1 files changed, 34 insertions, 0 deletions
diff --git a/spec/ruby/optional/capi/ext/language_spec.c b/spec/ruby/optional/capi/ext/language_spec.c
new file mode 100644
index 0000000000..5aeac63f53
--- /dev/null
+++ b/spec/ruby/optional/capi/ext/language_spec.c
@@ -0,0 +1,34 @@
+#include "ruby.h"
+#include "rubyspec.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static VALUE language_spec_switch(VALUE self, VALUE value) {
+  if (value == ID2SYM(rb_intern("undef"))) {
+    value = Qundef;
+  }
+
+  switch (value) {
+    case Qtrue:
+      return ID2SYM(rb_intern("true"));
+    case Qfalse:
+      return ID2SYM(rb_intern("false"));
+    case Qnil:
+      return ID2SYM(rb_intern("nil"));
+    case Qundef:
+      return ID2SYM(rb_intern("undef"));
+    default:
+      return ID2SYM(rb_intern("default"));
+  }
+}
+
+void Init_language_spec(void) {
+  VALUE cls = rb_define_class("CApiLanguageSpecs", rb_cObject);
+  rb_define_method(cls, "switch", language_spec_switch, 1);
+}
+
+#ifdef __cplusplus
+}
+#endif