feat: add reapts and loops

1 files changed, 23 insertions, 0 deletions

diff --git a/examples/countdown.sfinae b/examples/countdown.sfinae
new file mode 100644
index 0000000..bd7c4a3
--- /dev/null
+++ b/examples/countdown.sfinae
@@ -0,0 +1,23 @@
+// count from 3 down to 1, then make sure we got to 0
+// ::repeat runs its sequence a number of times, and that is the whole loop
+
+::declare<::name<'i'>, ::decltype(::difference<'D', 'A'>)>::commit;
+
+::repeat<
+    ::value_of<::name<'i'>>,
+    ::sequence<
+        ::emit<::decltype(::value_of<::name<'i'>>)>::commit,
+        ::declare<
+            ::name<'n', 'e', 'x', 't'>,
+            ::decltype(::sum<::value_of<::name<'i'>>, ::difference<'A', 'B'>>)
+        >::commit,
+        ::undeclare<::name<'i'>>::commit,
+        ::declare<::name<'i'>, ::decltype(::value_of<::name<'n', 'e', 'x', 't'>>)>::commit,
+        ::undeclare<::name<'n', 'e', 'x', 't'>>::commit
+    >
+>::commit;
+
+::static_assert<::equal<::value_of<::name<'i'>>, ::difference<'A', 'A'>>::value>::commit;
+
+// a negative count runs nothing, which is the only sensible thing it could do
+::repeat<::difference<'A', 'D'>, ::sequence<::static_assert<::false_type::value>::commit>>::commit;