Local type resolution added, framework for local use statements

1 files changed, 55 insertions, 0 deletions

diff --git a/src/common.hpp b/src/common.hpp
index a7b14fdd..4e3e9be7 100644
--- a/src/common.hpp
+++ b/src/common.hpp
@@ -8,9 +8,64 @@
 
 #include <iostream>
 #include <vector>
+#include <cassert>
 
 #define DEBUG(ss)   do{ ::std::cerr << __FUNCTION__ << ": " << ss << ::std::endl; } while(0)
 
+namespace rust {
+
+template<typename T>
+class option
+{
+    bool    m_set;
+    T   m_data;
+public:
+    option(T ent):
+        m_set(true),
+        m_data( ::std::move(ent) )
+    {}
+    option():
+        m_set(false)
+    {}
+    
+    bool is_none() const { return !m_set; }
+    bool is_some() const { return m_set; }
+    
+    const T& unwrap() const {
+        assert(is_some());
+        return m_data;
+    }
+};
+template<typename T>
+class option<T&>
+{
+    T* m_ptr;
+public:
+    option(T& ent):
+        m_ptr(&ent)
+    {}
+    option():
+        m_ptr(nullptr)
+    {}
+    
+    bool is_none() const { return m_ptr == nullptr; }
+    bool is_some() const { return m_ptr != nullptr; }
+    T& unwrap() const {
+        assert(is_some());
+        return *m_ptr;
+    }
+};
+template<typename T>
+option<T> Some(T data) {
+    return option<T>( ::std::move(data) );
+}
+template<typename T>
+option<T> None() {
+    return option<T>( );
+}
+
+};
+
 namespace AST {
 
 template <typename T>