feat: add conditionals

1 files changed, 35 insertions, 0 deletions

diff --git a/examples/conditions.sfinae b/examples/conditions.sfinae
new file mode 100644
index 0000000..e930480
--- /dev/null
+++ b/examples/conditions.sfinae
@@ -0,0 +1,35 @@
+// a condition is not a condition until you say ::value
+
+// ::conditional_t picks a type. picking ::void and emitting it prints nothing at all
+::emit<
+    ::conditional_t<
+        ::less<::difference<'B', 'A'>, ::difference<'A', 'A'>>::value,
+        ::decltype(::difference<'Z', 'A'>),
+        ::void
+    >
+>::commit;
+
+// ::conditional does the same for values. this prints 9
+::emit<
+    ::decltype(
+        ::conditional<
+            ::is_same<::remove_cv_t<::int32_t>, ::int32_t>::value,
+            ::difference<'J', 'A'>,
+            ::difference<'A', 'A'>
+        >
+    )
+>::commit;
+
+// two arrays are the same type when their extents agree. this prints 1
+::emit<
+    ::decltype(
+        ::conditional<
+            ::is_same<
+                ::array<::byte, ::difference<'C', 'A'>>,
+                ::array<::int32_t, ::sum<::difference<'B', 'A'>, ::difference<'B', 'A'>>>
+            >::value,
+            ::difference<'B', 'A'>,
+            ::difference<'A', 'A'>
+        >
+    )
+>::commit;