Merge pull request #17 from pfultz2/if_c

Add if_c
boostorg · Aug 20, 2015 · cd68d74 · cd68d74
2 parents 1d4aa72 + d95064a
commit cd68d74
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Showing 2 changed files with 76 additions and 1 deletion.
diff --git a/fit/if.h b/fit/if.h
@@ -14,21 +14,31 @@
 /// Description
 /// -----------
 /// 
-/// The `if_` function applies a boolen condition to the function.
+/// The `if_` function applies a boolen condition to the function. The `if_c`
+/// version can be used to give a boolean condtion directly(intead of relying
+/// on dependent typing).
 /// 
 /// Synopsis
 /// --------
 /// 
 ///     template<class IntegralConstant>
 ///     constexpr auto if_(IntegralConstant);
 /// 
+///     template<bool B, class F>
+///     constexpr auto if_c(F);
+/// 
 /// Requirements
 /// ------------
 /// 
 /// IntegralConstant must be:
 /// 
 ///     IntegralConstant
 /// 
+/// F must be:
+/// 
+///     FunctionObject
+///     MoveConstructible
+/// 
 /// Example
 /// -------
 /// 
@@ -102,6 +112,12 @@ struct if_f
 
 }
 
+template<bool B, class F>
+constexpr detail::if_adaptor<B, F> if_c(F f)
+{
+    return detail::if_adaptor<B, F>(fit::move(f));
+}
+
 FIT_DECLARE_STATIC_VAR(if_, detail::if_f);
 
 }

diff --git a/test/if.cpp b/test/if.cpp
@@ -59,6 +59,42 @@ FIT_TEST_CASE()
     FIT_STATIC_TEST_CHECK(test_int<is_not_5>()(6.0));
 }
 
+template<class F>
+struct test_int_c
+{
+    template<class T>
+    constexpr bool operator()(T x) const
+    {
+        return fit::conditional(
+            fit::if_c<std::is_integral<T>::value>(F()),
+            fit::always(true)
+        )(x);
+    }
+};
+
+FIT_TEST_CASE()
+{
+    FIT_TEST_CHECK(test_int_c<is_5>()(5));
+    FIT_TEST_CHECK(test_int_c<is_5>()(5L));
+    FIT_TEST_CHECK(test_int_c<is_5>()(5.0));
+    FIT_TEST_CHECK(test_int_c<is_5>()(6.0));
+
+    FIT_TEST_CHECK(test_int_c<is_not_5>()(6));
+    FIT_TEST_CHECK(test_int_c<is_not_5>()(6L));
+    FIT_TEST_CHECK(test_int_c<is_not_5>()(5.0));
+    FIT_TEST_CHECK(test_int_c<is_not_5>()(6.0));
+
+    FIT_STATIC_TEST_CHECK(test_int_c<is_5>()(5));
+    FIT_STATIC_TEST_CHECK(test_int_c<is_5>()(5L));
+    FIT_STATIC_TEST_CHECK(test_int_c<is_5>()(5.0));
+    FIT_STATIC_TEST_CHECK(test_int_c<is_5>()(6.0));
+
+    FIT_STATIC_TEST_CHECK(test_int_c<is_not_5>()(6));
+    FIT_STATIC_TEST_CHECK(test_int_c<is_not_5>()(6L));
+    FIT_STATIC_TEST_CHECK(test_int_c<is_not_5>()(5.0));
+    FIT_STATIC_TEST_CHECK(test_int_c<is_not_5>()(6.0));
+}
+
 struct sum_f
 {
     template<class T>
@@ -82,3 +118,26 @@ FIT_TEST_CASE()
 }
 
 
+struct sum_f_c
+{
+    template<class T>
+    constexpr int operator()(T x, T y) const
+    {
+        return fit::conditional(
+            fit::if_c<std::is_integral<T>::value>(fit::_ + fit::_),
+            fit::always(0)
+        )(x, y);
+    }
+};
+
+FIT_TEST_CASE()
+{
+    FIT_TEST_CHECK(sum_f_c()(1, 2) == 3);
+    FIT_TEST_CHECK(sum_f_c()(1.0, 2.0) == 0);
+    FIT_TEST_CHECK(sum_f_c()("", "") == 0);
+
+    FIT_STATIC_TEST_CHECK(sum_f_c()(1, 2) == 3);
+    FIT_STATIC_TEST_CHECK(sum_f_c()("", "") == 0);
+}
+
+