feat: imrpovement and add more methods to Option and Result

src/ro.h

@@ -4,13 +4,14 @@
 #include <stdexcept>
 #include <string>
 #include <memory>
-#include  <functional>
+#include <functional>
+#include <tuple>
 
 #define None(T) (ro::Option<T>())
 #define Some(v) (ro::Option(v))
-#define ERR(fmt,...) Error(ro::sfmt("%s:%d: " fmt, __FILE__, __LINE__, ##__VA_ARGS__))
+#define ERR(fmt, ...) Error(ro::sfmt("%s:%d: " fmt, __FILE__, __LINE__, ##__VA_ARGS__))
-#define Err(e) (ro::Result(e))
+// #define Err(e) (ro::Result(e))
-#define Ok(v) (ro::Result(v))
+// #define Ok(v) (ro::Result(v))
 
 namespace ro
 {
@@ -33,20 +34,21 @@ namespace ro
     public:
         Error(const std::string &s) : runtime_error(s){};
         Error(const char *s) : runtime_error(s){};
-        Error(): runtime_error(""){};
+        Error() : runtime_error(""){};
 
-        inline friend bool operator==(const Error& l, const Error& r)
+        inline friend bool operator==(const Error &l, const Error &r)
         {
             return std::string(l.what()) == std::string(r.what());
         }
 
-        inline Error operator+(const Error& other)
+        inline Error operator+(const Error &other)
         {
             return Error(std::string(this->what()) + "\n" + other.what());
         }
     };
 
-    template <typename T, typename E> class Result;
+    template <typename T, typename E>
+    class Result;
 
     template <typename T>
     class Option
@@ -56,38 +58,94 @@ namespace ro
         Option(T obj) : m_some(obj), m_notnull(true){};
         Option() : m_notnull(false){};
 
-        Option<T>& operator=(const T& value) {insert(value); return *this;};
+        Option<T> &operator=(const T &value)
-        inline friend bool operator==(const Option<T>& l, const Option<T>& r) {
+        {
-            if(!l.m_notnull && !r.m_notnull)
+            insert(value);
+            return *this;
+        };
+        inline friend bool operator==(const Option<T> &l, const Option<T> &r)
+        {
+            if (!l.m_notnull && !r.m_notnull)
             {
                 return true;
             }
-            if(l.m_notnull && r.m_notnull)
+            if (l.m_notnull && r.m_notnull)
             {
                 return l.m_some == r.m_some;
             }
             return false;
         };
 
-        inline bool is_none(){return !m_notnull;};
+        inline friend Option<T> operator|(const Option<T> &l, const Option<T> &r)
-        inline bool is_some(){return m_notnull;};
-        inline T& unwrap()
         {
-            if(m_notnull)
+            if (l.is_some())
+            {
+                return l;
+            }
+            return r;
+        }
+
+        template <typename U>
+        inline friend Option<U> operator&(const Option<T> &l, const Option<U> &r)
+        {
+            if (l.is_some())
+            {
+                return r;
+            }
+            return Option<U>();
+        }
+
+        inline friend Option<T> operator^(const Option<T> &l, const Option<T> &r)
+        {
+            if (l.is_some() != r.is_some())
+            {
+                if (l.is_some())
+                {
+                    return l;
+                }
+                return r;
+            }
+            return Option<T>();
+        }
+
+        inline bool is_none() const { return !m_notnull; };
+        inline bool is_some() const { return m_notnull; };
+        inline const T &unwrap() const
+        {
+            if (m_notnull)
             {
                 return m_some;
             }
             throw Error("Object is None");
         }
-        inline T& get_or_insert(T value)
+
+        inline const T &unwrap_or(const T &alt) const
         {
-            if(!m_notnull)
+            if (m_notnull)
+            {
+                return m_some;
+            }
+            return alt;
+        }
+
+        inline T unwrap_or_else(const std::function<T()> &fn) const
+        {
+            if (m_notnull)
+            {
+                return m_some;
+            }
+            return fn();
+        }
+
+        inline const T &get_or_insert(const T &value)
+        {
+            if (!m_notnull)
             {
                 insert(value);
             }
             return m_some;
         }
-        inline T& insert(T value)
+        inline const T &insert(const T &value)
         {
             m_some = value;
             m_notnull = true;
@@ -95,35 +153,92 @@ namespace ro
         }
 
         template <typename E>
-        inline Result<T, E> ok_or(E err)
+        inline Result<T, E> ok_or(const E &err)
         {
-            if(m_notnull)
+            if (m_notnull)
             {
                 return Result<T, E>(m_some);
             }
             return Result<T, E>(err);
         }
 
-        template<typename U>
+        template <typename U>
-        inline Option<U> map(const std::function<U(T)>& fn)
+        inline Option<U> and_then(const std::function<Option<U>(const T &)> &fn)
         {
-            if(is_some())
+            if (m_notnull)
             {
                 return fn(m_some);
             }
             return Option<U>();
         }
 
-        template<typename U>
+        inline Option<T> or_else(const std::function<Option<T>()> &fn)
-        inline U map_or(U defv, const std::function<U(T)>& fn)
         {
-            if(is_some())
+            if (m_notnull)
+            {
+                return *this;
+            }
+            return fn();
+        }
+
+        template <typename U>
+        inline Option<U> map(const std::function<U(const T &)> &fn)
+        {
+            if (is_some())
+            {
+                return fn(m_some);
+            }
+            return Option<U>();
+        }
+
+        template <typename U>
+        inline U map_or(const U &defv, const std::function<U(const T &)> &fn)
+        {
+            if (is_some())
             {
                 return fn(m_some);
             }
             return defv;
         }
 
+        inline Option<T> filter(const std::function<bool(const T &)> &fn)
+        {
+            if (is_some() && fn(m_some))
+            {
+                return Option<T>(m_some);
+            }
+            return Option<T>();
+        }
+
+        inline Option<T> take()
+        {
+            if (m_notnull)
+            {
+                m_notnull = false;
+                return Option<T>(m_some);
+            }
+            return Option<T>();
+        }
+
+        inline Option<T> take_if(const std::function<bool(const T &)> &fn)
+        {
+            if (m_notnull && fn(m_some))
+            {
+                return take();
+            }
+            return Option<T>();
+        }
+
+        template <typename U>
+        inline Option<std::tuple<T, U>> zip(const Option<U> &other)
+        {
+            if (m_notnull && other.is_some())
+            {
+                return Option<std::tuple<T, U>>(std::tuple<T, U>(m_some, other.unwrap()));
+            }
+            return Option<std::tuple<T, U>>();
+        }
+
     private:
         T m_some;
         bool m_notnull;
@@ -134,66 +249,172 @@ namespace ro
     {
 
     public:
-        Result(T obj) : m_result(obj) {};
+        Result(T obj) : m_result(obj){};
         Result(E err) { m_error.insert(err); };
         Result(){};
 
-        inline Result<T,E>& operator=(const T& value) {m_result = value; m_error = None(E); return *this;};
+        inline Result<T, E> &operator=(const T &value)
-        inline Result<T,E>& operator=(const E& err) {m_error.insert(err); return *this;};
-
-        inline bool is_ok(){return m_error.is_none();};
-        inline bool is_err(){return m_error.is_some();};
-
-        inline T& unwrap()
         {
-            if(is_ok())
+            m_result = value;
+            m_error = None(E);
+            return *this;
+        };
+        inline Result<T, E> &operator=(const E &err)
+        {
+            m_error.insert(err);
+            return *this;
+        };
+
+        inline friend bool operator==(const Result<T, E> &l, const Result<T, E> &r)
+        {
+            if (l.is_ok() != r.is_ok())
+            {
+                return false;
+            }
+            if (l.is_ok())
+            {
+                return l.m_result == r.m_result;
+            }
+            return l.m_error == r.m_error;
+        };
+
+        inline friend bool operator==(const Result<T, E> &l, const E &r)
+        {
+            if (l.is_ok())
+            {
+                return false;
+            }
+            return l.m_error == r;
+        };
+
+        inline friend bool operator==(const Result<T, E> &l, const T &r)
+        {
+            if (l.is_err())
+            {
+                return false;
+            }
+            return l.m_result == r;
+        };
+
+        inline friend Result<T, E> operator|(const Result<T, E> &l, const Result<T, E> &r)
+        {
+            if (l.is_ok())
+            {
+                return l;
+            }
+            return r;
+        }
+
+        template <typename U>
+        inline friend Result<U, E> operator&(const Result<T, E> &l, const Result<U, E> &r)
+        {
+            if (l.is_ok())
+            {
+                return r;
+            }
+            return Result<U, E>(l.m_error.unwrap());
+        }
+
+        inline bool is_ok() const { return m_error.is_none(); };
+        inline bool is_err() const { return m_error.is_some(); };
+
+        template <typename F>
+        inline Result<T, F> or_else(const std::function<Result<T, F>(const E &)> &fn)
+        {
+            if (is_ok())
+            {
+                return Result<T, F>(m_result);
+            }
+            return fn(m_error.unwrap());
+        }
+
+        inline const T &unwrap() const
+        {
+            if (is_ok())
             {
                 return m_result;
             }
             throw m_error.unwrap();
         }
 
-        inline T& expect(E e)
+        inline const E &unwrap_err() const
         {
-            if(is_ok())
+            if (is_err())
+            {
+                return m_error.unwrap();
+            }
+            throw m_result;
+        }
+
+        inline const T &expect(E e) const
+        {
+            if (is_ok())
             {
                 return m_result;
             }
             throw e + m_error.unwrap();
         }
 
-        template<typename U>
+        template <typename U>
-        inline Result<U,E> map(const std::function<U(T)>& fn)
+        inline Result<U, E> map(const std::function<U(const T &)> &fn)
         {
-            if(is_ok())
+            if (is_ok())
             {
                 return fn(m_result);
             }
             return m_error.unwrap();
         }
 
-        template<typename E1>
+        template <typename E1>
-        inline Result<T,E1> map_err(const std::function<E1(E)>& fn)
+        inline Result<T, E1> map_err(const std::function<E1(const E &)> &fn)
         {
-            if(!is_ok())
+            if (!is_ok())
             {
                 return fn(m_error.unwrap());
             }
             return m_result;
         }
 
-        template<typename U>
+        template <typename U>
-        inline U map_or(U defv, const std::function<U(T)>& fn)
+        inline U map_or(const U &defv, const std::function<U(const T &)> &fn)
         {
-            if(is_ok())
+            if (is_ok())
             {
                 return fn(m_result);
             }
             return defv;
         }
 
-        Option<E> err() { return m_error; }
+        template <typename U>
-        Option<T> ok() { return is_ok()?Option<T>(m_result): Option<T>(); }
+        inline Result<U, E> and_then(const std::function<Result<U, E>(const T &)> &fn)
+        {
+            if (is_ok())
+            {
+                return fn(m_result);
+            }
+            return Result<U, E>(m_error.unwrap());
+        }
+
+        inline const T &unwrap_or(const T &alt) const
+        {
+            if (is_ok())
+            {
+                return m_result;
+            }
+            return alt;
+        }
+
+        inline T unwrap_or_else(const std::function<T(const E &)> &fn)
+        {
+            if (is_ok())
+            {
+                return m_result;
+            }
+            return fn(m_error.unwrap());
+        }
+
+        inline const Option<E> &err() const { return m_error; }
+        inline Option<T> ok() const { return is_ok() ? Option<T>(m_result) : Option<T>(); }
 
     private:
         T m_result;

test/test.cpp

@@ -2,12 +2,19 @@
 #include "../src/ro.h"
 #include  <functional>
 #include <iostream>
-
+#include <cstring>
 
 
 using namespace std;
 using namespace ro;
 
+struct Stat{
+    int passed;
+    int total;
+};
+
+static Stat g_stat = {0,0};
+
 #define assert(v,fmt,...) if(!(v)) { \
     throw Error(ro::sfmt("ASSERT ERROR %s:%d: " fmt, __FILE__, __LINE__, ##__VA_ARGS__)); \
 }
@@ -19,12 +26,14 @@ void test(const char* desc, const std::function<void()>& lambda)
     try {
         lambda();
         std::cout << "OK" << std::endl;
+        g_stat.passed++;
     }
     catch(ro::Error e)
     {
         std::cout << "FAILED" << std::endl;
         std::cout << e.what() << std::endl;
     }
+    g_stat.total++;
 }
 
 int main(int argc, char const *argv[])
@@ -52,6 +61,14 @@ int main(int argc, char const *argv[])
         assert(ret.unwrap() == "abc", "Data mistmatch"); 
     });
 
+    test("OPtion get_or_insert", [](){
+        auto x = None(int);
+        int y = x.get_or_insert(5);
+        assert(y == 5, "Unexpected value");
+
+        assert(x == 5, "Unexpected value");
+    });
+
     test("Option map", [](){
         auto fn = [](int x){
             return "Hello";
@@ -67,7 +84,7 @@ int main(int argc, char const *argv[])
     });
 
 
-    test("Option map or", [](){
+    test("Option map_or", [](){
         auto fn = [](int x){
             return ++x;
         };
@@ -81,6 +98,140 @@ int main(int argc, char const *argv[])
         assert(v == 3, "Value mismatch %d",v);
     });
 
+    test("Option filter", [](){
+        auto fn = [](int n) {
+            return n % 2 == 0;
+        };
+        //Option<int> opt = None(int).filter(fn);
+        assert(None(int).filter(fn).is_none(), "Filter value shall be None");
+        assert(Some(3).filter(fn).is_none(), "Filter value shall be None");
+        assert(Some(4).filter(fn).is_some(), "Filter value shall not be None");
+    });
+
+    test("Option OR", [](){
+        auto x = Some(2);
+        auto y = None(int);
+        assert((x | y) == Some(2), "Unexpected value");
+
+        x = None(int);
+        y = Some(100);
+        assert((x | y) == Some(100), "Unexpected value");
+
+        x = Some(2);
+        y = Some(100);
+        assert((x|y) == Some(2), "Unexpected value");
+
+        x = None(int);
+        y = None(int);
+        assert((x | y) == None(int), "Unexpected value");
+    });
+
+    test("Option AND", [](){
+        auto x = Some(2);
+        auto y = None(int);
+        assert((x & y) == None(int), "Unexpected value");
+
+        x = None(int);
+        y = Some(100);
+        assert((x & y) == None(int), "Unexpected value");
+
+        x = Some(2);
+        y = Some(100);
+        assert((x&y) == Some(100), "Unexpected value");
+
+        x = None(int);
+        y = None(int);
+        assert((x & y) == None(int), "Unexpected value");
+    });
+
+    test("Option XOR", [](){
+        auto x = Some(2);
+        auto y = None(int);
+        assert((x ^ y) == Some(2), "Unexpected value");
+
+        x = None(int);
+        y = Some(100);
+        assert((x ^ y) == Some(100), "Unexpected value");
+
+        x = Some(2);
+        y = Some(100);
+        assert((x^y) == None(int), "Unexpected value");
+
+        x = None(int);
+        y = None(int);
+        assert((x ^ y) == None(int), "Unexpected value");
+    });
+
+    test("Option or_else", [](){
+        auto nobody = [](){return None(int);};
+        auto vikings = [](){return Some(100);};
+
+        assert(None(int).or_else(vikings) == Some(100), "Unexpected value");
+        assert(None(int).or_else(nobody) == None(int), "Unexpected value");
+        
+        assert(Some(2).or_else(vikings) == Some(2), "Unexpected value");
+    });
+
+    test("Option and_then", [](){
+        auto fn = [](int x){return string("Hello");};
+
+        assert(Some(1).and_then<string>(fn) == Some(string("Hello")), "Unexpected value");
+        assert(None(int).and_then<string>(fn) == None(string), "Unexpected value");
+    });
+
+    test("Option take", [](){
+        auto x = Some(2);
+        auto y = x.take();
+
+        assert(x == None(int), "Unexpected value");
+        assert(y == Some(2), "Unexpected value");
+        
+        auto z = None(int);
+        y = z.take();
+        assert(x == None(int), "Unexpected value");
+        assert(y == None(int), "Unexpected value");
+    });
+
+    test("Option take_if", [](){
+        auto fn = [](int n) {
+            return n % 2 == 0;
+        };
+        auto x = Some(2);
+        auto y = x.take_if(fn);
+
+        assert(x == None(int), "Unexpected value");
+        assert(y == Some(2), "Unexpected value");
+        
+        auto z = Some(3);
+        y = z.take_if(fn);
+        assert(z == Some(3), "Unexpected value");
+        assert(y == None(int), "Unexpected value");
+    });
+
+    test("Option unwrap_or", [](){
+        assert(Some(2).unwrap_or(4) == 2, "Unexpected value");
+        assert(None(int).unwrap_or(4) == 4, "Unexpected value");
+
+        assert(None(Error).unwrap_or(Error("Hello")) == Error("Hello"), "Unexpected value");
+        
+    });
+    test("Option unwrap_or_else", [](){
+        assert(Some(2).unwrap_or_else([](){ return 4; }) == 2, "Unexpected value");
+        assert(None(int).unwrap_or_else([](){ return 4; }) == 4, "Unexpected value");
+        
+    });
+
+    test("Option zip", [](){
+        auto x = Some(2);
+        auto y = Some(string("Hello"));
+        auto z = None(int);
+
+        assert(x.zip(y).unwrap() == std::tuple(2, string("Hello")), "Unexpected value");
+
+        assert(x.zip(z).is_none(), "Unexpected value");
+        
+    });
+
     test("Test Result", []{
         Result<string, Error> ret = ERR("Error");
         assert(ret.is_err(), "Object should containe error object");
@@ -132,7 +283,7 @@ int main(int argc, char const *argv[])
     });
 
 
-    test("Result map err", [](){
+    test("Result map_err", [](){
         auto fn = [](int x){
             return "Hello";
         };
@@ -145,7 +296,7 @@ int main(int argc, char const *argv[])
         assert(ret1.err().unwrap() == "Hello", "Value mistmatch");
     });
 
-     test("Result map or", [](){
+     test("Result map_or", [](){
         auto fn = [](int x){
             return ++x;
         };
@@ -159,4 +310,91 @@ int main(int argc, char const *argv[])
         assert(v == 3, "Value mismatch %d",v);
     });
 
+    test("Result AND", [](){
+        Result<int, Error> x = 2;
+        Result<int, Error> y = Error("Hello");
+        assert((x&y) == Error("Hello"), "Value mismatch");
+
+        x = Error("Error1");
+        y = 10;
+        assert((x&y) == Error("Error1"), "Value mismatch");
+
+        x = Error("Error1");
+        y = Error("Error2");
+        assert((x&y) == Error("Error1"), "Value mismatch");
+
+        x = 1;
+        y = 10;
+        assert((x&y) == 10, "Value mismatch");
+    });
+
+    test("Result OR", [](){
+        Result<int, Error> x = 2;
+        Result<int, Error> y = Error("Hello");
+        assert((x|y) == 2, "Value mismatch");
+
+        x = Error("Error1");
+        y = 10;
+        assert((x|y) == 10, "Value mismatch");
+
+        x = Error("Error1");
+        y = Error("Error2");
+        assert((x|y) == Error("Error2"), "Value mismatch");
+
+        x = 1;
+        y = 10;
+        assert((x|y) == 1, "Value mismatch");
+    });
+
+    test("Result and_then", [](){
+        auto fn = [](int x){return string("Hello");};
+
+         Result<int, Error> x = 2;
+         auto test = Result<string,Error>(string("Hello"));
+        assert(x.and_then<string>(fn) == string("Hello"), "Unexpected value");
+        x = Error("Error");
+        assert(x.and_then<string>(fn) == Error("Error"), "Unexpected value");
+    });
+
+    test("Result or_else", [](){
+        auto sq = [](int x){return x*x;};
+        auto err = [](int x){return x;};
+        Result<double, int> x(2.0);
+        auto ret = x.or_else<int>(sq).or_else<int>(sq);
+        assert(ret == 2.0, "Unexpected value");
+        ret = x.or_else<int>(err).or_else<int>(sq);
+        assert(ret == 2.0, "Unexpected value");
+
+        x = 3;
+        ret = x.or_else<int>(sq).or_else<int>(err);
+        assert(ret == 9, "Unexpected value");
+
+        ret = x.or_else<int>(err).or_else<int>(err);
+        assert(ret == 3, "Unexpected value");
+    });
+
+    test("Result unwrap_err", [](){
+        Result<int, Error> x = Error("Hello");
+        assert(x.unwrap_err() == Error("Hello"), "Unexpected value");
+    });
+
+    test("Result unwrap_or", [](){
+        Result<int, Error> x = 2;
+        assert(x.unwrap_or(10) == 2, "Unexpected value");
+
+        x = ERR("Error");
+        assert(x.unwrap_or(10) == 10, "Unexpected value");
+    });
+
+    test("Result unwrap_or_else", [](){
+        auto fn = [](const Error& x){return strlen(x.what());};
+        Result<int, Error> x = 2;
+        assert(x.unwrap_or_else(fn) == 2, "Unexpected value");
+
+        x = Error("HELLO");
+        assert(x.unwrap_or_else(fn) == 5, "Unexpected value");
+    });
+
+
+    cout << "REPORT: " << g_stat.passed << " tests passed / " << g_stat.total << " tests." << endl;
 }