1 files changed, 90 insertions, 0 deletions
diff --git a/misc/examples/box2.c b/misc/examples/box2.c
new file mode 100644
index 00000000..b9628eeb
--- /dev/null
+++ b/misc/examples/box2.c
@@ -0,0 +1,90 @@
+// https://doc.rust-lang.org/rust-by-example/std/box.html
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stc/ccommon.h>
+
+struct {
+    double x;
+    double y;
+} typedef Point;
+
+// A Rectangle can be specified by where its top left and bottom right
+// corners are in space
+struct {
+    Point top_left;
+    Point bottom_right;
+} typedef Rectangle;
+
+#define i_val Point
+#define i_opt c_no_lookup
+#include <stc/cbox.h> // cbox_Point
+
+#define i_val Rectangle
+#define i_opt c_no_lookup
+#include <stc/cbox.h> // cbox_Rectangle
+
+// Box in box:
+#define i_valboxed cbox_Point    // NB: use i_valboxed when value is a cbox or carc!
+                                 // it will auto define i_valdrop, i_valfrom, and i_cmp.
+#define i_tag BoxPoint
+#define i_opt c_no_lookup
+#include <stc/cbox.h> // cbox_BoxPoint
+
+Point origin(void) {
+    return (Point){ .x=1.0, .y=2.0 };
+}
+
+cbox_Point boxed_origin(void) {
+    // Allocate this point on the heap, and return a pointer to it
+    return cbox_Point_make((Point){ .x=2.0, .y=3.0 });
+}
+
+
+int main(void) {
+    // Stack allocated variables
+    Point point = origin();
+    Rectangle rectangle = (Rectangle){
+        .top_left = origin(),
+        .bottom_right = (Point){ .x=3.0, .y=-4.0 }
+    };
+
+    // Declare auto-deleted box objects
+    c_auto (cbox_Rectangle, boxed_rectangle)
+    c_auto (cbox_Point, boxed_point)
+    c_auto (cbox_BoxPoint, box_in_a_box, boxbox2)
+    {
+        // Heap allocated rectangle
+        boxed_rectangle = cbox_Rectangle_make((Rectangle){
+            .top_left = origin(),
+            .bottom_right = (Point){ .x=3.0, .y=-4.0 }
+        });
+
+        // The output of functions can be boxed
+        boxed_point = cbox_Point_from(origin());
+
+        // Double indirection
+        box_in_a_box = cbox_BoxPoint_make(boxed_origin());
+        boxbox2 = cbox_BoxPoint_from(point); // !!
+        printf("boxbox2: x=%f\n", boxbox2.get->get->x);
+
+        printf("Point occupies %" c_ZU " bytes on the stack\n",
+                sizeof(point));
+        printf("Rectangle occupies %" c_ZU " bytes on the stack\n",
+                sizeof(rectangle));
+
+        // box size == pointer size
+        printf("Boxed point occupies %" c_ZU " bytes on the stack\n",
+                sizeof(boxed_point));
+        printf("Boxed rectangle occupies %" c_ZU " bytes on the stack\n",
+                sizeof(boxed_rectangle));
+        printf("Boxed box occupies %" c_ZU " bytes on the stack\n",
+                sizeof(box_in_a_box));
+
+        // Copy the data contained in `boxed_point` into `unboxed_point`
+        Point unboxed_point = *boxed_point.get;
+        printf("Unboxed point occupies %" c_ZU " bytes on the stack\n",
+                sizeof(unboxed_point));
+    }
+}