Changes in src/Common/Iterate.hpp [ee22919:45a091b]

File:

• src/Common/Iterate.hpp (modified) (1 diff)

src/Common/Iterate.hpp

@@ -208 +208 @@
         return group_iterate_t<Args...>( std::forward<Args>( args )... );
 }
+
+// -----------------------------------------------------------------------------
+// Helper struct and function to support
+// for ( val : lazy_map( container1, f ) ) {}
+// syntax to have a for each that iterates a container,
+// mapping each element by applying f.
+
+template< typename T, typename Func >
+struct lambda_iterate_t {
+        const T & ref;
+        std::function<Func> f;
+
+        struct iterator {
+                typedef decltype(begin(ref)) Iter;
+                Iter it;
+                std::function<Func> f;
+                iterator( Iter it, std::function<Func> f ) : it(it), f(f) {}
+                iterator & operator++() {
+                        ++it; return *this;
+                }
+                bool operator!=( const iterator &other ) const { return it != other.it; }
+                auto operator*() const -> decltype(f(*it)) { return f(*it); }
+        };
+
+        lambda_iterate_t( const T & ref, std::function<Func> f ) : ref(ref), f(f) {}
+
+        auto begin() const -> decltype(iterator(std::begin(ref), f)) { return iterator(std::begin(ref), f); }
+        auto end() const   -> decltype(iterator(std::end(ref), f)) { return iterator(std::end(ref), f); }
+};
+
+template< typename... Args >
+lambda_iterate_t<Args...> lazy_map( const Args &... args ) {
+        return lambda_iterate_t<Args...>( args...);
+}
+
+// Local Variables: //
+// tab-width: 4 //
+// mode: c++ //
+// compile-command: "make install" //
+// End: //