diff --git a/README.md b/README.md
index 34ff865..7f8dde6 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@
 # zhconv-rs 中文简繁及地區詞轉換
 zhconv-rs converts Chinese text among traditional/simplified scripts or regional variants (e.g. `zh-TW <-> zh-CN <-> zh-HK <-> zh-Hans <-> zh-Hant`), built on the top of rulesets from MediaWiki/Wikipedia and OpenCC.
 
-The implementation is powered by an [Aho-Corasick](https://github.com/daac-tools/daachorse) automaton, ensuring linear time complexity with respect to the length of input text and conversion rules (`O(n+m)`), processing dozens of MiBs text per second.
+The implementation is powered by the [Aho-Corasick](https://github.com/daac-tools/daachorse) algorithm, ensuring linear time complexity with respect to the length of input text and conversion rules (`O(n+m)`), processing dozens of MiBs text per second.
 
 🔗 **Web App: https://zhconv.pages.dev** (powered by WASM)
 
diff --git a/build.rs b/build.rs
index b93fbd8..e347ef7 100644
--- a/build.rs
+++ b/build.rs
@@ -1,7 +1,6 @@
 use std::collections::HashMap;
 
 use std::collections::HashSet;
-use std::convert::TryInto;
 use std::env;
 use std::fs::{self, File};
 use std::io;
@@ -358,7 +357,6 @@ mod opencc {
     use daachorse::{
         CharwiseDoubleArrayAhoCorasick, CharwiseDoubleArrayAhoCorasickBuilder, MatchKind,
     };
-    use itertools::Itertools;
     // use aho_corasick::{AhoCorasick, AhoCorasickBuilder, MatchKind};
     use lazy_static::lazy_static;
     use std::collections::HashMap;
@@ -429,7 +427,7 @@ mod opencc {
         s: &str,
     ) {
         for line in s.lines().map(|l| l.trim()).filter(|l| !l.is_empty()) {
-            if let Some((f, ts)) =  line.split_once(char::is_whitespace){
+            if let Some((f, ts)) = line.split_once(char::is_whitespace) {
                 if f.is_empty() || ts.is_empty() {
                     continue;
                 }
@@ -528,5 +526,5 @@ fn read_and_validate_file(path: &str, sha256sum: &[u8; 32]) -> String {
 fn sha256(text: &str) -> [u8; 32] {
     let mut hasher = Sha256::new();
     hasher.update(text.as_bytes());
-    hasher.finalize().try_into().unwrap()
+    hasher.finalize().into()
 }
diff --git a/src/converter.rs b/src/converter.rs
index 678d422..28ccb2b 100644
--- a/src/converter.rs
+++ b/src/converter.rs
@@ -11,7 +11,7 @@ use crate::{
     pagerules::PageRules,
     rule::{Conv, ConvAction, ConvRule},
     tables::expand_table,
-    utils::{regex, unwrap_or_return},
+    utils::regex,
     variant::Variant,
 };
 
@@ -98,10 +98,13 @@ impl ZhConverter {
 
     /// Same as `convert`, except that it takes a `&mut String` as dest instead of returning a `String`.
     pub fn convert_to(&self, text: &str, output: &mut String) {
-        let automaton = unwrap_or_return!(self.automaton.as_ref().or_else(|| {
-            output.push_str(text);
-            None
-        }));
+        let automaton = match self.automaton.as_ref() {
+            Some(automaton) => automaton,
+            None => {
+                output.push_str(text);
+                return;
+            }
+        };
 
         // Ref: https://github.dev/rust-lang/regex/blob/5197f21287344d2994f9cf06758a3ea30f5a26c3/src/re_trait.rs#L192
         let mut last = 0;
@@ -186,10 +189,13 @@ impl ZhConverter {
         shadowing_target_words: &[String],
         shadowed_source_words: &HashSet<String>,
     ) {
-        let automaton = unwrap_or_return!(self.automaton.as_ref().or_else(|| {
-            output.push_str(text);
-            None
-        }));
+        let automaton = match self.automaton.as_ref() {
+            Some(automaton) => automaton,
+            None => {
+                output.push_str(text);
+                return;
+            }
+        };
 
         // let mut cnt = HashMap::<usize, usize>::new();
         let mut last = 0;
diff --git a/src/utils.rs b/src/utils.rs
index b768aba..2438fca 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -36,19 +36,19 @@ macro_rules! regex {
 }
 pub(crate) use regex;
 
-// https://stackoverflow.com/a/51345372/5488616
-macro_rules! unwrap_or_return {
-    ( $e:expr ) => {
-        match $e {
-            Some(x) => x,
-            None => return,
-        }
-    };
-    ( $e:expr, $r:expr ) => {
-        match $e {
-            Some(x) => x,
-            None => return $r,
-        }
-    };
-}
-pub(crate) use unwrap_or_return;
+// // https://stackoverflow.com/a/51345372/5488616
+// macro_rules! unwrap_or_return {
+//     ( $e:expr ) => {
+//         match $e {
+//             Some(x) => x,
+//             None => return,
+//         }
+//     };
+//     ( $e:expr, $r:expr ) => {
+//         match $e {
+//             Some(x) => x,
+//             None => return $r,
+//         }
+//     };
+// }
+// pub(crate) use unwrap_or_return;