
         maybe_dump_rpn(&out_stack);
@@ -205,7 +196,7 @@ pub fn tokens_to_ast(
             maybe_dump_ast(&result);
             result
         }
-    }
+    })
 }
 
 fn maybe_dump_ast(result: &Result<Box<AstNode>, String>) {