diff --git a/CMakeLists.txt b/CMakeLists.txt
index 20c84a0..e437735 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,7 +1,7 @@
-cmake_minimum_required(VERSION 3.5)
+cmake_minimum_required(VERSION 3.20)
 include(cmake/color.cmake)
 
-set(BLT_VERSION 0.16.5)
+set(BLT_VERSION 0.16.6)
 set(BLT_TEST_VERSION 0.0.1)
 
 set(BLT_TARGET BLT)
diff --git a/include/blt/std/string.h b/include/blt/std/string.h
index 43ea9c9..25e688a 100644
--- a/include/blt/std/string.h
+++ b/include/blt/std/string.h
@@ -91,22 +91,7 @@ namespace blt::string
 #endif
     }
     
-    static inline BLT_CPP20_CONSTEXPR bool ends_with(std::string_view string, std::string_view search)
-    {
-#ifdef BLT_USE_CPP20
-        return string.ends_with(search);
-#else
-        if (search.length() > string.length())
-            return false;
-        auto startPosition = string.length() - search.length();
-        for (unsigned int i = 0; i < search.length(); i++)
-        {
-            if (string[startPosition + i] != search[i])
-                return false;
-        }
-        return true;
-#endif
-    }
+    static inline BLT_CPP20_CONSTEXPR bool ends_with(std::string_view string, std::string_view search);
     
     static inline BLT_CPP20_CONSTEXPR bool ends_with(std::string_view string, char search)
     {
@@ -119,166 +104,38 @@ namespace blt::string
 #endif
     }
     
-    static inline std::optional<std::vector<size_t>> containsAll(std::string_view string, const std::unordered_set<char>& search)
-    {
-        std::vector<size_t> pos;
-        for (size_t i = 0; i < string.length(); i++)
-        {
-            if (BLT_CONTAINS(search, string[i]))
-                pos.push_back(i);
-        }
-        if (!pos.empty())
-            return pos;
-        return {};
-    }
+    std::optional<std::vector<size_t>> containsAll(std::string_view string, const std::unordered_set<char>& search);
     
-    static inline size_t contains(std::string_view string, const std::unordered_set<char>& search)
-    {
-        for (size_t i = 0; i < string.length(); i++)
-        {
-            if (BLT_CONTAINS(search, string[i]))
-                return i;
-        }
-        return false;
-    }
+    size_t contains(std::string_view string, const std::unordered_set<char>& search);
     
-    static inline BLT_CPP20_CONSTEXPR bool contains(std::string_view string, const char search)
-    {
-#if __cplusplus >= 202002L
-        return std::ranges::any_of(string, [search](const char c) -> bool {
-            return c == search;
-        });
-#else
-        for (const char c : string)
-        {
-            if (c == search)
-                return true;
-        }
-        return false;
-#endif
-    }
     
-    static inline BLT_CPP20_CONSTEXPR bool contains(std::string_view string, std::string_view search)
-    {
-        if (search.length() > string.length())
-            return false;
-        for (unsigned int i = 0; i < string.length(); i++)
-        {
-            if (string[i] == search[0])
-            {
-                bool correct = true;
-                for (unsigned int j = 0; j < search.length(); j++)
-                {
-                    if (string[i + j] != search[j])
-                    {
-                        correct = false;
-                        break;
-                    }
-                }
-                if (correct)
-                    return true;
-            }
-        }
-        return false;
-    }
+    BLT_CPP20_CONSTEXPR bool contains(std::string_view string, char search);
+    
+    BLT_CPP20_CONSTEXPR bool contains(std::string_view string, std::string_view search);
     
     /**
      * Converts the string into lower case
      * @param s string to lower case
      * @return a string copy that is all lower case
      */
-    static inline BLT_CPP20_CONSTEXPR std::string toLowerCase(std::string_view s)
-    {
-        std::string str;
-        std::for_each(
-                s.begin(), s.end(), [&str](unsigned char ch) {
-                    str += (char) std::tolower(ch);
-                }
-        );
-        return str;
-    }
+    BLT_CPP20_CONSTEXPR std::string toLowerCase(std::string_view s);
     
     /**
      * Converts the string into upper case
      * @param s string to upper case
      * @return a string copy that is all upper case
      */
-    static inline BLT_CPP20_CONSTEXPR std::string toUpperCase(std::string_view s)
-    {
-        std::string str;
-        std::for_each(
-                s.begin(), s.end(), [&str](unsigned char ch) {
-                    str += (char) std::toupper(ch);
-                }
-        );
-        return str;
-    }
+    BLT_CPP20_CONSTEXPR std::string toUpperCase(std::string_view s);
     
     // taken from https://stackoverflow.com/questions/14265581/parse-split-a-string-in-c-using-string-delimiter-standard-c
     // extended to return a vector
-    static inline BLT_CPP20_CONSTEXPR std::vector<std::string> split(std::string_view s, std::string_view delim)
-    {
-        size_t pos = 0;
-        size_t from = 0;
-        std::vector<std::string> tokens;
-        while ((pos = s.find(delim, from)) != std::string::npos)
-        {
-            auto size = pos - from;
-            auto token = s.substr(from, size);
-            tokens.emplace_back(token);
-            from += size + delim.length();
-        }
-        tokens.emplace_back(s.substr(from));
-        return tokens;
-    }
-
-    static inline BLT_CPP20_CONSTEXPR std::vector<std::string> split(std::string_view s, char delim)
-    {
-        size_t pos = 0;
-        size_t from = 0;
-        std::vector<std::string> tokens;
-        while ((pos = s.find(delim, from)) != std::string::npos)
-        {
-            auto size = pos - from;
-            auto token = s.substr(from, size);
-            tokens.emplace_back(token);
-            from += size + 1;
-        }
-        tokens.emplace_back(s.substr(from));
-        return tokens;
-    }
+    BLT_CPP20_CONSTEXPR std::vector<std::string> split(std::string_view s, std::string_view delim);
     
-    static inline BLT_CPP20_CONSTEXPR std::vector<std::string_view> split_sv(std::string_view s, std::string_view delim)
-    {
-        size_t pos = 0;
-        size_t from = 0;
-        std::vector<std::string_view> tokens;
-        while ((pos = s.find(delim, from)) != std::string::npos)
-        {
-            auto size = pos - from;
-            auto token = s.substr(from, size);
-            tokens.push_back(token);
-            from += size + delim.length();
-        }
-        tokens.push_back(s.substr(from));
-        return tokens;
-    }
+    BLT_CPP20_CONSTEXPR std::vector<std::string> split(std::string_view s, char delim);
     
-    static inline BLT_CPP20_CONSTEXPR std::vector<std::string_view> split_sv(std::string_view s, char delim)
-    {
-        size_t pos = 0;
-        size_t from = 0;
-        std::vector<std::string_view> tokens;
-        while ((pos = s.find(delim, from)) != std::string::npos)
-        {
-            auto size = pos - from;
-            auto token = s.substr(from, size);
-            tokens.push_back(token);
-            from += size + 1;
-        }
-        tokens.push_back(s.substr(from));
-        return tokens;
-    }
+    BLT_CPP20_CONSTEXPR std::vector<std::string_view> split_sv(std::string_view s, std::string_view delim);
+    
+    BLT_CPP20_CONSTEXPR std::vector<std::string_view> split_sv(std::string_view s, char delim);
     
     // https://stackoverflow.com/questions/3418231/replace-part-of-a-string-with-another-string
     static inline BLT_CPP20_CONSTEXPR bool replace(std::string& str, std::string_view from, std::string_view to)
@@ -290,17 +147,7 @@ namespace blt::string
         return true;
     }
     
-    static inline BLT_CPP20_CONSTEXPR void replaceAll(std::string& str, std::string_view from, std::string_view to)
-    {
-        if (from.empty())
-            return;
-        size_t start_pos = 0;
-        while ((start_pos = str.find(from, start_pos)) != std::string::npos)
-        {
-            str.replace(start_pos, from.length(), to);
-            start_pos += to.length(); // In case 'to' contains 'from', like replacing 'x' with 'yx'
-        }
-    }
+    BLT_CPP20_CONSTEXPR void replaceAll(std::string& str, std::string_view from, std::string_view to);
     
     // taken from https://stackoverflow.com/questions/216823/how-to-trim-an-stdstring
     // would've preferred to use boost lib but instructions said to avoid external libs
@@ -396,6 +243,14 @@ namespace blt::string
 #endif
     }
     
+    class match
+    {
+        private:
+        
+        public:
+        
+    };
+    
 }
 
 #endif //BLT_STRING_H
diff --git a/libraries/parallel-hashmap b/libraries/parallel-hashmap
index 7ef2e73..67c2461 160000
--- a/libraries/parallel-hashmap
+++ b/libraries/parallel-hashmap
@@ -1 +1 @@
-Subproject commit 7ef2e733416953b222851f9a360d7fc72d068ee5
+Subproject commit 67c24619e4f5ab2097b74cc397732c17a25d6944
diff --git a/src/blt/std/string.cpp b/src/blt/std/string.cpp
index 2ce5dd7..c8c125c 100644
--- a/src/blt/std/string.cpp
+++ b/src/blt/std/string.cpp
@@ -3,27 +3,199 @@
 //
 #include <blt/std/string.h>
 
-void blt::string::StringBuffer::expand() {
-    size_t multiplier = size / BLOCK_SIZE;
-    auto newSize = BLOCK_SIZE * (multiplier * 2);
-    characterBuffer = static_cast<char*>(realloc(characterBuffer, newSize));
-    size = newSize;
-}
-
-void blt::string::StringBuffer::trim() {
-    characterBuffer = static_cast<char*>(realloc(characterBuffer, front+1));
-    size = front+1;
-    characterBuffer[front] = '\0';
-}
-
-blt::string::StringBuffer& blt::string::StringBuffer::operator<<(char c) {
-    characterBuffer[front++] = c;
-    if (front > size)
-        expand();
-    return *this;
-}
-
-std::string blt::string::StringBuffer::str() {
-    trim();
-    return std::string{characterBuffer};
+namespace blt
+{
+    
+    void blt::string::StringBuffer::expand()
+    {
+        size_t multiplier = size / BLOCK_SIZE;
+        auto newSize = BLOCK_SIZE * (multiplier * 2);
+        characterBuffer = static_cast<char*>(realloc(characterBuffer, newSize));
+        size = newSize;
+    }
+    
+    void blt::string::StringBuffer::trim()
+    {
+        characterBuffer = static_cast<char*>(realloc(characterBuffer, front + 1));
+        size = front + 1;
+        characterBuffer[front] = '\0';
+    }
+    
+    blt::string::StringBuffer& blt::string::StringBuffer::operator<<(char c)
+    {
+        characterBuffer[front++] = c;
+        if (front > size)
+            expand();
+        return *this;
+    }
+    
+    std::string blt::string::StringBuffer::str()
+    {
+        trim();
+        return std::string{characterBuffer};
+    }
+    
+    
+    bool string::contains(std::string_view string, std::string_view search)
+    {
+        if (search.length() > string.length())
+            return false;
+        for (unsigned int i = 0; i < string.length(); i++)
+        {
+            if (string[i] == search[0])
+            {
+                bool correct = true;
+                for (unsigned int j = 0; j < search.length(); j++)
+                {
+                    if (string[i + j] != search[j])
+                    {
+                        correct = false;
+                        break;
+                    }
+                }
+                if (correct)
+                    return true;
+            }
+        }
+        return false;
+    }
+    
+    std::string string::toLowerCase(std::string_view s)
+    {
+        std::string str;
+        std::for_each(
+                s.begin(), s.end(), [&str](unsigned char ch) {
+                    str += (char) std::tolower(ch);
+                }
+        );
+        return str;
+    }
+    
+    bool string::contains(std::string_view string, const char search)
+    {
+#if __cplusplus >= 202002L
+        return std::ranges::any_of(string, [search](const char c) -> bool {
+            return c == search;
+        });
+#else
+        for (const char c : string)
+        {
+            if (c == search)
+                return true;
+        }
+        return false;
+#endif
+    }
+    
+    size_t string::contains(std::string_view string, const std::unordered_set<char>& search)
+    {
+        for (size_t i = 0; i < string.length(); i++)
+        {
+            if (BLT_CONTAINS(search, string[i]))
+                return i;
+        }
+        return false;
+    }
+    
+    std::optional<std::vector<size_t>> string::containsAll(std::string_view string, const std::unordered_set<char>& search)
+    {
+        std::vector<size_t> pos;
+        for (size_t i = 0; i < string.length(); i++)
+        {
+            if (BLT_CONTAINS(search, string[i]))
+                pos.push_back(i);
+        }
+        if (!pos.empty())
+            return pos;
+        return {};
+    }
+    
+    std::string string::toUpperCase(std::string_view s)
+    {
+        std::string str;
+        std::for_each(
+                s.begin(), s.end(), [&str](unsigned char ch) {
+                    str += (char) std::toupper(ch);
+                }
+        );
+        return str;
+    }
+    
+    std::vector<std::string> string::split(std::string_view s, std::string_view delim)
+    {
+        size_t pos = 0;
+        size_t from = 0;
+        std::vector<std::string> tokens;
+        while ((pos = s.find(delim, from)) != std::string::npos)
+        {
+            auto size = pos - from;
+            auto token = s.substr(from, size);
+            tokens.emplace_back(token);
+            from += size + delim.length();
+        }
+        tokens.emplace_back(s.substr(from));
+        return tokens;
+    }
+    
+    std::vector<std::string> string::split(std::string_view s, char delim)
+    {
+        size_t pos = 0;
+        size_t from = 0;
+        std::vector<std::string> tokens;
+        while ((pos = s.find(delim, from)) != std::string::npos)
+        {
+            auto size = pos - from;
+            auto token = s.substr(from, size);
+            tokens.emplace_back(token);
+            from += size + 1;
+        }
+        tokens.emplace_back(s.substr(from));
+        return tokens;
+    }
+    
+    std::vector<std::string_view> string::split_sv(std::string_view s, std::string_view delim)
+    {
+        size_t pos = 0;
+        size_t from = 0;
+        std::vector<std::string_view> tokens;
+        while ((pos = s.find(delim, from)) != std::string::npos)
+        {
+            auto size = pos - from;
+            auto token = s.substr(from, size);
+            tokens.push_back(token);
+            from += size + delim.length();
+        }
+        tokens.push_back(s.substr(from));
+        return tokens;
+    }
+    
+    std::vector<std::string_view> string::split_sv(std::string_view s, char delim)
+    {
+        size_t pos = 0;
+        size_t from = 0;
+        std::vector<std::string_view> tokens;
+        while ((pos = s.find(delim, from)) != std::string::npos)
+        {
+            auto size = pos - from;
+            auto token = s.substr(from, size);
+            tokens.push_back(token);
+            from += size + 1;
+        }
+        tokens.push_back(s.substr(from));
+        return tokens;
+    }
+    
+    void string::replaceAll(std::string& str, std::string_view from, std::string_view to)
+    {
+        if (from.empty())
+            return;
+        size_t start_pos = 0;
+        while ((start_pos = str.find(from, start_pos)) != std::string::npos)
+        {
+            str.replace(start_pos, from.length(), to);
+            start_pos += to.length(); // In case 'to' contains 'from', like replacing 'x' with 'yx'
+        }
+    }
+    
+    
 }