From b8ac4c450c5994971ee415c9a1e9494785786e2e Mon Sep 17 00:00:00 2001
From: Dany LE <dany-externe.le@edf.fr>
Date: Wed, 28 Feb 2024 17:32:16 +0100
Subject: [PATCH] feat: add into method to Option and Result + macro try_unwrap

---
 src/ro.h      | 21 +++++++++++++++++++++
 test/test.cpp | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+)

diff --git a/src/ro.h b/src/ro.h
index 587299a..1882f4c 100644
--- a/src/ro.h
+++ b/src/ro.h
@@ -10,6 +10,7 @@
 #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 try_unwrap(l,...) try{l=(__VA_ARGS__).unwrap();}catch(ro::Error e){return e;}
 // #define Err(e) (ro::Result(e))
 // #define Ok(v) (ro::Result(v))
 
@@ -181,6 +182,16 @@ namespace ro
             return fn();
         }
 
+        inline bool into(T &output) const
+        {
+            if(is_some())
+            {
+                output = m_some;
+                return true;
+            }
+            return false;
+        }
+
         template <typename U>
         inline Option<U> map(const std::function<U(const T &)> &fn)
         {
@@ -404,6 +415,16 @@ namespace ro
             return alt;
         }
 
+        inline bool into(T &output) const
+        {
+            if(is_ok())
+            {
+                output = m_result;
+                return true;
+            }
+            return false;
+        }
+
         inline T unwrap_or_else(const std::function<T(const E &)> &fn)
         {
             if (is_ok())
diff --git a/test/test.cpp b/test/test.cpp
index 37394a1..5646f69 100644
--- a/test/test.cpp
+++ b/test/test.cpp
@@ -19,6 +19,10 @@ static Stat g_stat = {0,0};
     throw Error(ro::sfmt("ASSERT ERROR %s:%d: " fmt, __FILE__, __LINE__, ##__VA_ARGS__)); \
 }
 
+class TestError: public Error {
+public:
+    TestError(const char *s) : Error(s){};
+};
 
 void test(const char* desc, const std::function<void()>& lambda)
 {
@@ -36,6 +40,13 @@ void test(const char* desc, const std::function<void()>& lambda)
     g_stat.total++;
 }
 
+Result<int, Error> test_macro(const Result<int, Error> & target)
+{
+    int a;
+    try_unwrap(a,target);
+    return a;
+}
+
 int main(int argc, char const *argv[])
 {
     test("Test Option", [](){
@@ -231,6 +242,20 @@ int main(int argc, char const *argv[])
         assert(x.zip(z).is_none(), "Unexpected value");
         
     });
+    
+    test("Option Into", [](){
+        Option<int> x = 2;
+        int y = 0;
+        bool v = x.into(y);
+        assert(v, "Return value shall be true");
+        assert(y == 2, "Unexpected value");
+
+        x = None(int);
+        v = x.into(y);
+        y = 0;
+        assert(v == false, "Return value shall not be true");
+        assert(y == 0, "Unexpected value");
+    });
 
     test("Test Result", []{
         Result<string, Error> ret = ERR("Error");
@@ -263,6 +288,7 @@ int main(int argc, char const *argv[])
         catch(Error e)
         {
             assert(true, "%s", e.what());
+            cout << e.what() << endl;
         }
     });
 
@@ -396,5 +422,27 @@ int main(int argc, char const *argv[])
     });
 
 
+    test("Result Into", [](){
+        Result<int, Error> x = 2;
+        int y = 0;
+        bool v = x.into(y);
+        assert(v, "Return value shall be true");
+        assert(y == 2, "Unexpected value");
+
+        x = ERR("Error");
+        v = x.into(y);
+        y = 0;
+        assert(v == false, "Return value shall not be true");
+        assert(y == 0, "Unexpected value");
+    });
+
+    test("try_unwrap", [](){
+        Result<int, Error> x = test_macro(Result<int, Error>(10));
+        assert(x == 10, "Unexpected value");
+
+        x = test_macro(Result<int, Error>(Error("Hello")));
+        assert(x.is_err(), "Unexpected value");
+    });
+
     cout << "REPORT: " << g_stat.passed << " tests passed / " << g_stat.total << " tests." << endl;
 }