Added _toval() in carc and cbox. Added dynamic polymorphism example, shape.c.

4 files changed, 142 insertions, 0 deletions

diff --git a/examples/shape.c b/examples/shape.c
new file mode 100644
index 00000000..7dc52759
--- /dev/null
+++ b/examples/shape.c
@@ -0,0 +1,134 @@
+// Demo of typesafe polymorphism in C99, using STC.

+

+#include <stdlib.h>

+#include <stdio.h>

+#include <stc/ccommon.h>

+

+#define c_self(s, T, vtable) \

+    T* self = c_container_of(s, T, vtable)

+#define c_is_first(T, memb) \

+    c_static_assert(offsetof(T, memb) == 0)

+

+

+typedef struct { float x, y; } Point;

+

+typedef struct Shape {

+    void (*drop)(struct Shape**);

+    void (*draw)(struct Shape**);

+} Shape;

+

+void Shape_drop(Shape** shape)

+{

+}

+

+void Shape_delete(Shape** shape)

+{ 

+    if (shape) {

+        (*shape)->drop(shape);

+        c_free(shape);

+    }

+}

+

+// Triangle implementation

+// ============================================================

+

+typedef struct {

+    Shape* api;

+    Point p[3];

+} Triangle;

+

+c_is_first(Triangle, api);

+

+

+void Triangle_draw(Shape** shape)

+{

+    const c_self(shape, Triangle, api);

+    printf("Triangle: (%g,%g), (%g,%g), (%g,%g)\n",

+           self->p[0].x, self->p[0].y,

+           self->p[1].x, self->p[1].y,

+           self->p[2].x, self->p[2].y);

+}

+

+static Shape Triangle_api = {

+    .drop = Shape_drop,

+    .draw = Triangle_draw,

+};

+

+Shape** Triangle_new(Point a, Point b, Point c)

+{

+    Triangle* s = c_new(Triangle, {&Triangle_api, .p={a, b, c}});

+    return &s->api;

+}

+

+// Polygon implementation

+// ============================================================

+

+#define i_type PVec 

+#define i_val Point

+#include <stc/cstack.h>

+

+typedef struct {

+    Shape* api;

+    PVec points;

+} Polygon;

+

+c_is_first(Polygon, api);

+

+

+void Polygon_drop(Shape** shape)

+{

+    puts("drop poly");

+    c_self(shape, Polygon, api);

+    PVec_drop(&self->points);

+}

+

+void Polygon_draw(Shape** shape)

+{

+    const c_self(shape, Polygon, api);

+    printf("Polygon:");

+    c_foreach (i, PVec, self->points)

+        printf(" (%g,%g)", i.ref->x, i.ref->y);

+    puts("");

+}

+

+static Shape Polygon_api = {

+    .drop = Polygon_drop,

+    .draw = Polygon_draw,

+};

+

+Shape** Polygon_new(void)

+{

+    Polygon* s = c_new(Polygon, {&Polygon_api, .points=PVec_init()});

+    return &s->api;

+}

+

+void Polygon_addPoint(Shape** shape, Point p)

+{

+    c_self(shape, Polygon, api);

+    PVec_push(&self->points, p);

+}

+

+

+// Test

+// ============================================================

+

+void testShape(Shape** shape)

+{

+    (*shape)->draw(shape);

+}

+

+int main(void)

+{

+    c_autovar (Shape** tria = NULL, Shape_delete(tria))

+    c_autovar (Shape** poly = Polygon_new(), Shape_delete(poly))

+    {

+        tria = Triangle_new((Point){5, 7}, (Point){12, 7}, (Point){12, 20});

+

+        c_apply(p, Polygon_addPoint(poly, p), Point, {

+            {5, 7}, {12, 7}, {12, 20}, {82, 33}, {17, 56},

+        });

+

+        testShape(tria);

+        testShape(poly);

+    }

+}

diff --git a/include/stc/carc.h b/include/stc/carc.h
index 6c591d2c..e4a69e80 100644
--- a/include/stc/carc.h
+++ b/include/stc/carc.h
@@ -115,6 +115,9 @@ STC_INLINE _cx_self _cx_memb(_make)(_cx_value val) {
 STC_INLINE _cx_raw _cx_memb(_toraw)(const _cx_self* self)

     { return i_keyto(self->get); }

 

+STC_INLINE _cx_value _cx_memb(_toval)(const _cx_self* self)

+    { return *self->get; }

+

 STC_INLINE _cx_self _cx_memb(_move)(_cx_self* self) {

     _cx_self ptr = *self;

     self->get = NULL, self->use_count = NULL;

diff --git a/include/stc/cbox.h b/include/stc/cbox.h
index cb5cada3..73b437d4 100644
--- a/include/stc/cbox.h
+++ b/include/stc/cbox.h
@@ -97,6 +97,9 @@ STC_INLINE _cx_self _cx_memb(_make)(_cx_value val) {
 STC_INLINE _cx_raw _cx_memb(_toraw)(const _cx_self* self)

     { return i_keyto(self->get); }

 

+STC_INLINE _cx_value _cx_memb(_toval)(const _cx_self* self)

+    { return *self->get; }

+

 // destructor

 STC_INLINE void _cx_memb(_drop)(_cx_self* self) {

     if (self->get) {

diff --git a/include/stc/template.h b/include/stc/template.h
index f55a3354..6af10ace 100644
--- a/include/stc/template.h
+++ b/include/stc/template.h
@@ -114,6 +114,7 @@
 #elif defined i_key_arcbox

   #define i_key_bind i_key_arcbox

   #define i_keyraw c_paste(i_key_arcbox, _value)

+  #define i_keyto c_paste(i_key, _toval)

   #define i_eq c_paste(i_key_arcbox, _value_eq)

 #endif

 

@@ -196,6 +197,7 @@
 #elif defined i_val_arcbox

   #define i_val_bind i_val_arcbox

   #define i_valraw c_paste(i_val_arcbox, _value)

+  #define i_valto c_paste(i_val, _toval)  

 #endif

 

 #ifdef i_val_bind