Add lazy_lift.

alialib · Aug 8, 2018 · 8195235 · 8195235
1 parent 8317ece
commit 8195235
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diff --git a/src/alia/signals/application.hpp b/src/alia/signals/application.hpp
@@ -89,6 +89,13 @@ lazy_apply(Function const& f, Arg0 const& arg0, Arg1 const& arg1)
         Arg1>(f, arg0, arg1);
 }
 
+template<class Function>
+auto
+lazy_lift(Function const& f)
+{
+    return [f](auto&&... args) { return lazy_apply(f, args...); };
+}
+
 // alia_method(m) wraps a method name in a lambda so that it can be passed as a
 // function object.
 #define ALIA_METHOD(m) [](auto const& x) { return x.m(); }

diff --git a/unit_tests/signals/application.cpp b/unit_tests/signals/application.cpp
@@ -41,6 +41,18 @@ TEST_CASE("lazy_apply", "[signals]")
     REQUIRE(s3.value_id() != s4.value_id());
 }
 
+TEST_CASE("lazy_lift", "[signals]")
+{
+    auto s = lazy_lift([](int i) { return 2 * i; })(value(1));
+
+    typedef decltype(s) signal_t;
+    REQUIRE(signal_can_read<signal_t>::value);
+    REQUIRE(!signal_can_write<signal_t>::value);
+
+    REQUIRE(signal_is_readable(s));
+    REQUIRE(read_signal(s) == 2);
+}
+
 TEST_CASE("alia_method", "[signals]")
 {
     auto v = value("test text");