feat: enable_if

1 files changed, 22 insertions, 0 deletions

diff --git a/examples/enable_if.sfinae b/examples/enable_if.sfinae
new file mode 100644
index 0000000..ff7dacc
--- /dev/null
+++ b/examples/enable_if.sfinae
@@ -0,0 +1,22 @@
+// ::enable_if_t runs a ::sequence of statements when its condition holds
+// the statements inside are separated by commas and each one is still committed
+
+::enable_if_t<
+    ::is_same<::remove_cv_t<::int32_t>, ::int32_t>::value,
+    ::sequence<
+        ::declare<::name<'x'>, ::decltype(::difference<'C', 'A'>)>::commit,
+        ::emit<::decltype(::value_of<::name<'x'>>)>::commit
+    >
+>::commit;
+
+// this one never runs, so nothing is printed and nothing is asserted
+::enable_if_t<
+    ::false_type::value,
+    ::sequence<
+        ::static_assert<::false_type::value>::commit,
+        ::emit<::decltype(::difference<'Z', 'A'>)>::commit
+    >
+>::commit;
+
+// an empty sequence is allowed, for when you have nothing to say
+::enable_if_t<::true_type::value, ::sequence<>>::commit;