datatype99: add package (#4545)

* datatype99: add package

* datatype99: test against older version

* datatype99: improve test

* datatype99: use c11 flag

* Update xmake.lua

---------

Co-authored-by: ruki <waruqi@gmail.com>

packages/d/datatype99/xmake.lua

@@ -0,0 +1,41 @@
+package("datatype99")
+    set_kind("library", { headeronly = true })
+    set_homepage("https://github.com/Hirrolot/datatype99")
+    set_description("Algebraic data types for C99")
+    set_license("MIT")
+
+    add_urls("https://github.com/Hirrolot/datatype99/archive/refs/tags/v$(version).tar.gz",
+             "https://github.com/Hirrolot/datatype99.git")
+
+    add_versions("1.6.3", "0ddc138eac8db19fa22c482d9a2ec107ff622fd7ce61bb0b1eefb4d8f522e01e")
+    add_versions("1.6.4", "f8488decc7ab035e3af77ee62e64fc678d5cb57831457f7270efe003e63d6f09")
+
+    add_deps("metalang99")
+
+    on_install(function(package)
+        os.cp("*.h", package:installdir("include"))
+    end)
+
+    on_test(function(package)
+        assert(package:check_csnippets({test = [[
+            #include <assert.h>
+            datatype(
+                BinaryTree,
+                (Leaf, int),
+                (Node, BinaryTree *, int, BinaryTree *)
+            );
+            int sum(const BinaryTree *tree) {
+                match(*tree) {
+                    of(Leaf, x) return *x;
+                    of(Node, lhs, x, rhs) return sum(*lhs) + *x + sum(*rhs);
+                }
+                return -1;
+            }
+            void test() {
+                BinaryTree leaf5 = Leaf(5);
+                BinaryTree leaf7 = Leaf(7);
+                BinaryTree node = Node(&leaf5, 123, &leaf7);
+                assert(sum(&node) == 135);
+            }
+        ]]}, { configs = { languages = "c11" }, includes = "datatype99.h" }))
+    end)