[GitHub] [incubator-kvrocks] tisonkun commented on a diff in pull request #644: Refactor Trim/Split/Split2KV functions in util.h

[GitBox <gi...@apache.org>]

tisonkun commented on code in PR #644:
URL: https://github.com/apache/incubator-kvrocks/pull/644#discussion_r902397536


##########
src/util.cc:
##########
@@ -371,7 +371,14 @@ std::string Trim(std::string in, const std::string &chars) {
 std::vector<std::string> Split(const std::string &in, const std::string &delim) {
   std::vector<std::string> out;
 
-  if (in.empty() || delim.empty()) return out;
+  if (in.empty()) {
+    return out;
+  }
+
+  if (delim.empty()) {

Review Comment:
   Sorry. After take a look at Java's `Spring.split` and C++20's [`split_view`](https://en.cppreference.com/w/cpp/ranges/split_view), its seems empty delim will cause output a string vector contains every character as a string member.
   
   ```java
   jshell> "123".split("")
   $1 ==> String[3] { "1", "2", "3" }
   
   jshell> "1 2 3".split("")
   $2 ==> String[5] { "1", " ", "2", " ", "3" }
   ```
   
   ```cpp
   #include <iostream>
   #include <iomanip>
   #include <ranges>
   #include <string_view>
    
   int main() {
       constexpr std::string_view words{"Hello-_-C++-_-20-_-!"};
       constexpr std::string_view delim{""};
       for (const auto word : std::views::split(words, delim)) {
           std::cout << std::quoted(std::string_view(word.begin(), word.end())) << ' ';
       }
   }
   // "H" "e" "l" "l" "o" "-" "_" "-" "C" "+" "+" "-" "_" "-" "2" "0" "-" "_" "-" "!" 
   // https://wandbox.org/permlink/5BZQHqUYd36t0WbQ
   ```



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